public class

View

extends Object
implements Drawable.Callback KeyEvent.Callback

java.lang.Object
↳	android.view.View

Known Direct Subclasses

AnalogClock, ImageView, KeyboardView, ProgressBar, SurfaceView, TextView, ViewGroup, ViewStub

Known Indirect Subclasses

AbsListView, AbsSeekBar, AbsSpinner, AbsoluteLayout, AdapterView<T extends Adapter>, AppWidgetHostView, AutoCompleteTextView, Button, CheckBox, CheckedTextView, Chronometer, CompoundButton, DatePicker, DialerFilter, DigitalClock, EditText, ExpandableListView, ExtractEditText, FrameLayout, GLSurfaceView, Gallery, GridView, HorizontalScrollView, ImageButton, ImageSwitcher, LinearLayout, ListView, MediaController, MultiAutoCompleteTextView, RadioButton, RadioGroup, RatingBar, RelativeLayout, ScrollView, SeekBar, SlidingDrawer, Spinner, TabHost, TabWidget, TableLayout, TableRow, TextSwitcher, TimePicker, ToggleButton, TwoLineListItem, VideoView, ViewAnimator, ViewFlipper, ViewSwitcher, WebView, ZoomButton, ZoomControls

AbsListView	Common code shared between ListView and GridView
AbsSeekBar
AbsSpinner	An abstract base class for spinner widgets.
AbsoluteLayout	This class is deprecated. Use FrameLayout, RelativeLayout or a custom layout instead.
AdapterView<T extends Adapter>	An AdapterView is a view whose children are determined by an Adapter.
AppWidgetHostView	Provides the glue to show AppWidget views.
AutoCompleteTextView	An editable text view that shows completion suggestions automatically while the user is typing.
Button	`Button` represents a push-button widget.
CheckBox	A checkbox is a specific type of two-states button that can be either checked or unchecked.
CheckedTextView	An extension to TextView that supports the Checkable interface.
Chronometer	Class that implements a simple timer.
CompoundButton	A button with two states, checked and unchecked.
DatePicker	A view for selecting a month / year / day based on a calendar like layout.
DialerFilter
DigitalClock	Like AnalogClock, but digital.
EditText	EditText is a thin veneer over TextView that configures itself to be editable.
ExpandableListView	A view that shows items in a vertically scrolling two-level list.
ExtractEditText	Specialization of EditText for showing and interacting with the extracted text in a full-screen input method.
FrameLayout	FrameLayout is designed to block out an area on the screen to display a single item.
GLSurfaceView	An implementation of SurfaceView that uses the dedicated surface for displaying OpenGL rendering.
Gallery	A view that shows items in a center-locked, horizontally scrolling list.
GridView	A view that shows items in two-dimensional scrolling grid.
HorizontalScrollView	Layout container for a view hierarchy that can be scrolled by the user, allowing it to be larger than the physical display.
ImageButton	An image button displays an image that can be pressed, or clicked, by the user.
ImageSwitcher
LinearLayout	A Layout that arranges its children in a single column or a single row.
ListView	A view that shows items in a vertically scrolling list.
MediaController	A view containing controls for a MediaPlayer.
MultiAutoCompleteTextView	An editable text view, extending AutoCompleteTextView, that can show completion suggestions for the substring of the text where the user is typing instead of necessarily for the entire thing.
RadioButton	A radio button is a two-states button that can be either checked or unchecked.
RadioGroup	This class is used to create a multiple-exclusion scope for a set of radio buttons.
RatingBar	A RatingBar is an extension of SeekBar and ProgressBar that shows a rating in stars.
RelativeLayout	A Layout where the positions of the children can be described in relation to each other or to the parent.
ScrollView	Layout container for a view hierarchy that can be scrolled by the user, allowing it to be larger than the physical display.
SeekBar	A SeekBar is an extension of ProgressBar that adds a draggable thumb.
SlidingDrawer	SlidingDrawer hides content out of the screen and allows the user to drag a handle to bring the content on screen.
Spinner	A view that displays one child at a time and lets the user pick among them.
TabHost	Container for a tabbed window view.
TabWidget	Displays a list of tab labels representing each page in the parent's tab collection.
TableLayout	A layout that arranges its children into rows and columns.
TableRow	A layout that arranges its children horizontally.
TextSwitcher	Specialized ViewSwitcher that contains only children of type TextView.
TimePicker	A view for selecting the time of day, in either 24 hour or AM/PM mode.
ToggleButton	Displays checked/unchecked states as a button with a "light" indicator and by default accompanied with the text "ON" or "OFF".
TwoLineListItem	A view group with two children, intended for use in ListViews.
VideoView	Displays a video file.
ViewAnimator	Base class for a FrameLayout container that will perform animations when switching between its views.
ViewFlipper	Simple ViewAnimator that will animate between two or more views that have been added to it.
ViewSwitcher	ViewAnimator that switches between two views, and has a factory from which these views are created.
WebView	A View that displays web pages.
ZoomButton
ZoomControls	The `ZoomControls` class displays a simple set of controls used for zooming and provides callbacks to register for events.

Class Overview

This class represents the basic building block for user interface components. A View occupies a rectangular area on the screen and is responsible for drawing and event handling. View is the base class for widgets, which are used to create interactive UI components (buttons, text fields, etc.). The ViewGroup subclass is the base class for layouts, which are invisible containers that hold other Views (or other ViewGroups) and define their layout properties.

For an introduction to using this class to develop your application's user interface, read the Developer Guide documentation on User Interface. Special topics include:
Declaring Layout
Creating Menus
Common Layout Objects
Binding to Data with AdapterView
Handling UI Events
Applying Styles and Themes
Building Custom Components
How Android Draws Views.

Using Views

All of the views in a window are arranged in a single tree. You can add views either from code or by specifying a tree of views in one or more XML layout files. There are many specialized subclasses of views that act as controls or are capable of displaying text, images, or other content.

Once you have created a tree of views, there are typically a few types of common operations you may wish to perform:

Set properties: for example setting the text of a TextView. The available properties and the methods that set them will vary among the different subclasses of views. Note that properties that are known at build time can be set in the XML layout files.
Set focus: The framework will handled moving focus in response to user input. To force focus to a specific view, call requestFocus().
Set up listeners: Views allow clients to set listeners that will be notified when something interesting happens to the view. For example, all views will let you set a listener to be notified when the view gains or loses focus. You can register such a listener using setOnFocusChangeListener(View.OnFocusChangeListener). Other view subclasses offer more specialized listeners. For example, a Button exposes a listener to notify clients when the button is clicked.
Set visibility: You can hide or show views using setVisibility(int).

Note: The Android framework is responsible for measuring, laying out and drawing views. You should not call methods that perform these actions on views yourself unless you are actually implementing a ViewGroup.

Implementing a Custom View

To implement a custom view, you will usually begin by providing overrides for some of the standard methods that the framework calls on all views. You do not need to override all of these methods. In fact, you can start by just overriding onDraw(android.graphics.Canvas).

Category	Methods	Description
Creation	Constructors	There is a form of the constructor that are called when the view is created from code and a form that is called when the view is inflated from a layout file. The second form should parse and apply any attributes defined in the layout file.
Creation	`onFinishInflate()`	Called after a view and all of its children has been inflated from XML.
Layout	`onMeasure(int, int)`	Called to determine the size requirements for this view and all of its children.
	`onLayout(boolean, int, int, int, int)`	Called when this view should assign a size and position to all of its children.
	`onSizeChanged(int, int, int, int)`	Called when the size of this view has changed.
Drawing	`onDraw(Canvas)`	Called when the view should render its content.
Event processing	`onKeyDown(int, KeyEvent)`	Called when a new key event occurs.
	`onKeyUp(int, KeyEvent)`	Called when a key up event occurs.
	`onTrackballEvent(MotionEvent)`	Called when a trackball motion event occurs.
	`onTouchEvent(MotionEvent)`	Called when a touch screen motion event occurs.
Focus	`onFocusChanged(boolean, int, Rect)`	Called when the view gains or loses focus.
Focus	`onWindowFocusChanged(boolean)`	Called when the window containing the view gains or loses focus.
Attaching	`onAttachedToWindow()`	Called when the view is attached to a window.
	`onDetachedFromWindow()`	Called when the view is detached from its window.
	`onWindowVisibilityChanged(int)`	Called when the visibility of the window containing the view has changed.

IDs

Views may have an integer id associated with them. These ids are typically assigned in the layout XML files, and are used to find specific views within the view tree. A common pattern is to:

Define a Button in the layout file and assign it a unique ID.

 <Button id="@+id/my_button"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:text="@string/my_button_text"/>

From the onCreate method of an Activity, find the Button

      Button myButton = (Button) findViewById(R.id.my_button);

View IDs need not be unique throughout the tree, but it is good practice to ensure that they are at least unique within the part of the tree you are searching.

Position

The geometry of a view is that of a rectangle. A view has a location, expressed as a pair of left and top coordinates, and two dimensions, expressed as a width and a height. The unit for location and dimensions is the pixel.

It is possible to retrieve the location of a view by invoking the methods getLeft() and getTop(). The former returns the left, or X, coordinate of the rectangle representing the view. The latter returns the top, or Y, coordinate of the rectangle representing the view. These methods both return the location of the view relative to its parent. For instance, when getLeft() returns 20, that means the view is located 20 pixels to the right of the left edge of its direct parent.

In addition, several convenience methods are offered to avoid unnecessary computations, namely getRight() and getBottom(). These methods return the coordinates of the right and bottom edges of the rectangle representing the view. For instance, calling getRight() is similar to the following computation: getLeft() + getWidth() (see Size for more information about the width.)

Size, padding and margins

The size of a view is expressed with a width and a height. A view actually possess two pairs of width and height values.

The first pair is known as measured width and measured height. These dimensions define how big a view wants to be within its parent (see Layout for more details.) The measured dimensions can be obtained by calling getMeasuredWidth() and getMeasuredHeight().

The second pair is simply known as width and height, or sometimes drawing width and drawing height. These dimensions define the actual size of the view on screen, at drawing time and after layout. These values may, but do not have to, be different from the measured width and height. The width and height can be obtained by calling getWidth() and getHeight().

To measure its dimensions, a view takes into account its padding. The padding is expressed in pixels for the left, top, right and bottom parts of the view. Padding can be used to offset the content of the view by a specific amount of pixels. For instance, a left padding of 2 will push the view's content by 2 pixels to the right of the left edge. Padding can be set using the setPadding(int, int, int, int) method and queried by calling getPaddingLeft(), getPaddingTop(), getPaddingRight() and getPaddingBottom().

Even though a view can define a padding, it does not provide any support for margins. However, view groups provide such a support. Refer to ViewGroup and ViewGroup.MarginLayoutParams for further information.

Layout

Layout is a two pass process: a measure pass and a layout pass. The measuring pass is implemented in measure(int, int) and is a top-down traversal of the view tree. Each view pushes dimension specifications down the tree during the recursion. At the end of the measure pass, every view has stored its measurements. The second pass happens in layout(int, int, int, int) and is also top-down. During this pass each parent is responsible for positioning all of its children using the sizes computed in the measure pass.

When a view's measure() method returns, its getMeasuredWidth() and getMeasuredHeight() values must be set, along with those for all of that view's descendants. A view's measured width and measured height values must respect the constraints imposed by the view's parents. This guarantees that at the end of the measure pass, all parents accept all of their children's measurements. A parent view may call measure() more than once on its children. For example, the parent may measure each child once with unspecified dimensions to find out how big they want to be, then call measure() on them again with actual numbers if the sum of all the children's unconstrained sizes is too big or too small.

The measure pass uses two classes to communicate dimensions. The View.MeasureSpec class is used by views to tell their parents how they want to be measured and positioned. The base LayoutParams class just describes how big the view wants to be for both width and height. For each dimension, it can specify one of:

an exact number
FILL_PARENT, which means the view wants to be as big as its parent (minus padding)
WRAP_CONTENT, which means that the view wants to be just big enough to enclose its content (plus padding).

There are subclasses of LayoutParams for different subclasses of ViewGroup. For example, AbsoluteLayout has its own subclass of LayoutParams which adds an X and Y value.

MeasureSpecs are used to push requirements down the tree from parent to child. A MeasureSpec can be in one of three modes:

UNSPECIFIED: This is used by a parent to determine the desired dimension of a child view. For example, a LinearLayout may call measure() on its child with the height set to UNSPECIFIED and a width of EXACTLY 240 to find out how tall the child view wants to be given a width of 240 pixels.
EXACTLY: This is used by the parent to impose an exact size on the child. The child must use this size, and guarantee that all of its descendants will fit within this size.
AT_MOST: This is used by the parent to impose a maximum size on the child. The child must gurantee that it and all of its descendants will fit within this size.

To intiate a layout, call requestLayout(). This method is typically called by a view on itself when it believes that is can no longer fit within its current bounds.

Drawing

Drawing is handled by walking the tree and rendering each view that intersects the the invalid region. Because the tree is traversed in-order, this means that parents will draw before (i.e., behind) their children, with siblings drawn in the order they appear in the tree. If you set a background drawable for a View, then the View will draw it for you before calling back to its onDraw() method.

Note that the framework will not draw views that are not in the invalid region.

To force a view to draw, call invalidate().

Event Handling and Threading

The basic cycle of a view is as follows:

An event comes in and is dispatched to the appropriate view. The view handles the event and notifies any listeners.
If in the course of processing the event, the view's bounds may need to be changed, the view will call requestLayout().
Similarly, if in the course of processing the event the view's appearance may need to be changed, the view will call invalidate().
If either requestLayout() or invalidate() were called, the framework will take care of measuring, laying out, and drawing the tree as appropriate.

Note: The entire view tree is single threaded. You must always be on the UI thread when calling any method on any view. If you are doing work on other threads and want to update the state of a view from that thread, you should use a Handler.

Focus Handling

The framework will handle routine focus movement in response to user input. This includes changing the focus as views are removed or hidden, or as new views become available. Views indicate their willingness to take focus through the isFocusable() method. To change whether a view can take focus, call setFocusable(boolean). When in touch mode (see notes below) views indicate whether they still would like focus via isFocusableInTouchMode() and can change this via setFocusableInTouchMode(boolean).

Focus movement is based on an algorithm which finds the nearest neighbor in a given direction. In rare cases, the default algorithm may not match the intended behavior of the developer. In these situations, you can provide explicit overrides by using these XML attributes in the layout file:

 nextFocusDown
 nextFocusLeft
 nextFocusRight
 nextFocusUp

To get a particular view to take focus, call requestFocus().

Touch Mode

When a user is navigating a user interface via directional keys such as a D-pad, it is necessary to give focus to actionable items such as buttons so the user can see what will take input. If the device has touch capabilities, however, and the user begins interacting with the interface by touching it, it is no longer necessary to always highlight, or give focus to, a particular view. This motivates a mode for interaction named 'touch mode'.

For a touch capable device, once the user touches the screen, the device will enter touch mode. From this point onward, only views for which isFocusableInTouchMode() is true will be focusable, such as text editing widgets. Other views that are touchable, like buttons, will not take focus when touched; they will only fire the on click listeners.

Any time a user hits a directional key, such as a D-pad direction, the view device will exit touch mode, and find a view to take focus, so that the user may resume interacting with the user interface without touching the screen again.

The touch mode state is maintained across Activitys. Call isInTouchMode() to see whether the device is currently in touch mode.

Scrolling

The framework provides basic support for views that wish to internally scroll their content. This includes keeping track of the X and Y scroll offset as well as mechanisms for drawing scrollbars. See scrollBy(int, int), scrollTo(int, int) for more details.

Animation

You can attach an Animation object to a view using setAnimation(Animation) or startAnimation(Animation). The animation can alter the scale, rotation, translation and alpha of a view over time. If the animation is attached to a view that has children, the animation will affect the entire subtree rooted by that node. When an animation is started, the framework will take care of redrawing the appropriate views until the animation completes.

Summary

Nested Classes
public class	View.BaseSavedState	Base class for derived classes that want to save and restore their own state in onSaveInstanceState().
public class	View.MeasureSpec	A MeasureSpec encapsulates the layout requirements passed from parent to child.
public class	View.OnClickListener	Interface definition for a callback to be invoked when a view is clicked.
public class	View.OnCreateContextMenuListener	Interface definition for a callback to be invoked when the context menu for this view is being built.
public class	View.OnFocusChangeListener	Interface definition for a callback to be invoked when the focus state of a view changed.
public class	View.OnKeyListener	Interface definition for a callback to be invoked when a key event is dispatched to this view.
public class	View.OnLongClickListener	Interface definition for a callback to be invoked when a view has been clicked and held.
public class	View.OnTouchListener	Interface definition for a callback to be invoked when a touch event is dispatched to this view.

XML Attributes
Attribute Name	Related Method	Description
android:background	setBackgroundResource(int)	A drawable to use as the background.
android:clickable	setClickable(boolean)	Defines whether this view reacts to click events.
android:drawingCacheQuality	setDrawingCacheQuality(int)	Defines the quality of translucent drawing caches.
android:fadingEdge	setVerticalFadingEdgeEnabled(boolean)	Defines which edges should be fadeded on scrolling.
android:fadingEdgeLength	getVerticalFadingEdgeLength()	Defines the length of the fading edges.
android:fitsSystemWindows		Boolean internal attribute to adjust view layout based on system windows such as the status bar.
android:focusable	setFocusable(boolean)	Boolean that controls whether a view can take focus.
android:focusableInTouchMode	setFocusableInTouchMode(boolean)	Boolean that controls whether a view can take focus while in touch mode.
android:hapticFeedbackEnabled	setHapticFeedbackEnabled(boolean)	Boolean that controls whether a view should have haptic feedback enabled for events such as long presses.
android:id	setId(int)	Supply an identifier name for this view, to later retrieve it with View.findViewById() or Activity.findViewById().
android:keepScreenOn	setKeepScreenOn(boolean)	Controls whether the view's window should keep the screen on while visible.
android:longClickable	setLongClickable(boolean)	Defines whether this view reacts to long click events.
android:nextFocusDown	setNextFocusDownId(int)	Defines the next view to give focus to when the next focus is FOCUS_DOWN If the reference refers to a view that does not exist or is part of a hierarchy that is invisible, a RuntimeException will result when the reference is accessed.
android:nextFocusLeft	setNextFocusLeftId(int)	Defines the next view to give focus to when the next focus is FOCUS_LEFT.
android:nextFocusRight	setNextFocusRightId(int)	Defines the next view to give focus to when the next focus is FOCUS_RIGHT If the reference refers to a view that does not exist or is part of a hierarchy that is invisible, a RuntimeException will result when the reference is accessed.
android:nextFocusUp	setNextFocusUpId(int)	Defines the next view to give focus to when the next focus is FOCUS_UP If the reference refers to a view that does not exist or is part of a hierarchy that is invisible, a RuntimeException will result when the reference is accessed.
android:padding	setPadding(int,int,int,int)	Sets the padding, in pixels, of all four edges.
android:paddingBottom	setPadding(int,int,int,int)	Sets the padding, in pixels, of the bottom edge; see padding.
android:paddingLeft	setPadding(int,int,int,int)	Sets the padding, in pixels, of the left edge; see padding.
android:paddingRight	setPadding(int,int,int,int)	Sets the padding, in pixels, of the right edge; see padding.
android:paddingTop	setPadding(int,int,int,int)	Sets the padding, in pixels, of the top edge; see padding.
android:saveEnabled	setSaveEnabled(boolean)	If unset, no state will be saved for this view when it is being frozen.
android:scrollX		The initial horizontal scroll offset, in pixels.
android:scrollY		The initial vertical scroll offset, in pixels.
android:scrollbarAlwaysDrawHorizontalTrack		Defines whether the horizontal scrollbar track should always be drawn.
android:scrollbarAlwaysDrawVerticalTrack		Defines whether the vertical scrollbar track should always be drawn Must be a boolean value, either "`true`" or "`false`".
android:scrollbarSize		Sets the width of vertical scrollbars and height of horizontal scrollbars.
android:scrollbarThumbHorizontal		Defines the horizontal scrollbar thumb drawable.
android:scrollbarThumbVertical		Defines the vertical scrollbar thumb drawable.
android:scrollbarTrackHorizontal		Defines the horizontal scrollbar track drawable.
android:scrollbarTrackVertical		Defines the vertical scrollbar track drawable.
android:scrollbars		Defines which scrollbars should be displayed on scrolling or not.
android:soundEffectsEnabled	setSoundEffectsEnabled(boolean)	Boolean that controls whether a view should have sound effects enabled for events such as clicking and touching.
android:visibility	setVisibility(int)	Controls the initial visibility of the view.

Constants
int	DRAWING_CACHE_QUALITY_AUTO	Enables automatic quality mode for the drawing cache.
int	DRAWING_CACHE_QUALITY_HIGH	Enables high quality mode for the drawing cache.
int	DRAWING_CACHE_QUALITY_LOW	Enables low quality mode for the drawing cache.
int[]	EMPTY_STATE_SET	Indicates the view has no states set.
int[]	ENABLED_FOCUSED_SELECTED_STATE_SET	Indicates the view is enabled, focused and selected.
int[]	ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET	Indicates the view is enabled, focused, selected and its window has the focus.
int[]	ENABLED_FOCUSED_STATE_SET	Indicates the view is enabled and has the focus.
int[]	ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET	Indicates the view is enabled, focused and its window has the focus.
int[]	ENABLED_SELECTED_STATE_SET	Indicates the view is enabled and selected.
int[]	ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET	Indicates the view is enabled, selected and its window has the focus.
int[]	ENABLED_STATE_SET	Indicates the view is enabled.
int[]	ENABLED_WINDOW_FOCUSED_STATE_SET	Indicates the view is enabled and that its window has focus.
int[]	FOCUSED_SELECTED_STATE_SET	Indicates the view is focused and selected.
int[]	FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET	Indicates the view is focused, selected and its window has the focus.
int[]	FOCUSED_STATE_SET	Indicates the view is focused.
int[]	FOCUSED_WINDOW_FOCUSED_STATE_SET	Indicates the view has the focus and that its window has the focus.
int	FOCUS_BACKWARD	Use with focusSearch(int).
int	FOCUS_DOWN	Use with focusSearch(int).
int	FOCUS_FORWARD	Use with focusSearch(int).
int	FOCUS_LEFT	Use with focusSearch(int).
int	FOCUS_RIGHT	Use with focusSearch(int).
int	FOCUS_UP	Use with focusSearch(int).
int	GONE	This view is invisible, and it doesn't take any space for layout purposes.
int	HAPTIC_FEEDBACK_ENABLED	View flag indicating whether this view should have haptic feedback enabled for events such as long presses.
int	INVISIBLE	This view is invisible, but it still takes up space for layout purposes.
int	KEEP_SCREEN_ON	View flag indicating that the screen should remain on while the window containing this view is visible to the user.
int	NO_ID	Used to mark a View that has no ID.
int[]	PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET	Indicates the view is pressed, enabled, focused and selected.
int[]	PRESSED_ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET	Indicates the view is pressed, enabled, focused, selected and its window has the focus.
int[]	PRESSED_ENABLED_FOCUSED_STATE_SET	Indicates the view is pressed, enabled and focused.
int[]	PRESSED_ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET	Indicates the view is pressed, enabled, focused and its window has the focus.
int[]	PRESSED_ENABLED_SELECTED_STATE_SET	Indicates the view is pressed, enabled and selected.
int[]	PRESSED_ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET	Indicates the view is pressed, enabled, selected and its window has the focus.
int[]	PRESSED_ENABLED_STATE_SET	Indicates the view is pressed and enabled.
int[]	PRESSED_ENABLED_WINDOW_FOCUSED_STATE_SET	Indicates the view is pressed, enabled and its window has the focus.
int[]	PRESSED_FOCUSED_SELECTED_STATE_SET	Indicates the view is pressed, focused and selected.
int[]	PRESSED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET	Indicates the view is pressed, focused, selected and its window has the focus.
int[]	PRESSED_FOCUSED_STATE_SET	Indicates the view is pressed and focused.
int[]	PRESSED_FOCUSED_WINDOW_FOCUSED_STATE_SET	Indicates the view is pressed, focused and its window has the focus.
int[]	PRESSED_SELECTED_STATE_SET	Indicates the view is pressed and selected.
int[]	PRESSED_SELECTED_WINDOW_FOCUSED_STATE_SET	Indicates the view is pressed, selected and its window has the focus.
int[]	PRESSED_WINDOW_FOCUSED_STATE_SET	Indicates the view is pressed and its window has the focus.
int	SCROLLBARS_INSIDE_INSET	The scrollbar style to display the scrollbars inside the padded area, increasing the padding of the view.
int	SCROLLBARS_INSIDE_OVERLAY	The scrollbar style to display the scrollbars inside the content area, without increasing the padding.
int	SCROLLBARS_OUTSIDE_INSET	The scrollbar style to display the scrollbars at the edge of the view, increasing the padding of the view.
int	SCROLLBARS_OUTSIDE_OVERLAY	The scrollbar style to display the scrollbars at the edge of the view, without increasing the padding.
int[]	SELECTED_STATE_SET	Indicates the view is selected.
int[]	SELECTED_WINDOW_FOCUSED_STATE_SET	Indicates the view is selected and that its window has the focus.
int	SOUND_EFFECTS_ENABLED	View flag indicating whether this view should have sound effects enabled for events such as clicking and touching.
String	VIEW_LOG_TAG	The logging tag used by this class with android.util.Log.
int	VISIBLE	This view is visible.
int[]	WINDOW_FOCUSED_STATE_SET	Indicates the view's window has focus.

Public Constructors
	View(Context context) Simple constructor to use when creating a view from code.
	View(Context context, AttributeSet attrs) Constructor that is called when inflating a view from XML.
	View(Context context, AttributeSet attrs, int defStyle) Perform inflation from XML and apply a class-specific base style.

Public Methods
void	addFocusables(ArrayList<View> views, int direction) Add any focusable views that are descendants of this view (possibly including this view if it is focusable itself) to views.
void	addTouchables(ArrayList<View> views) Add any touchable views that are descendants of this view (possibly including this view if it is touchable itself) to views.
void	bringToFront() Change the view's z order in the tree, so it's on top of other sibling views
void	buildDrawingCache() Forces the drawing cache to be built if the drawing cache is invalid.
void	cancelLongPress() Cancels a pending long press.
boolean	checkInputConnectionProxy(View view) Called by the InputMethodManager when a view who is not the current input connection target is trying to make a call on the manager.
void	clearAnimation() Cancels any animations for this view.
void	clearFocus() Called when this view wants to give up focus.
void	computeScroll() Called by a parent to request that a child update its values for mScrollX and mScrollY if necessary.
void	createContextMenu(ContextMenu menu) Show the context menu for this view.
void	destroyDrawingCache() Frees the resources used by the drawing cache.
boolean	dispatchKeyEvent(KeyEvent event) Dispatch a key event to the next view on the focus path.
boolean	dispatchKeyEventPreIme(KeyEvent event) Dispatch a key event before it is processed by any input method associated with the view hierarchy.
boolean	dispatchKeyShortcutEvent(KeyEvent event) Dispatches a key shortcut event.
boolean	dispatchTouchEvent(MotionEvent event) Pass the touch screen motion event down to the target view, or this view if it is the target.
boolean	dispatchTrackballEvent(MotionEvent event) Pass a trackball motion event down to the focused view.
boolean	dispatchUnhandledMove(View focused, int direction) This method is the last chance for the focused view and its ancestors to respond to an arrow key.
void	dispatchWindowFocusChanged(boolean hasFocus) Called when the window containing this view gains or loses window focus.
void	dispatchWindowVisibilityChanged(int visibility) Dispatch a window visibility change down the view hierarchy.
void	draw(Canvas canvas) Manually render this view (and all of its children) to the given Canvas.
View	findFocus() Find the view in the hierarchy rooted at this view that currently has focus.
final View	findViewById(int id) Look for a child view with the given id.
final View	findViewWithTag(Object tag) Look for a child view with the given tag.
View	focusSearch(int direction) Find the nearest view in the specified direction that can take focus.
void	forceLayout() Forces this view to be laid out during the next layout pass.
Animation	getAnimation() Get the animation currently associated with this view.
IBinder	getApplicationWindowToken() Retrieve a unique token identifying the top-level "real" window of the window that this view is attached to.
Drawable	getBackground() Gets the background drawable
int	getBaseline() Return the offset of the widget's text baseline from the widget's top boundary.
final int	getBottom() Bottom position of this view relative to its parent.
final Context	getContext() Returns the context the view is running in, through which it can access the current theme, resources, etc.
static int	getDefaultSize(int size, int measureSpec) Utility to return a default size.
final int[]	getDrawableState() Return an array of resource IDs of the drawable states representing the current state of the view.
Bitmap	getDrawingCache() Returns the bitmap in which this view drawing is cached.
int	getDrawingCacheBackgroundColor()
int	getDrawingCacheQuality() Returns the quality of the drawing cache.
void	getDrawingRect(Rect outRect) Return the visible drawing bounds of your view.
long	getDrawingTime() Return the time at which the drawing of the view hierarchy started.
ArrayList<View>	getFocusables(int direction) Find and return all focusable views that are descendants of this view, possibly including this view if it is focusable itself.
void	getFocusedRect(Rect r) When a view has focus and the user navigates away from it, the next view is searched for starting from the rectangle filled in by this method.
boolean	getGlobalVisibleRect(Rect r, Point globalOffset) If some part of this view is not clipped by any of its parents, then return that area in r in global (root) coordinates.
final boolean	getGlobalVisibleRect(Rect r)
Handler	getHandler()
final int	getHeight() Return the height of your view.
void	getHitRect(Rect outRect) Hit rectangle in parent's coordinates
int	getHorizontalFadingEdgeLength() Returns the size of the horizontal faded edges used to indicate that more content in this view is visible.
int	getId() Returns this view's identifier.
boolean	getKeepScreenOn() Returns whether the screen should remain on, corresponding to the current value of KEEP_SCREEN_ON.
ViewGroup.LayoutParams	getLayoutParams() Get the LayoutParams associated with this view.
final int	getLeft() Left position of this view relative to its parent.
final boolean	getLocalVisibleRect(Rect r)
void	getLocationInWindow(int[] location) Computes the coordinates of this view in its window.
void	getLocationOnScreen(int[] location) Computes the coordinates of this view on the screen.
final int	getMeasuredHeight() The height of this view as measured in the most recent call to measure().
final int	getMeasuredWidth() The width of this view as measured in the most recent call to measure().
int	getNextFocusDownId()
int	getNextFocusLeftId()
int	getNextFocusRightId()
int	getNextFocusUpId()
View.OnFocusChangeListener	getOnFocusChangeListener() Returns the focus-change callback registered for this view.
int	getPaddingBottom() Returns the bottom padding of this view.
int	getPaddingLeft() Returns the left padding of this view.
int	getPaddingRight() Returns the right padding of this view.
int	getPaddingTop() Returns the top padding of this view.
final ViewParent	getParent() Gets the parent of this view.
Resources	getResources() Returns the resources associated with this view.
final int	getRight() Right position of this view relative to its parent.
View	getRootView() Finds the topmost view in the current view hierarchy.
int	getScrollBarStyle() Returns the current scrollbar style.
final int	getScrollX() Return the scrolled left position of this view.
final int	getScrollY() Return the scrolled top position of this view.
int	getSolidColor() Override this if your view is known to always be drawn on top of a solid color background, and needs to draw fading edges.
Object	getTag() Returns this view's tag.
final int	getTop() Top position of this view relative to its parent.
TouchDelegate	getTouchDelegate() Gets the TouchDelegate for this View.
ArrayList<View>	getTouchables() Find and return all touchable views that are descendants of this view, possibly including this view if it is touchable itself.
int	getVerticalFadingEdgeLength() Returns the size of the vertical faded edges used to indicate that more content in this view is visible.
int	getVerticalScrollbarWidth() Returns the width of the vertical scrollbar.
ViewTreeObserver	getViewTreeObserver() Returns the ViewTreeObserver for this view's hierarchy.
int	getVisibility() Returns the visibility status for this view.
final int	getWidth() Return the width of the your view.
IBinder	getWindowToken() Retrieve a unique token identifying the window this view is attached to.
int	getWindowVisibility() Returns the current visibility of the window this view is attached to (either GONE, INVISIBLE, or VISIBLE).
void	getWindowVisibleDisplayFrame(Rect outRect) Retrieve the overall visible display size in which the window this view is attached to has been positioned in.
boolean	hasFocus() Returns true if this view has focus iteself, or is the ancestor of the view that has focus.
boolean	hasFocusable() Returns true if this view is focusable or if it contains a reachable View for which hasFocusable() returns true.
boolean	hasWindowFocus() Returns true if this view is in a window that currently has window focus.
static View	inflate(Context context, int resource, ViewGroup root) Inflate a view from an XML resource.
void	invalidate(int l, int t, int r, int b) Mark the the area defined by the rect (l,t,r,b) as needing to be drawn.
void	invalidate() Invalidate the whole view.
void	invalidate(Rect dirty) Mark the the area defined by dirty as needing to be drawn.
void	invalidateDrawable(Drawable drawable) Invalidates the specified Drawable.
boolean	isClickable() Indicates whether this view reacts to click events or not.
boolean	isDrawingCacheEnabled() Indicates whether the drawing cache is enabled for this view.
boolean	isDuplicateParentStateEnabled() Indicates whether this duplicates its drawable state from its parent.
boolean	isEnabled() Returns the enabled status for this view.
final boolean	isFocusable() Returns whether this View is able to take focus.
final boolean	isFocusableInTouchMode() When a view is focusable, it may not want to take focus when in touch mode.
boolean	isFocused() Returns true if this view has focus
boolean	isHapticFeedbackEnabled()
boolean	isHorizontalFadingEdgeEnabled() Indicate whether the horizontal edges are faded when the view is scrolled horizontally.
boolean	isHorizontalScrollBarEnabled() Indicate whether the horizontal scrollbar should be drawn or not.
boolean	isInEditMode() Indicates whether this View is currently in edit mode.
boolean	isInTouchMode() Returns whether the device is currently in touch mode.
boolean	isLayoutRequested() Indicates whether or not this view's layout will be requested during the next hierarchy layout pass.
boolean	isLongClickable() Indicates whether this view reacts to long click events or not.
boolean	isPressed() Indicates whether the view is currently in pressed state.
boolean	isSaveEnabled() Indicates whether this view will save its state (that is, whether its onSaveInstanceState() method will be called).
boolean	isSelected() Indicates the selection state of this view.
boolean	isShown() Returns the visibility of this view and all of its ancestors
boolean	isSoundEffectsEnabled()
boolean	isVerticalFadingEdgeEnabled() Indicate whether the vertical edges are faded when the view is scrolled horizontally.
boolean	isVerticalScrollBarEnabled() Indicate whether the vertical scrollbar should be drawn or not.
final void	layout(int l, int t, int r, int b) Assign a size and position to a view and all of its descendants This is the second phase of the layout mechanism.
final void	measure(int widthMeasureSpec, int heightMeasureSpec) This is called to find out how big a view should be.
void	offsetLeftAndRight(int offset) Offset this view's horizontal location by the specified amount of pixels.
void	offsetTopAndBottom(int offset) Offset this view's vertical location by the specified number of pixels.
boolean	onCheckIsTextEditor() Check whether the called view is a text editor, in which case it would make sense to automatically display a soft input window for it.
InputConnection	onCreateInputConnection(EditorInfo outAttrs) Create a new InputConnection for an InputMethod to interact with the view.
void	onFinishTemporaryDetach() Called after onStartTemporaryDetach() when the container is done changing the view.
boolean	onKeyDown(int keyCode, KeyEvent event) Default implementation of KeyEvent.Callback.onKeyMultiple(): perform press of the view when KEYCODE_DPAD_CENTER or KEYCODE_ENTER is released, if the view is enabled and clickable.
boolean	onKeyMultiple(int keyCode, int repeatCount, KeyEvent event) Default implementation of KeyEvent.Callback.onKeyMultiple(): always returns false (doesn't handle the event).
boolean	onKeyPreIme(int keyCode, KeyEvent event) Handle a key event before it is processed by any input method associated with the view hierarchy.
boolean	onKeyShortcut(int keyCode, KeyEvent event) Called when an unhandled key shortcut event occurs.
boolean	onKeyUp(int keyCode, KeyEvent event) Default implementation of KeyEvent.Callback.onKeyMultiple(): perform clicking of the view when KEYCODE_DPAD_CENTER or KEYCODE_ENTER is released.
void	onStartTemporaryDetach() This is called when a container is going to temporarily detach a child that currently has focus, with ViewGroup.detachViewFromParent.
boolean	onTouchEvent(MotionEvent event) Implement this method to handle touch screen motion events.
boolean	onTrackballEvent(MotionEvent event) Implement this method to handle trackball motion events.
void	onWindowFocusChanged(boolean hasWindowFocus) Called when the window containing this view gains or loses focus.
boolean	performClick() Call this view's OnClickListener, if it is defined.
boolean	performHapticFeedback(int feedbackConstant) BZZZTT!!1! Provide haptic feedback to the user for this view.
boolean	performHapticFeedback(int feedbackConstant, int flags) BZZZTT!!1! Like performHapticFeedback(int), with additional options.
boolean	performLongClick() Call this view's OnLongClickListener, if it is defined.
void	playSoundEffect(int soundConstant) Play a sound effect for this view.
boolean	post(Runnable action) Causes the Runnable to be added to the message queue.
boolean	postDelayed(Runnable action, long delayMillis) Causes the Runnable to be added to the message queue, to be run after the specified amount of time elapses.
void	postInvalidate() Cause an invalidate to happen on a subsequent cycle through the event loop.
void	postInvalidate(int left, int top, int right, int bottom) Cause an invalidate of the specified area to happen on a subsequent cycle through the event loop.
void	postInvalidateDelayed(long delayMilliseconds) Cause an invalidate to happen on a subsequent cycle through the event loop.
void	postInvalidateDelayed(long delayMilliseconds, int left, int top, int right, int bottom) Cause an invalidate of the specified area to happen on a subsequent cycle through the event loop.
void	refreshDrawableState() Call this to force a view to update its drawable state.
boolean	removeCallbacks(Runnable action) Removes the specified Runnable from the message queue.
final boolean	requestFocus() Call this to try to give focus to a specific view or to one of its descendants.
boolean	requestFocus(int direction, Rect previouslyFocusedRect) Call this to try to give focus to a specific view or to one of its descendants and give it hints about the direction and a specific rectangle that the focus is coming from.
final boolean	requestFocus(int direction) Call this to try to give focus to a specific view or to one of its descendants and give it a hint about what direction focus is heading.
final boolean	requestFocusFromTouch() Call this to try to give focus to a specific view or to one of its descendants.
void	requestLayout() Call this when something has changed which has invalidated the layout of this view.
boolean	requestRectangleOnScreen(Rect rectangle, boolean immediate) Request that a rectangle of this view be visible on the screen, scrolling if necessary just enough.
boolean	requestRectangleOnScreen(Rect rectangle) Request that a rectangle of this view be visible on the screen, scrolling if necessary just enough.
static int	resolveSize(int size, int measureSpec) Utility to reconcile a desired size with constraints imposed by a MeasureSpec.
void	restoreHierarchyState(SparseArray<Parcelable> container) Restore this view hierarchy's frozen state from the given container.
void	saveHierarchyState(SparseArray<Parcelable> container) Store this view hierarchy's frozen state into the given container.
void	scheduleDrawable(Drawable who, Runnable what, long when) Schedules an action on a drawable to occur at a specified time.
void	scrollBy(int x, int y) Move the scrolled position of your view.
void	scrollTo(int x, int y) Set the scrolled position of your view.
void	setAnimation(Animation animation) Sets the next animation to play for this view.
void	setBackgroundColor(int color) Sets the background color for this view.
void	setBackgroundDrawable(Drawable d) Set the background to a given Drawable, or remove the background.
void	setBackgroundResource(int resid) Set the background to a given resource.
void	setClickable(boolean clickable) Enables or disables click events for this view.
void	setDrawingCacheBackgroundColor(int color) Setting a solid background color for the drawing cache's bitmaps will improve perfromance and memory usage.
void	setDrawingCacheEnabled(boolean enabled) Enables or disables the drawing cache.
void	setDrawingCacheQuality(int quality) Set the drawing cache quality of this view.
void	setDuplicateParentStateEnabled(boolean enabled) Enables or disables the duplication of the parent's state into this view.
void	setEnabled(boolean enabled) Set the enabled state of this view.
void	setFadingEdgeLength(int length) Set the size of the faded edge used to indicate that more content in this view is available.
void	setFocusable(boolean focusable) Set whether this view can receive the focus.
void	setFocusableInTouchMode(boolean focusableInTouchMode) Set whether this view can receive focus while in touch mode.
void	setHapticFeedbackEnabled(boolean hapticFeedbackEnabled) Set whether this view should have haptic feedback for events such as long presses.
void	setHorizontalFadingEdgeEnabled(boolean horizontalFadingEdgeEnabled) Define whether the horizontal edges should be faded when this view is scrolled horizontally.
void	setHorizontalScrollBarEnabled(boolean horizontalScrollBarEnabled) Define whether the horizontal scrollbar should be drawn or not.
void	setId(int id) Sets the identifier for this view.
void	setKeepScreenOn(boolean keepScreenOn) Controls whether the screen should remain on, modifying the value of KEEP_SCREEN_ON.
void	setLayoutParams(ViewGroup.LayoutParams params) Set the layout parameters associated with this view.
void	setLongClickable(boolean longClickable) Enables or disables long click events for this view.
void	setMinimumHeight(int minHeight) Sets the minimum height of the view.
void	setMinimumWidth(int minWidth) Sets the minimum width of the view.
void	setNextFocusDownId(int nextFocusDownId) Set the id of the view to use for the next focus
void	setNextFocusLeftId(int nextFocusLeftId) Set the id of the view to use for the next focus
void	setNextFocusRightId(int nextFocusRightId) Set the id of the view to use for the next focus
void	setNextFocusUpId(int nextFocusUpId) Set the id of the view to use for the next focus
void	setOnClickListener(View.OnClickListener l) Register a callback to be invoked when this view is clicked.
void	setOnCreateContextMenuListener(View.OnCreateContextMenuListener l) Register a callback to be invoked when the context menu for this view is being built.
void	setOnFocusChangeListener(View.OnFocusChangeListener l) Register a callback to be invoked when focus of this view changed.
void	setOnKeyListener(View.OnKeyListener l) Register a callback to be invoked when a key is pressed in this view.
void	setOnLongClickListener(View.OnLongClickListener l) Register a callback to be invoked when this view is clicked and held.
void	setOnTouchListener(View.OnTouchListener l) Register a callback to be invoked when a touch event is sent to this view.
void	setPadding(int left, int top, int right, int bottom) Sets the padding.
void	setPressed(boolean pressed) Sets the pressed that for this view.
void	setSaveEnabled(boolean enabled) Controls whether the saving of this view's state is enabled (that is, whether its onSaveInstanceState() method will be called).
void	setScrollBarStyle(int style) Specify the style of the scrollbars.
void	setScrollContainer(boolean isScrollContainer) Change whether this view is one of the set of scrollable containers in its window.
void	setSelected(boolean selected) Changes the selection state of this view.
void	setSoundEffectsEnabled(boolean soundEffectsEnabled) Set whether this view should have sound effects enabled for events such as clicking and touching.
void	setTag(Object tag) Sets the tag associated with this view.
void	setTouchDelegate(TouchDelegate delegate) Sets the TouchDelegate for this View.
void	setVerticalFadingEdgeEnabled(boolean verticalFadingEdgeEnabled) Define whether the vertical edges should be faded when this view is scrolled vertically.
void	setVerticalScrollBarEnabled(boolean verticalScrollBarEnabled) Define whether the vertical scrollbar should be drawn or not.
void	setVisibility(int visibility) Set the enabled state of this view.
void	setWillNotCacheDrawing(boolean willNotCacheDrawing) When a View's drawing cache is enabled, drawing is redirected to an offscreen bitmap.
void	setWillNotDraw(boolean willNotDraw) If this view doesn't do any drawing on its own, set this flag to allow further optimizations.
boolean	showContextMenu() Bring up the context menu for this view.
void	startAnimation(Animation animation) Start the specified animation now.
void	unscheduleDrawable(Drawable who, Runnable what) Cancels a scheduled action on a drawable.
void	unscheduleDrawable(Drawable who) Unschedule any events associated with the given Drawable.
boolean	willNotCacheDrawing() Returns whether or not this View can cache its drawing or not.
boolean	willNotDraw() Returns whether or not this View draws on its own.

Protected Methods
int	computeHorizontalScrollExtent() Compute the horizontal extent of the horizontal scrollbar's thumb within the horizontal range.
int	computeHorizontalScrollOffset() Compute the horizontal offset of the horizontal scrollbar's thumb within the horizontal range.
int	computeHorizontalScrollRange() Compute the horizontal range that the horizontal scrollbar represents.
int	computeVerticalScrollExtent() Compute the vertical extent of the horizontal scrollbar's thumb within the vertical range.
int	computeVerticalScrollOffset() Compute the vertical offset of the vertical scrollbar's thumb within the horizontal range.
int	computeVerticalScrollRange() Compute the vertical range that the vertical scrollbar represents.
void	dispatchDraw(Canvas canvas) Called by draw to draw the child views.
void	dispatchRestoreInstanceState(SparseArray<Parcelable> container) Called by restoreHierarchyState(SparseArray) to retrieve the state for this view and its children.
void	dispatchSaveInstanceState(SparseArray<Parcelable> container) Called by saveHierarchyState(SparseArray) to store the state for this view and its children.
void	dispatchSetPressed(boolean pressed) Dispatch setPressed to all of this View's children.
void	dispatchSetSelected(boolean selected) Dispatch setSelected to all of this View's children.
void	drawableStateChanged() This function is called whenever the state of the view changes in such a way that it impacts the state of drawables being shown.
void	finalize() Is called before the object's memory is being reclaimed by the VM.
boolean	fitSystemWindows(Rect insets) Apply the insets for system windows to this view, if the FITS_SYSTEM_WINDOWS flag is set
float	getBottomFadingEdgeStrength() Returns the strength, or intensity, of the bottom faded edge.
int	getBottomPaddingOffset() Amount by which to extend the bottom fading region.
ContextMenu.ContextMenuInfo	getContextMenuInfo() Views should implement this if they have extra information to associate with the context menu.
int	getHorizontalScrollbarHeight() Returns the height of the horizontal scrollbar.
float	getLeftFadingEdgeStrength() Returns the strength, or intensity, of the left faded edge.
int	getLeftPaddingOffset() Amount by which to extend the left fading region.
float	getRightFadingEdgeStrength() Returns the strength, or intensity, of the right faded edge.
int	getRightPaddingOffset() Amount by which to extend the right fading region.
int	getSuggestedMinimumHeight() Returns the suggested minimum height that the view should use.
int	getSuggestedMinimumWidth() Returns the suggested minimum width that the view should use.
float	getTopFadingEdgeStrength() Returns the strength, or intensity, of the top faded edge.
int	getTopPaddingOffset() Amount by which to extend the top fading region.
int	getWindowAttachCount()
void	initializeFadingEdge(TypedArray a) Initializes the fading edges from a given set of styled attributes.
void	initializeScrollbars(TypedArray a) Initializes the scrollbars from a given set of styled attributes.
boolean	isPaddingOffsetRequired() If the View draws content inside its padding and enables fading edges, it needs to support padding offsets.
static int[]	mergeDrawableStates(int[] baseState, int[] additionalState) Merge your own state values in `additionalState` into the base state values `baseState` that were returned by onCreateDrawableState(int).
void	onAnimationEnd() Invoked by a parent ViewGroup to notify the end of the animation currently associated with this view.
void	onAnimationStart() Invoked by a parent ViewGroup to notify the start of the animation currently associated with this view.
void	onAttachedToWindow() This is called when the view is attached to a window.
void	onCreateContextMenu(ContextMenu menu) Views should implement this if the view itself is going to add items to the context menu.
int[]	onCreateDrawableState(int extraSpace) Generate the new Drawable state for this view.
void	onDetachedFromWindow() This is called when the view is detached from a window.
void	onDraw(Canvas canvas) Implement this to do your drawing.
void	onFinishInflate() Finalize inflating a view from XML.
void	onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) Called by the view system when the focus state of this view changes.
void	onLayout(boolean changed, int left, int top, int right, int bottom) Called from layout when this view should assign a size and position to each of its children.
void	onMeasure(int widthMeasureSpec, int heightMeasureSpec) Measure the view and its content to determine the measured width and the measured height.
void	onRestoreInstanceState(Parcelable state) Hook allowing a view to re-apply a representation of its internal state that had previously been generated by onSaveInstanceState().
Parcelable	onSaveInstanceState() Hook allowing a view to generate a representation of its internal state that can later be used to create a new instance with that same state.
void	onScrollChanged(int l, int t, int oldl, int oldt) This is called in response to an internal scroll in this view (i.e., the view scrolled its own contents).
boolean	onSetAlpha(int alpha) Invoked if there is a Transform that involves alpha.
void	onSizeChanged(int w, int h, int oldw, int oldh) This is called during layout when the size of this view has changed.
void	onWindowVisibilityChanged(int visibility) Called when the window containing has change its visibility (between GONE, INVISIBLE, and VISIBLE).
final void	setMeasuredDimension(int measuredWidth, int measuredHeight) This mehod must be called by onMeasure(int, int) to store the measured width and measured height.
boolean	verifyDrawable(Drawable who) If your view subclass is displaying its own Drawable objects, it should override this function and return true for any Drawable it is displaying.

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Inherited Methods

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Is called before the object's memory is being reclaimed by the VM.
final Class<? extends Object>	getClass() Returns the unique instance of Class which represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.

From interface android.graphics.drawable.Drawable.Callback

From interface android.view.KeyEvent.Callback

XML Attributes

android:background

A drawable to use as the background. This can be either a reference to a full drawable resource (such as a PNG image, 9-patch, XML state list description, etc), or a solid color such as "#ff000000" (black).

May be a reference to another resource, in the form "@[+][package:]type:name" or to a theme attribute in the form "?[package:][type:]name".

May be a color value, in the form of "#rgb", "#argb", "#rrggbb", or "#aarrggbb".

This corresponds to the global attribute resource symbol background.

Related Methods

setBackgroundResource(int)

android:clickable

Defines whether this view reacts to click events.

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol clickable.

Related Methods

setClickable(boolean)

android:drawingCacheQuality

Defines the quality of translucent drawing caches. This property is used only when the drawing cache is enabled and translucent. The default value is auto.

Must be one of the following constant values.

Constant	Value	Description
`auto`	0	Lets the framework decide what quality level should be used for the drawing cache.
`low`	1	Low quality. When set to low quality, the drawing cache uses a lower color depth, thus losing precision in rendering gradients, but uses less memory.
`high`	2	High quality. When set to high quality, the drawing cache uses a higher color depth but uses more memory.

This corresponds to the global attribute resource symbol drawingCacheQuality.

Related Methods

setDrawingCacheQuality(int)

android:fadingEdge

Defines which edges should be fadeded on scrolling.

Must be one or more (separated by '|') of the following constant values.

Constant	Value	Description
`none`	0x00000000	No edge is faded.
`horizontal`	0x00001000	Fades horizontal edges only.
`vertical`	0x00002000	Fades vertical edges only.

This corresponds to the global attribute resource symbol fadingEdge.

Related Methods

setVerticalFadingEdgeEnabled(boolean)

android:fadingEdgeLength

Defines the length of the fading edges.

Must be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), mm (millimeters).

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol fadingEdgeLength.

Related Methods

getVerticalFadingEdgeLength()

android:fitsSystemWindows

Boolean internal attribute to adjust view layout based on system windows such as the status bar. If true, adjusts the padding of this view to leave space for the system windows. Will only take effect if this view is in a non-embedded activity.

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol fitsSystemWindows.

Related Methods

android:focusable

Boolean that controls whether a view can take focus. By default the user can not move focus to a view; by setting this attribute to true the view is allowed to take focus. This value does not impact the behavior of directly calling requestFocus(), which will always request focus regardless of this view. It only impacts where focus navigation will try to move focus.

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol focusable.

Related Methods

setFocusable(boolean)

android:focusableInTouchMode

Boolean that controls whether a view can take focus while in touch mode. If this is true for a view, that view can gain focus when clicked on, and can keep focus if another view is clicked on that doesn't have this attribute set to true.

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol focusableInTouchMode.

Related Methods

setFocusableInTouchMode(boolean)

android:hapticFeedbackEnabled

Boolean that controls whether a view should have haptic feedback enabled for events such as long presses.

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol hapticFeedbackEnabled.

Related Methods

setHapticFeedbackEnabled(boolean)

android:id

Supply an identifier name for this view, to later retrieve it with View.findViewById() or Activity.findViewById(). This must be a resource reference; typically you set this using the @+ syntax to create a new ID resources. For example: android:id="@+id/my_id" which allows you to later retrieve the view with findViewById(R.id.my_id).

Must be a reference to another resource, in the form "@[+][package:]type:name" or to a theme attribute in the form "?[package:][type:]name".

This corresponds to the global attribute resource symbol id.

Related Methods

setId(int)

android:keepScreenOn

Controls whether the view's window should keep the screen on while visible.

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol keepScreenOn.

Related Methods

setKeepScreenOn(boolean)

android:longClickable

Defines whether this view reacts to long click events.

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol longClickable.

Related Methods

setLongClickable(boolean)

android:nextFocusDown

Defines the next view to give focus to when the next focus is FOCUS_DOWN If the reference refers to a view that does not exist or is part of a hierarchy that is invisible, a RuntimeException will result when the reference is accessed.

Must be a reference to another resource, in the form "@[+][package:]type:name" or to a theme attribute in the form "?[package:][type:]name".

This corresponds to the global attribute resource symbol nextFocusDown.

Related Methods

setNextFocusDownId(int)

android:nextFocusLeft

Defines the next view to give focus to when the next focus is FOCUS_LEFT. If the reference refers to a view that does not exist or is part of a hierarchy that is invisible, a RuntimeException will result when the reference is accessed.

Must be a reference to another resource, in the form "@[+][package:]type:name" or to a theme attribute in the form "?[package:][type:]name".

This corresponds to the global attribute resource symbol nextFocusLeft.

Related Methods

setNextFocusLeftId(int)

android:nextFocusRight

Defines the next view to give focus to when the next focus is FOCUS_RIGHT If the reference refers to a view that does not exist or is part of a hierarchy that is invisible, a RuntimeException will result when the reference is accessed.

Must be a reference to another resource, in the form "@[+][package:]type:name" or to a theme attribute in the form "?[package:][type:]name".

This corresponds to the global attribute resource symbol nextFocusRight.

Related Methods

setNextFocusRightId(int)

android:nextFocusUp

Defines the next view to give focus to when the next focus is FOCUS_UP If the reference refers to a view that does not exist or is part of a hierarchy that is invisible, a RuntimeException will result when the reference is accessed.

Must be a reference to another resource, in the form "@[+][package:]type:name" or to a theme attribute in the form "?[package:][type:]name".

This corresponds to the global attribute resource symbol nextFocusUp.

Related Methods

setNextFocusUpId(int)

android:padding

Sets the padding, in pixels, of all four edges. Padding is defined as space between the edges of the view and the view's content. A views size will include it's padding. If a background is provided, the padding will initially be set to that (0 if the drawable does not have padding). Explicitly setting a padding value will override the corresponding padding found in the background.

Must be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), mm (millimeters).

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol padding.

Related Methods

setPadding(int,int,int,int)

android:paddingBottom

Sets the padding, in pixels, of the bottom edge; see padding.

Must be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), mm (millimeters).

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol paddingBottom.

Related Methods

setPadding(int,int,int,int)

android:paddingLeft

Sets the padding, in pixels, of the left edge; see padding.

Must be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), mm (millimeters).

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol paddingLeft.

Related Methods

setPadding(int,int,int,int)

android:paddingRight

Sets the padding, in pixels, of the right edge; see padding.

Must be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), mm (millimeters).

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol paddingRight.

Related Methods

setPadding(int,int,int,int)

android:paddingTop

Sets the padding, in pixels, of the top edge; see padding.

Must be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), mm (millimeters).

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol paddingTop.

Related Methods

setPadding(int,int,int,int)

android:saveEnabled

If unset, no state will be saved for this view when it is being frozen. The default is true, allowing the view to be saved (however it also must have an ID assigned to it for its state to be saved). Setting this to false only disables the state for this view, not for its children which may still be saved.

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol saveEnabled.

Related Methods

setSaveEnabled(boolean)

android:scrollX

The initial horizontal scroll offset, in pixels.

Must be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), mm (millimeters).

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol scrollX.

Related Methods

android:scrollY

The initial vertical scroll offset, in pixels.

Must be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), mm (millimeters).

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol scrollY.

Related Methods

android:scrollbarAlwaysDrawHorizontalTrack

Defines whether the horizontal scrollbar track should always be drawn.

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol scrollbarAlwaysDrawHorizontalTrack.

Related Methods

android:scrollbarAlwaysDrawVerticalTrack

Defines whether the vertical scrollbar track should always be drawn

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol scrollbarAlwaysDrawVerticalTrack.

Related Methods

android:scrollbarSize

Sets the width of vertical scrollbars and height of horizontal scrollbars.

Must be a dimension value, which is a floating point number appended with a unit such as "14.5sp". Available units are: px (pixels), dp (density-independent pixels), sp (scaled pixels based on preferred font size), in (inches), mm (millimeters).

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol scrollbarSize.

Related Methods

android:scrollbarThumbHorizontal

Defines the horizontal scrollbar thumb drawable.

Must be a reference to another resource, in the form "@[+][package:]type:name" or to a theme attribute in the form "?[package:][type:]name".

This corresponds to the global attribute resource symbol scrollbarThumbHorizontal.

Related Methods

android:scrollbarThumbVertical

Defines the vertical scrollbar thumb drawable.

Must be a reference to another resource, in the form "@[+][package:]type:name" or to a theme attribute in the form "?[package:][type:]name".

This corresponds to the global attribute resource symbol scrollbarThumbVertical.

Related Methods

android:scrollbarTrackHorizontal

Defines the horizontal scrollbar track drawable.

Must be a reference to another resource, in the form "@[+][package:]type:name" or to a theme attribute in the form "?[package:][type:]name".

This corresponds to the global attribute resource symbol scrollbarTrackHorizontal.

Related Methods

android:scrollbarTrackVertical

Defines the vertical scrollbar track drawable.

Must be a reference to another resource, in the form "@[+][package:]type:name" or to a theme attribute in the form "?[package:][type:]name".

This corresponds to the global attribute resource symbol scrollbarTrackVertical.

Related Methods

android:scrollbars

Defines which scrollbars should be displayed on scrolling or not.

Must be one or more (separated by '|') of the following constant values.

Constant	Value	Description
`none`	0x00000000	No scrollbar is displayed.
`horizontal`	0x00000100	Displays horizontal scrollbar only.
`vertical`	0x00000200	Displays vertical scrollbar only.

This corresponds to the global attribute resource symbol scrollbars.

Related Methods

android:soundEffectsEnabled

Boolean that controls whether a view should have sound effects enabled for events such as clicking and touching.

Must be a boolean value, either "true" or "false".

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

This corresponds to the global attribute resource symbol soundEffectsEnabled.

Related Methods

setSoundEffectsEnabled(boolean)

android:visibility

Controls the initial visibility of the view.

Must be one of the following constant values.

Constant	Value	Description
`visible`	0	Visible on screen; the default value.
`invisible`	1	Not displayed, but taken into account during layout (space is left for it).
`gone`	2	Completely hidden, as if the view had not been added.

This corresponds to the global attribute resource symbol visibility.

Related Methods

setVisibility(int)

Constants

public static final int DRAWING_CACHE_QUALITY_AUTO

Enables automatic quality mode for the drawing cache.

Constant Value: 0 (0x00000000)

public static final int DRAWING_CACHE_QUALITY_HIGH

Enables high quality mode for the drawing cache.

Constant Value: 1048576 (0x00100000)

public static final int DRAWING_CACHE_QUALITY_LOW

Enables low quality mode for the drawing cache.

Constant Value: 524288 (0x00080000)

protected static final int[] EMPTY_STATE_SET

Indicates the view has no states set. States are used with Drawable to change the drawing of the view depending on its state.

protected static final int[] ENABLED_FOCUSED_SELECTED_STATE_SET

Indicates the view is enabled, focused and selected.

protected static final int[] ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET

Indicates the view is enabled, focused, selected and its window has the focus.

protected static final int[] ENABLED_FOCUSED_STATE_SET

Indicates the view is enabled and has the focus.

protected static final int[] ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET

Indicates the view is enabled, focused and its window has the focus.

protected static final int[] ENABLED_SELECTED_STATE_SET

Indicates the view is enabled and selected.

protected static final int[] ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET

Indicates the view is enabled, selected and its window has the focus.

protected static final int[] ENABLED_STATE_SET

Indicates the view is enabled. States are used with Drawable to change the drawing of the view depending on its state.

protected static final int[] ENABLED_WINDOW_FOCUSED_STATE_SET

Indicates the view is enabled and that its window has focus.

protected static final int[] FOCUSED_SELECTED_STATE_SET

Indicates the view is focused and selected.

protected static final int[] FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET

Indicates the view is focused, selected and its window has the focus.

protected static final int[] FOCUSED_STATE_SET

Indicates the view is focused. States are used with Drawable to change the drawing of the view depending on its state.

protected static final int[] FOCUSED_WINDOW_FOCUSED_STATE_SET

Indicates the view has the focus and that its window has the focus.

public static final int FOCUS_BACKWARD

Use with focusSearch(int). Move focus to the previous selectable item.

Constant Value: 1 (0x00000001)

public static final int FOCUS_DOWN

Use with focusSearch(int). Move focus down.

Constant Value: 130 (0x00000082)

public static final int FOCUS_FORWARD

Use with focusSearch(int). Move focus to the next selectable item.

Constant Value: 2 (0x00000002)

public static final int FOCUS_LEFT

Use with focusSearch(int). Move focus to the left.

Constant Value: 17 (0x00000011)

public static final int FOCUS_RIGHT

Use with focusSearch(int). Move focus to the right.

Constant Value: 66 (0x00000042)

public static final int FOCUS_UP

Use with focusSearch(int). Move focus up.

Constant Value: 33 (0x00000021)

public static final int GONE

This view is invisible, and it doesn't take any space for layout purposes. Use with setVisibility(int).

Constant Value: 8 (0x00000008)

public static final int HAPTIC_FEEDBACK_ENABLED

View flag indicating whether this view should have haptic feedback enabled for events such as long presses.

Constant Value: 268435456 (0x10000000)

public static final int INVISIBLE

This view is invisible, but it still takes up space for layout purposes. Use with setVisibility(int).

Constant Value: 4 (0x00000004)

public static final int KEEP_SCREEN_ON

View flag indicating that the screen should remain on while the window containing this view is visible to the user. This effectively takes care of automatically setting the WindowManager's FLAG_KEEP_SCREEN_ON.

Constant Value: 67108864 (0x04000000)

public static final int NO_ID

Used to mark a View that has no ID.

Constant Value: -1 (0xffffffff)

protected static final int[] PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET

Indicates the view is pressed, enabled, focused and selected.

protected static final int[] PRESSED_ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET

Indicates the view is pressed, enabled, focused, selected and its window has the focus.

protected static final int[] PRESSED_ENABLED_FOCUSED_STATE_SET

Indicates the view is pressed, enabled and focused.

protected static final int[] PRESSED_ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET

Indicates the view is pressed, enabled, focused and its window has the focus.

protected static final int[] PRESSED_ENABLED_SELECTED_STATE_SET

Indicates the view is pressed, enabled and selected.

protected static final int[] PRESSED_ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET

Indicates the view is pressed, enabled, selected and its window has the focus.

protected static final int[] PRESSED_ENABLED_STATE_SET

Indicates the view is pressed and enabled.

protected static final int[] PRESSED_ENABLED_WINDOW_FOCUSED_STATE_SET

Indicates the view is pressed, enabled and its window has the focus.

protected static final int[] PRESSED_FOCUSED_SELECTED_STATE_SET

Indicates the view is pressed, focused and selected.

protected static final int[] PRESSED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET

Indicates the view is pressed, focused, selected and its window has the focus.

protected static final int[] PRESSED_FOCUSED_STATE_SET

Indicates the view is pressed and focused.

protected static final int[] PRESSED_FOCUSED_WINDOW_FOCUSED_STATE_SET

Indicates the view is pressed, focused and its window has the focus.

protected static final int[] PRESSED_SELECTED_STATE_SET

Indicates the view is pressed and selected.

protected static final int[] PRESSED_SELECTED_WINDOW_FOCUSED_STATE_SET

Indicates the view is pressed, selected and its window has the focus.

protected static final int[] PRESSED_WINDOW_FOCUSED_STATE_SET

Indicates the view is pressed and its window has the focus.

public static final int SCROLLBARS_INSIDE_INSET

The scrollbar style to display the scrollbars inside the padded area, increasing the padding of the view. The scrollbars will not overlap the content area of the view.

Constant Value: 16777216 (0x01000000)

public static final int SCROLLBARS_INSIDE_OVERLAY

The scrollbar style to display the scrollbars inside the content area, without increasing the padding. The scrollbars will be overlaid with translucency on the view's content.

Constant Value: 0 (0x00000000)

public static final int SCROLLBARS_OUTSIDE_INSET

The scrollbar style to display the scrollbars at the edge of the view, increasing the padding of the view. The scrollbars will only overlap the background, if any.

Constant Value: 50331648 (0x03000000)

public static final int SCROLLBARS_OUTSIDE_OVERLAY

The scrollbar style to display the scrollbars at the edge of the view, without increasing the padding. The scrollbars will be overlaid with translucency.

Constant Value: 33554432 (0x02000000)

protected static final int[] SELECTED_STATE_SET

Indicates the view is selected. States are used with Drawable to change the drawing of the view depending on its state.

protected static final int[] SELECTED_WINDOW_FOCUSED_STATE_SET

Indicates the view is selected and that its window has the focus.

public static final int SOUND_EFFECTS_ENABLED

View flag indicating whether this view should have sound effects enabled for events such as clicking and touching.

Constant Value: 134217728 (0x08000000)

protected static final String VIEW_LOG_TAG

The logging tag used by this class with android.util.Log.

Constant Value: "View"

public static final int VISIBLE

This view is visible. Use with setVisibility(int).

Constant Value: 0 (0x00000000)

protected static final int[] WINDOW_FOCUSED_STATE_SET

Indicates the view's window has focus. States are used with Drawable to change the drawing of the view depending on its state.

Public Constructors

public View (Context context)

Simple constructor to use when creating a view from code.

Parameters

context	The Context the view is running in, through which it can access the current theme, resources, etc.

public View (Context context, AttributeSet attrs)

Constructor that is called when inflating a view from XML. This is called when a view is being constructed from an XML file, supplying attributes that were specified in the XML file. This version uses a default style of 0, so the only attribute values applied are those in the Context's Theme and the given AttributeSet.

The method onFinishInflate() will be called after all children have been added.

Parameters

context	The Context the view is running in, through which it can access the current theme, resources, etc.
attrs	The attributes of the XML tag that is inflating the view.

public View (Context context, AttributeSet attrs, int defStyle)

Perform inflation from XML and apply a class-specific base style. This constructor of View allows subclasses to use their own base style when they are inflating. For example, a Button class's constructor would call this version of the super class constructor and supply R.attr.buttonStyle for defStyle; this allows the theme's button style to modify all of the base view attributes (in particular its background) as well as the Button class's attributes.

Parameters

context	The Context the view is running in, through which it can access the current theme, resources, etc.
attrs	The attributes of the XML tag that is inflating the view.
defStyle	The default style to apply to this view. If 0, no style will be applied (beyond what is included in the theme). This may either be an attribute resource, whose value will be retrieved from the current theme, or an explicit style resource.

Public Methods

public void addFocusables (ArrayList<View> views, int direction)

Add any focusable views that are descendants of this view (possibly including this view if it is focusable itself) to views. If we are in touch mode, only add views that are also focusable in touch mode.

Parameters

views	Focusable views found so far
direction	The direction of the focus

public void addTouchables (ArrayList<View> views)

Add any touchable views that are descendants of this view (possibly including this view if it is touchable itself) to views.

Parameters

views	Touchable views found so far

public void bringToFront ()

Change the view's z order in the tree, so it's on top of other sibling views

public void buildDrawingCache ()

Forces the drawing cache to be built if the drawing cache is invalid.

If you call buildDrawingCache() manually without calling setDrawingCacheEnabled(true), you should cleanup the cache by calling destroyDrawingCache() afterwards.

public void cancelLongPress ()

Cancels a pending long press. Your subclass can use this if you want the context menu to come up if the user presses and holds at the same place, but you don't want it to come up if they press and then move around enough to cause scrolling.

public boolean checkInputConnectionProxy (View view)

Called by the InputMethodManager when a view who is not the current input connection target is trying to make a call on the manager. The default implementation returns false; you can override this to return true for certain views if you are performing InputConnection proxying to them.

Parameters

view	The View that is making the InputMethodManager call.

Returns

Return true to allow the call, false to reject.

public void clearAnimation ()

Cancels any animations for this view.

public void clearFocus ()

Called when this view wants to give up focus. This will cause onFocusChanged(boolean, int, Rect) to be called.

public void computeScroll ()

Called by a parent to request that a child update its values for mScrollX and mScrollY if necessary. This will typically be done if the child is animating a scroll using a Scroller object.

public void createContextMenu (ContextMenu menu)

Show the context menu for this view. It is not safe to hold on to the menu after returning from this method.

Parameters

menu	The context menu to populate

public void destroyDrawingCache ()

Frees the resources used by the drawing cache. If you call buildDrawingCache() manually without calling setDrawingCacheEnabled(true), you should cleanup the cache with this method afterwards.

public boolean dispatchKeyEvent (KeyEvent event)

Dispatch a key event to the next view on the focus path. This path runs from the top of the view tree down to the currently focused view. If this view has focus, it will dispatch to itself. Otherwise it will dispatch the next node down the focus path. This method also fires any key listeners.

Parameters

event	The key event to be dispatched.

Returns

True if the event was handled, false otherwise.

public boolean dispatchKeyEventPreIme (KeyEvent event)

Dispatch a key event before it is processed by any input method associated with the view hierarchy. This can be used to intercept key events in special situations before the IME consumes them; a typical example would be handling the BACK key to update the application's UI instead of allowing the IME to see it and close itself.

Parameters

event	The key event to be dispatched.

Returns

True if the event was handled, false otherwise.

public boolean dispatchKeyShortcutEvent (KeyEvent event)

Dispatches a key shortcut event.

Parameters

event	The key event to be dispatched.

Returns

True if the event was handled by the view, false otherwise.

public boolean dispatchTouchEvent (MotionEvent event)

Pass the touch screen motion event down to the target view, or this view if it is the target.

Parameters

event	The motion event to be dispatched.

Returns

True if the event was handled by the view, false otherwise.

public boolean dispatchTrackballEvent (MotionEvent event)

Pass a trackball motion event down to the focused view.

Parameters

event	The motion event to be dispatched.

Returns

True if the event was handled by the view, false otherwise.

public boolean dispatchUnhandledMove (View focused, int direction)

This method is the last chance for the focused view and its ancestors to respond to an arrow key. This is called when the focused view did not consume the key internally, nor could the view system find a new view in the requested direction to give focus to.

Parameters

focused	The currently focused view.
direction	The direction focus wants to move. One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT.

Returns

True if the this view consumed this unhandled move.

public void dispatchWindowFocusChanged (boolean hasFocus)

Called when the window containing this view gains or loses window focus. ViewGroups should override to route to their children.

Parameters

hasFocus	True if the window containing this view now has focus, false otherwise.

public void dispatchWindowVisibilityChanged (int visibility)

Dispatch a window visibility change down the view hierarchy. ViewGroups should override to route to their children.

Parameters

visibility	The new visibility of the window.

public void draw (Canvas canvas)

Manually render this view (and all of its children) to the given Canvas. The view must have already done a full layout before this function is called. When implementing a view, do not override this method; instead, you should implement onDraw(Canvas).

Parameters

canvas	The Canvas to which the View is rendered.

public View findFocus ()

Find the view in the hierarchy rooted at this view that currently has focus.

Returns

The view that currently has focus, or null if no focused view can be found.

public final View findViewById (int id)

Look for a child view with the given id. If this view has the given id, return this view.

Parameters

id	The id to search for.

Returns

The view that has the given id in the hierarchy or null

public final View findViewWithTag (Object tag)

Look for a child view with the given tag. If this view has the given tag, return this view.

Parameters

tag	The tag to search for, using "tag.equals(getTag())".

Returns

The View that has the given tag in the hierarchy or null

public View focusSearch (int direction)

Find the nearest view in the specified direction that can take focus. This does not actually give focus to that view.

Parameters

direction	One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT

Returns

The nearest focusable in the specified direction, or null if none can be found.

public void forceLayout ()

Forces this view to be laid out during the next layout pass. This method does not call requestLayout() or forceLayout() on the parent.

public Animation getAnimation ()

Get the animation currently associated with this view.

Returns

The animation that is currently playing or scheduled to play for this view.

public IBinder getApplicationWindowToken ()

Retrieve a unique token identifying the top-level "real" window of the window that this view is attached to. That is, this is like getWindowToken(), except if the window this view in is a panel window (attached to another containing window), then the token of the containing window is returned instead.

Returns

Returns the associated window token, either getWindowToken() or the containing window's token.

public Drawable getBackground ()

Gets the background drawable

Returns

The drawable used as the background for this view, if any.

public int getBaseline ()

Return the offset of the widget's text baseline from the widget's top boundary. If this widget does not support baseline alignment, this method returns -1.

Returns

the offset of the baseline within the widget's bounds or -1 if baseline alignment is not supported

public final int getBottom ()

Bottom position of this view relative to its parent.

Returns

The bottom of this view, in pixels.

public final Context getContext ()

Returns the context the view is running in, through which it can access the current theme, resources, etc.

Returns

The view's Context.

public static int getDefaultSize (int size, int measureSpec)

Utility to return a default size. Uses the supplied size if the MeasureSpec imposed no contraints. Will get larger if allowed by the MeasureSpec.

Parameters

size	Default size for this view
measureSpec	Constraints imposed by the parent

Returns

The size this view should be.

public final int[] getDrawableState ()

Return an array of resource IDs of the drawable states representing the current state of the view.

Returns

The current drawable state

public Bitmap getDrawingCache ()

Returns the bitmap in which this view drawing is cached. The returned bitmap is null when caching is disabled. If caching is enabled and the cache is not ready, this method will create it. Calling draw(android.graphics.Canvas) will not draw from the cache when the cache is enabled. To benefit from the cache, you must request the drawing cache by calling this method and draw it on screen if the returned bitmap is not null.

Returns

a bitmap representing this view or null if cache is disabled

public int getDrawingCacheBackgroundColor ()

Returns

The background color to used for the drawing cache's bitmap

public int getDrawingCacheQuality ()

Returns the quality of the drawing cache.

Related XML Attributes

android:drawingCacheQuality

Returns

One of DRAWING_CACHE_QUALITY_AUTO, DRAWING_CACHE_QUALITY_LOW, or DRAWING_CACHE_QUALITY_HIGH

public void getDrawingRect (Rect outRect)

Return the visible drawing bounds of your view. Fills in the output rectangle with the values from getScrollX(), getScrollY(), getWidth(), and getHeight().

Parameters

outRect	The (scrolled) drawing bounds of the view.

public long getDrawingTime ()

Return the time at which the drawing of the view hierarchy started.

Returns

the drawing start time in milliseconds

public ArrayList<View> getFocusables (int direction)

Find and return all focusable views that are descendants of this view, possibly including this view if it is focusable itself.

Parameters

direction	The direction of the focus

Returns

A list of focusable views

public void getFocusedRect (Rect r)

When a view has focus and the user navigates away from it, the next view is searched for starting from the rectangle filled in by this method. By default, the rectange is the getDrawingRect(Rect))of the view. However, if your view maintains some idea of internal selection, such as a cursor, or a selected row or column, you should override this method and fill in a more specific rectangle.

Parameters

r	The rectangle to fill in, in this view's coordinates.

public boolean getGlobalVisibleRect (Rect r, Point globalOffset)

If some part of this view is not clipped by any of its parents, then return that area in r in global (root) coordinates. To convert r to local coordinates, offset it by -globalOffset (e.g. r.offset(-globalOffset.x, -globalOffset.y)) If the view is completely clipped or translated out, return false.

Parameters

r	If true is returned, r holds the global coordinates of the visible portion of this view.
globalOffset	If true is returned, globalOffset holds the dx,dy between this view and its root. globalOffet may be null.

Returns

true if r is non-empty (i.e. part of the view is visible at the root level.

public final boolean getGlobalVisibleRect (Rect r)

public Handler getHandler ()

Returns

A handler associated with the thread running the View. This handler can be used to pump events in the UI events queue.

public final int getHeight ()

Return the height of your view.

Returns

The height of your view, in pixels.

public void getHitRect (Rect outRect)

Hit rectangle in parent's coordinates

Parameters

outRect	The hit rectangle of the view.

public int getHorizontalFadingEdgeLength ()

Returns the size of the horizontal faded edges used to indicate that more content in this view is visible.

Related XML Attributes

android:fadingEdgeLength

Returns

The size in pixels of the horizontal faded edge or 0 if horizontal faded edges are not enabled for this view.

public int getId ()

Returns this view's identifier.

Related XML Attributes

android:id

Returns

a positive integer used to identify the view or NO_ID if the view has no ID

public boolean getKeepScreenOn ()

Returns whether the screen should remain on, corresponding to the current value of KEEP_SCREEN_ON.

Related XML Attributes

android:keepScreenOn

Returns

Returns true if KEEP_SCREEN_ON is set.

public ViewGroup.LayoutParams getLayoutParams ()

Get the LayoutParams associated with this view. All views should have layout parameters. These supply parameters to the parent of this view specifying how it should be arranged. There are many subclasses of ViewGroup.LayoutParams, and these correspond to the different subclasses of ViewGroup that are responsible for arranging their children.

Returns

The LayoutParams associated with this view

public final int getLeft ()

Left position of this view relative to its parent.

Returns

The left edge of this view, in pixels.

public final boolean getLocalVisibleRect (Rect r)

public void getLocationInWindow (int[] location)

Computes the coordinates of this view in its window. The argument must be an array of two integers. After the method returns, the array contains the x and y location in that order.

Parameters

location	an array of two integers in which to hold the coordinates

public void getLocationOnScreen (int[] location)

Computes the coordinates of this view on the screen. The argument must be an array of two integers. After the method returns, the array contains the x and y location in that order.

Parameters

location	an array of two integers in which to hold the coordinates

public final int getMeasuredHeight ()

The height of this view as measured in the most recent call to measure(). This should be used during measurement and layout calculations only. Use getHeight() to see how tall a view is after layout.

Returns

The measured height of this view.

public final int getMeasuredWidth ()

The width of this view as measured in the most recent call to measure(). This should be used during measurement and layout calculations only. Use getWidth() to see how wide a view is after layout.

Returns

The measured width of this view.

public int getNextFocusDownId ()

Related XML Attributes

android:nextFocusDown

Returns

The user specified next focus ID.

public int getNextFocusLeftId ()

Related XML Attributes

android:nextFocusLeft

Returns

The user specified next focus ID.

public int getNextFocusRightId ()

Related XML Attributes

android:nextFocusRight

Returns

The user specified next focus ID.

public int getNextFocusUpId ()

Related XML Attributes

android:nextFocusUp

Returns

The user specified next focus ID.

public View.OnFocusChangeListener getOnFocusChangeListener ()

Returns the focus-change callback registered for this view.

Returns

The callback, or null if one is not registered.

public int getPaddingBottom ()

Returns the bottom padding of this view. If there are inset and enabled scrollbars, this value may include the space required to display the scrollbars as well.

Returns

the bottom padding in pixels

public int getPaddingLeft ()

Returns the left padding of this view. If there are inset and enabled scrollbars, this value may include the space required to display the scrollbars as well.

Returns

the left padding in pixels

public int getPaddingRight ()

Returns the right padding of this view. If there are inset and enabled scrollbars, this value may include the space required to display the scrollbars as well.

Returns

the right padding in pixels

public int getPaddingTop ()

Returns the top padding of this view.

Returns

the top padding in pixels

public final ViewParent getParent ()

Gets the parent of this view. Note that the parent is a ViewParent and not necessarily a View.

Returns

Parent of this view.

public Resources getResources ()

Returns the resources associated with this view.

Returns

Resources object.

public final int getRight ()

Right position of this view relative to its parent.

Returns

The right edge of this view, in pixels.

public View getRootView ()

Finds the topmost view in the current view hierarchy.

Returns

the topmost view containing this view

public int getScrollBarStyle ()

Returns the current scrollbar style.

Returns

the current scrollbar style

public final int getScrollX ()

Return the scrolled left position of this view. This is the left edge of the displayed part of your view. You do not need to draw any pixels farther left, since those are outside of the frame of your view on screen.

Returns

The left edge of the displayed part of your view, in pixels.

public final int getScrollY ()

Return the scrolled top position of this view. This is the top edge of the displayed part of your view. You do not need to draw any pixels above it, since those are outside of the frame of your view on screen.

Returns

The top edge of the displayed part of your view, in pixels.

public int getSolidColor ()

Override this if your view is known to always be drawn on top of a solid color background, and needs to draw fading edges. Returning a non-zero color enables the view system to optimize the drawing of the fading edges. If you do return a non-zero color, the alpha should be set to 0xFF.

Returns

The known solid color background for this view, or 0 if the color may vary

public Object getTag ()

Returns this view's tag.

Returns

the Object stored in this view as a tag

public final int getTop ()

Top position of this view relative to its parent.

Returns

The top of this view, in pixels.

public TouchDelegate getTouchDelegate ()

Gets the TouchDelegate for this View.

public ArrayList<View> getTouchables ()

Find and return all touchable views that are descendants of this view, possibly including this view if it is touchable itself.

Returns

A list of touchable views

public int getVerticalFadingEdgeLength ()

Returns the size of the vertical faded edges used to indicate that more content in this view is visible.

Related XML Attributes

android:fadingEdgeLength

Returns

The size in pixels of the vertical faded edge or 0 if vertical faded edges are not enabled for this view.

public int getVerticalScrollbarWidth ()

Returns the width of the vertical scrollbar.

Returns

The width in pixels of the vertical scrollbar or 0 if there is no vertical scrollbar.

public ViewTreeObserver getViewTreeObserver ()

Returns the ViewTreeObserver for this view's hierarchy. The view tree observer can be used to get notifications when global events, like layout, happen. The returned ViewTreeObserver observer is not guaranteed to remain valid for the lifetime of this View. If the caller of this method keeps a long-lived reference to ViewTreeObserver, it should always check for the return value of isAlive().

Returns

The ViewTreeObserver for this view's hierarchy.

public int getVisibility ()

Returns the visibility status for this view.

Related XML Attributes

android:visibility

Returns

One of VISIBLE, INVISIBLE, or GONE.

public final int getWidth ()

Return the width of the your view.

Returns

The width of your view, in pixels.

public IBinder getWindowToken ()

Retrieve a unique token identifying the window this view is attached to.

Returns

Return the window's token for use in WindowManager.LayoutParams.token.

public int getWindowVisibility ()

Returns the current visibility of the window this view is attached to (either GONE, INVISIBLE, or VISIBLE).

Returns

Returns the current visibility of the view's window.

public void getWindowVisibleDisplayFrame (Rect outRect)

Retrieve the overall visible display size in which the window this view is attached to has been positioned in. This takes into account screen decorations above the window, for both cases where the window itself is being position inside of them or the window is being placed under then and covered insets are used for the window to position its content inside. In effect, this tells you the available area where content can be placed and remain visible to users.

This function requires an IPC back to the window manager to retrieve the requested information, so should not be used in performance critical code like drawing.

Parameters

outRect	Filled in with the visible display frame. If the view is not attached to a window, this is simply the raw display size.

public boolean hasFocus ()

Returns true if this view has focus iteself, or is the ancestor of the view that has focus.

Returns

True if this view has or contains focus, false otherwise.

public boolean hasFocusable ()

Returns true if this view is focusable or if it contains a reachable View for which hasFocusable() returns true. A "reachable hasFocusable()" is a View whose parents do not block descendants focus. Only VISIBLE views are considered focusable.

Returns

True if the view is focusable or if the view contains a focusable View, false otherwise.

public boolean hasWindowFocus ()

Returns true if this view is in a window that currently has window focus. Note that this is not the same as the view itself having focus.

Returns

True if this view is in a window that currently has window focus.

public static View inflate (Context context, int resource, ViewGroup root)

Inflate a view from an XML resource. This convenience method wraps the LayoutInflater class, which provides a full range of options for view inflation.

Parameters

context	The Context object for your activity or application.
resource	The resource ID to inflate
root	A view group that will be the parent. Used to properly inflate the layout_* parameters.

public void invalidate (int l, int t, int r, int b)

Mark the the area defined by the rect (l,t,r,b) as needing to be drawn. The coordinates of the dirty rect are relative to the view. If the view is visible, onDraw(Canvas) will be called at some point in the future. This must be called from a UI thread. To call from a non-UI thread, call postInvalidate().

Parameters

l	the left position of the dirty region
t	the top position of the dirty region
r	the right position of the dirty region
b	the bottom position of the dirty region

public void invalidate ()

Invalidate the whole view. If the view is visible, onDraw(Canvas) will be called at some point in the future. This must be called from a UI thread. To call from a non-UI thread, call postInvalidate().

public void invalidate (Rect dirty)

Mark the the area defined by dirty as needing to be drawn. If the view is visible, onDraw(Canvas) will be called at some point in the future. This must be called from a UI thread. To call from a non-UI thread, call postInvalidate(). WARNING: This method is destructive to dirty.

Parameters

dirty	the rectangle representing the bounds of the dirty region

public void invalidateDrawable (Drawable drawable)

Invalidates the specified Drawable.

Parameters

drawable	the drawable to invalidate

public boolean isClickable ()

Indicates whether this view reacts to click events or not.

Related XML Attributes

android:clickable

Returns

true if the view is clickable, false otherwise

public boolean isDrawingCacheEnabled ()

Indicates whether the drawing cache is enabled for this view.

Returns

true if the drawing cache is enabled

public boolean isDuplicateParentStateEnabled ()

Indicates whether this duplicates its drawable state from its parent.

Returns

True if this view's drawable state is duplicated from the parent, false otherwise

public boolean isEnabled ()

Returns the enabled status for this view. The interpretation of the enabled state varies by subclass.

Returns

True if this view is enabled, false otherwise.

public final boolean isFocusable ()

Returns whether this View is able to take focus.

Related XML Attributes

android:focusable

Returns

True if this view can take focus, or false otherwise.

public final boolean isFocusableInTouchMode ()

When a view is focusable, it may not want to take focus when in touch mode. For example, a button would like focus when the user is navigating via a D-pad so that the user can click on it, but once the user starts touching the screen, the button shouldn't take focus

Related XML Attributes

android:focusableInTouchMode

Returns

Whether the view is focusable in touch mode.

public boolean isFocused ()

Returns true if this view has focus

Returns

True if this view has focus, false otherwise.

public boolean isHapticFeedbackEnabled ()

Related XML Attributes

android:hapticFeedbackEnabled

Returns

whether this view should have haptic feedback enabled for events long presses.

public boolean isHorizontalFadingEdgeEnabled ()

Indicate whether the horizontal edges are faded when the view is scrolled horizontally.

Related XML Attributes

android:fadingEdge

Returns

true if the horizontal edges should are faded on scroll, false otherwise

public boolean isHorizontalScrollBarEnabled ()

Indicate whether the horizontal scrollbar should be drawn or not. The scrollbar is not drawn by default.

Returns

true if the horizontal scrollbar should be painted, false otherwise

public boolean isInEditMode ()

Indicates whether this View is currently in edit mode. A View is usually in edit mode when displayed within a developer tool. For instance, if this View is being drawn by a visual user interface builder, this method should return true. Subclasses should check the return value of this method to provide different behaviors if their normal behavior might interfere with the host environment. For instance: the class spawns a thread in its constructor, the drawing code relies on device-specific features, etc. This method is usually checked in the drawing code of custom widgets.

Returns

True if this View is in edit mode, false otherwise.

public boolean isInTouchMode ()

Returns whether the device is currently in touch mode. Touch mode is entered once the user begins interacting with the device by touch, and affects various things like whether focus is always visible to the user.

Returns

Whether the device is in touch mode.

public boolean isLayoutRequested ()

Indicates whether or not this view's layout will be requested during the next hierarchy layout pass.

Returns

true if the layout will be forced during next layout pass

public boolean isLongClickable ()

Indicates whether this view reacts to long click events or not.

Related XML Attributes

android:longClickable

Returns

true if the view is long clickable, false otherwise

public boolean isPressed ()

Indicates whether the view is currently in pressed state. Unless setPressed(boolean) is explicitly called, only clickable views can enter the pressed state.

Returns

true if the view is currently pressed, false otherwise

public boolean isSaveEnabled ()

Indicates whether this view will save its state (that is, whether its onSaveInstanceState() method will be called).

Related XML Attributes

android:saveEnabled

Returns

Returns true if the view state saving is enabled, else false.

public boolean isSelected ()

Indicates the selection state of this view.

Returns

true if the view is selected, false otherwise

public boolean isShown ()

Returns the visibility of this view and all of its ancestors

Returns

True if this view and all of its ancestors are VISIBLE

public boolean isSoundEffectsEnabled ()

Related XML Attributes

android:soundEffectsEnabled

Returns

whether this view should have sound effects enabled for events such as clicking and touching.

public boolean isVerticalFadingEdgeEnabled ()

Indicate whether the vertical edges are faded when the view is scrolled horizontally.

Related XML Attributes

android:fadingEdge

Returns

true if the vertical edges should are faded on scroll, false otherwise

public boolean isVerticalScrollBarEnabled ()

Indicate whether the vertical scrollbar should be drawn or not. The scrollbar is not drawn by default.

Returns

true if the vertical scrollbar should be painted, false otherwise

public final void layout (int l, int t, int r, int b)

Assign a size and position to a view and all of its descendants

This is the second phase of the layout mechanism. (The first is measuring). In this phase, each parent calls layout on all of its children to position them. This is typically done using the child measurements that were stored in the measure pass(). Derived classes with children should override onLayout. In that method, they should call layout on each of their their children.

Parameters

l	Left position, relative to parent
t	Top position, relative to parent
r	Right position, relative to parent
b	Bottom position, relative to parent

public final void measure (int widthMeasureSpec, int heightMeasureSpec)

This is called to find out how big a view should be. The parent supplies constraint information in the width and height parameters.

The actual mesurement work of a view is performed in onMeasure(int, int), called by this method. Therefore, only onMeasure(int, int) can and must be overriden by subclasses.

Parameters

widthMeasureSpec	Horizontal space requirements as imposed by the parent
heightMeasureSpec	Vertical space requirements as imposed by the parent

public void offsetLeftAndRight (int offset)

Offset this view's horizontal location by the specified amount of pixels.

Parameters

offset	the numer of pixels to offset the view by

public void offsetTopAndBottom (int offset)

Offset this view's vertical location by the specified number of pixels.

Parameters

offset	the number of pixels to offset the view by

public boolean onCheckIsTextEditor ()

Check whether the called view is a text editor, in which case it would make sense to automatically display a soft input window for it. Subclasses should override this if they implement onCreateInputConnection(EditorInfo) to return true if a call on that method would return a non-null InputConnection, and they are really a first-class editor that the user would normally start typing on when the go into a window containing your view.

The default implementation always returns false. This does not mean that its onCreateInputConnection(EditorInfo) will not be called or the user can not otherwise perform edits on your view; it is just a hint to the system that this is not the primary purpose of this view.

Returns

Returns true if this view is a text editor, else false.

public InputConnection onCreateInputConnection (EditorInfo outAttrs)

Create a new InputConnection for an InputMethod to interact with the view. The default implementation returns null, since it doesn't support input methods. You can override this to implement such support. This is only needed for views that take focus and text input.

When implementing this, you probably also want to implement onCheckIsTextEditor() to indicate you will return a non-null InputConnection.

Parameters

outAttrs	Fill in with attribute information about the connection.

public void onFinishTemporaryDetach ()

Called after onStartTemporaryDetach() when the container is done changing the view.

public boolean onKeyDown (int keyCode, KeyEvent event)

Default implementation of KeyEvent.Callback.onKeyMultiple(): perform press of the view when KEYCODE_DPAD_CENTER or KEYCODE_ENTER is released, if the view is enabled and clickable.

Parameters

keyCode	A key code that represents the button pressed, from KeyEvent.
event	The KeyEvent object that defines the button action.

Returns

If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

public boolean onKeyMultiple (int keyCode, int repeatCount, KeyEvent event)

Default implementation of KeyEvent.Callback.onKeyMultiple(): always returns false (doesn't handle the event).

Parameters

keyCode	A key code that represents the button pressed, from KeyEvent.
repeatCount	The number of times the action was made.
event	The KeyEvent object that defines the button action.

Returns

If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

public boolean onKeyPreIme (int keyCode, KeyEvent event)

Handle a key event before it is processed by any input method associated with the view hierarchy. This can be used to intercept key events in special situations before the IME consumes them; a typical example would be handling the BACK key to update the application's UI instead of allowing the IME to see it and close itself.

Parameters

keyCode	The value in event.getKeyCode().
event	Description of the key event.

Returns

If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

public boolean onKeyShortcut (int keyCode, KeyEvent event)

Called when an unhandled key shortcut event occurs.

Parameters

keyCode	The value in event.getKeyCode().
event	Description of the key event.

Returns

If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

public boolean onKeyUp (int keyCode, KeyEvent event)

Default implementation of KeyEvent.Callback.onKeyMultiple(): perform clicking of the view when KEYCODE_DPAD_CENTER or KEYCODE_ENTER is released.

Parameters

keyCode	A key code that represents the button pressed, from KeyEvent.
event	The KeyEvent object that defines the button action.

Returns

If you handled the event, return true. If you want to allow the event to be handled by the next receiver, return false.

public void onStartTemporaryDetach ()

This is called when a container is going to temporarily detach a child that currently has focus, with ViewGroup.detachViewFromParent. It will either be followed by onFinishTemporaryDetach() or onDetachedFromWindow() when the container is done. Generally this is currently only done ListView for a view with focus.

public boolean onTouchEvent (MotionEvent event)

Implement this method to handle touch screen motion events.

Parameters

event	The motion event.

Returns

True if the event was handled, false otherwise.

public boolean onTrackballEvent (MotionEvent event)

Implement this method to handle trackball motion events. The relative movement of the trackball since the last event can be retrieve with MotionEvent.getX() and MotionEvent.getY(). These are normalized so that a movement of 1 corresponds to the user pressing one DPAD key (so they will often be fractional values, representing the more fine-grained movement information available from a trackball).

Parameters

event	The motion event.

Returns

True if the event was handled, false otherwise.

public void onWindowFocusChanged (boolean hasWindowFocus)

Called when the window containing this view gains or loses focus. Note that this is separate from view focus: to receive key events, both your view and its window must have focus. If a window is displayed on top of yours that takes input focus, then your own window will lose focus but the view focus will remain unchanged.

Parameters

hasWindowFocus	True if the window containing this view now has focus, false otherwise.

public boolean performClick ()

Call this view's OnClickListener, if it is defined.

Returns

True there was an assigned OnClickListener that was called, false otherwise is returned.

public boolean performHapticFeedback (int feedbackConstant)

BZZZTT!!1!

Provide haptic feedback to the user for this view.

The framework will provide haptic feedback for some built in actions, such as long presses, but you may wish to provide feedback for your own widget.

The feedback will only be performed if isHapticFeedbackEnabled() is true.

Parameters

feedbackConstant	One of the constants defined in HapticFeedbackConstants

public boolean performHapticFeedback (int feedbackConstant, int flags)

BZZZTT!!1!

Like performHapticFeedback(int), with additional options.

Parameters

feedbackConstant	One of the constants defined in HapticFeedbackConstants
flags	Additional flags as per HapticFeedbackConstants.

public boolean performLongClick ()

Call this view's OnLongClickListener, if it is defined. Invokes the context menu if the OnLongClickListener did not consume the event.

Returns

True there was an assigned OnLongClickListener that was called, false otherwise is returned.

public void playSoundEffect (int soundConstant)

Play a sound effect for this view.

The framework will play sound effects for some built in actions, such as clicking, but you may wish to play these effects in your widget, for instance, for internal navigation.

The sound effect will only be played if sound effects are enabled by the user, and isSoundEffectsEnabled() is true.

Parameters

soundConstant	One of the constants defined in SoundEffectConstants

public boolean post (Runnable action)

Causes the Runnable to be added to the message queue. The runnable will be run on the user interface thread.

Parameters

action	The Runnable that will be executed.

Returns

Returns true if the Runnable was successfully placed in to the message queue. Returns false on failure, usually because the looper processing the message queue is exiting.

public boolean postDelayed (Runnable action, long delayMillis)

Causes the Runnable to be added to the message queue, to be run after the specified amount of time elapses. The runnable will be run on the user interface thread.

Parameters

action	The Runnable that will be executed.
delayMillis	The delay (in milliseconds) until the Runnable will be executed.

Returns

true if the Runnable was successfully placed in to the message queue. Returns false on failure, usually because the looper processing the message queue is exiting. Note that a result of true does not mean the Runnable will be processed -- if the looper is quit before the delivery time of the message occurs then the message will be dropped.

public void postInvalidate ()

Cause an invalidate to happen on a subsequent cycle through the event loop. Use this to invalidate the View from a non-UI thread.

public void postInvalidate (int left, int top, int right, int bottom)

Cause an invalidate of the specified area to happen on a subsequent cycle through the event loop. Use this to invalidate the View from a non-UI thread.

Parameters

left	The left coordinate of the rectangle to invalidate.
top	The top coordinate of the rectangle to invalidate.
right	The right coordinate of the rectangle to invalidate.
bottom	The bottom coordinate of the rectangle to invalidate.

public void postInvalidateDelayed (long delayMilliseconds)

Cause an invalidate to happen on a subsequent cycle through the event loop. Waits for the specified amount of time.

Parameters

delayMilliseconds	the duration in milliseconds to delay the invalidation by

public void postInvalidateDelayed (long delayMilliseconds, int left, int top, int right, int bottom)

Cause an invalidate of the specified area to happen on a subsequent cycle through the event loop. Waits for the specified amount of time.

Parameters

delayMilliseconds	the duration in milliseconds to delay the invalidation by
left	The left coordinate of the rectangle to invalidate.
top	The top coordinate of the rectangle to invalidate.
right	The right coordinate of the rectangle to invalidate.
bottom	The bottom coordinate of the rectangle to invalidate.

public void refreshDrawableState ()

Call this to force a view to update its drawable state. This will cause drawableStateChanged to be called on this view. Views that are interested in the new state should call getDrawableState.

public boolean removeCallbacks (Runnable action)

Removes the specified Runnable from the message queue.

Parameters

action	The Runnable to remove from the message handling queue

Returns

true if this view could ask the Handler to remove the Runnable, false otherwise. When the returned value is true, the Runnable may or may not have been actually removed from the message queue (for instance, if the Runnable was not in the queue already.)

public final boolean requestFocus ()

Call this to try to give focus to a specific view or to one of its descendants. A view will not actually take focus if it is not focusable (isFocusable() returns false), or if it is focusable and it is not focusable in touch mode (isFocusableInTouchMode()) while the device is in touch mode. See also focusSearch(int), which is what you call to say that you have focus, and you want your parent to look for the next one. This is equivalent to calling requestFocus(int, Rect) with arguments FOCUS_DOWN and null.

Returns

Whether this view or one of its descendants actually took focus.

public boolean requestFocus (int direction, Rect previouslyFocusedRect)

Call this to try to give focus to a specific view or to one of its descendants and give it hints about the direction and a specific rectangle that the focus is coming from. The rectangle can help give larger views a finer grained hint about where focus is coming from, and therefore, where to show selection, or forward focus change internally. A view will not actually take focus if it is not focusable (isFocusable() returns false), or if it is focusable and it is not focusable in touch mode (isFocusableInTouchMode()) while the device is in touch mode. A View will not take focus if it is not visible. A View will not take focus if one of its parents has getDescendantFocusability() equal to FOCUS_BLOCK_DESCENDANTS. See also focusSearch(int), which is what you call to say that you have focus, and you want your parent to look for the next one. You may wish to override this method if your custom View has an internal View that it wishes to forward the request to.

Parameters

direction	One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT
previouslyFocusedRect	The rectangle (in this View's coordinate system) to give a finer grained hint about where focus is coming from. May be null if there is no hint.

Returns

Whether this view or one of its descendants actually took focus.

public final boolean requestFocus (int direction)

Call this to try to give focus to a specific view or to one of its descendants and give it a hint about what direction focus is heading. A view will not actually take focus if it is not focusable (isFocusable() returns false), or if it is focusable and it is not focusable in touch mode (isFocusableInTouchMode()) while the device is in touch mode. See also focusSearch(int), which is what you call to say that you have focus, and you want your parent to look for the next one. This is equivalent to calling requestFocus(int, Rect) with null set for the previously focused rectangle.

Parameters

direction	One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT

Returns

Whether this view or one of its descendants actually took focus.

public final boolean requestFocusFromTouch ()

Call this to try to give focus to a specific view or to one of its descendants. This is a special variant of requestFocus() that will allow views that are not focuable in touch mode to request focus when they are touched.

Returns

Whether this view or one of its descendants actually took focus.

public void requestLayout ()

Call this when something has changed which has invalidated the layout of this view. This will schedule a layout pass of the view tree.

public boolean requestRectangleOnScreen (Rect rectangle, boolean immediate)

Request that a rectangle of this view be visible on the screen, scrolling if necessary just enough.

A View should call this if it maintains some notion of which part of its content is interesting. For example, a text editing view should call this when its cursor moves.

When immediate is set to true, scrolling will not be animated.

Parameters

rectangle	The rectangle.
immediate	True to forbid animated scrolling, false otherwise

Returns

Whether any parent scrolled.

public boolean requestRectangleOnScreen (Rect rectangle)

Request that a rectangle of this view be visible on the screen, scrolling if necessary just enough.

A View should call this if it maintains some notion of which part of its content is interesting. For example, a text editing view should call this when its cursor moves.

Parameters

rectangle	The rectangle.

Returns

Whether any parent scrolled.

public static int resolveSize (int size, int measureSpec)

Utility to reconcile a desired size with constraints imposed by a MeasureSpec. Will take the desired size, unless a different size is imposed by the constraints.

Parameters

size	How big the view wants to be
measureSpec	Constraints imposed by the parent

Returns

The size this view should be.

public void restoreHierarchyState (SparseArray<Parcelable> container)

Restore this view hierarchy's frozen state from the given container.

Parameters

container	The SparseArray which holds previously frozen states.

public void saveHierarchyState (SparseArray<Parcelable> container)

Store this view hierarchy's frozen state into the given container.

Parameters

container	The SparseArray in which to save the view's state.

public void scheduleDrawable (Drawable who, Runnable what, long when)

Schedules an action on a drawable to occur at a specified time.

Parameters

who	the recipient of the action
what	the action to run on the drawable
when	the time at which the action must occur. Uses the uptimeMillis() timebase.

public void scrollBy (int x, int y)

Move the scrolled position of your view. This will cause a call to onScrollChanged(int, int, int, int) and the view will be invalidated.

Parameters

x	the amount of pixels to scroll by horizontally
y	the amount of pixels to scroll by vertically

public void scrollTo (int x, int y)

Set the scrolled position of your view. This will cause a call to onScrollChanged(int, int, int, int) and the view will be invalidated.

Parameters

x	the x position to scroll to
y	the y position to scroll to

public void setAnimation (Animation animation)

Sets the next animation to play for this view. If you want the animation to play immediately, use startAnimation. This method provides allows fine-grained control over the start time and invalidation, but you must make sure that 1) the animation has a start time set, and 2) the view will be invalidated when the animation is supposed to start.

Parameters

animation	The next animation, or null.

public void setBackgroundColor (int color)

Sets the background color for this view.

Parameters

color	the color of the background

public void setBackgroundDrawable (Drawable d)

Set the background to a given Drawable, or remove the background. If the background has padding, this View's padding is set to the background's padding. However, when a background is removed, this View's padding isn't touched. If setting the padding is desired, please use setPadding(int, int, int, int).

Parameters

d	The Drawable to use as the background, or null to remove the background

public void setBackgroundResource (int resid)

Set the background to a given resource. The resource should refer to a Drawable object.

Related XML Attributes

android:background

Parameters

resid	The identifier of the resource.

public void setClickable (boolean clickable)

Enables or disables click events for this view. When a view is clickable it will change its state to "pressed" on every click. Subclasses should set the view clickable to visually react to user's clicks.

Related XML Attributes

android:clickable

Parameters

clickable	true to make the view clickable, false otherwise

public void setDrawingCacheBackgroundColor (int color)

Setting a solid background color for the drawing cache's bitmaps will improve perfromance and memory usage. Note, though that this should only be used if this view will always be drawn on top of a solid color.

Parameters

color	The background color to use for the drawing cache's bitmap

public void setDrawingCacheEnabled (boolean enabled)

Enables or disables the drawing cache. When the drawing cache is enabled, the next call to getDrawingCache() or buildDrawingCache() will draw the view in a bitmap. Calling draw(android.graphics.Canvas) will not draw from the cache when the cache is enabled. To benefit from the cache, you must request the drawing cache by calling getDrawingCache() and draw it on screen if the returned bitmap is not null.

Parameters

enabled	true to enable the drawing cache, false otherwise

public void setDrawingCacheQuality (int quality)

Set the drawing cache quality of this view. This value is used only when the drawing cache is enabled

Related XML Attributes

android:drawingCacheQuality

Parameters

quality	One of DRAWING_CACHE_QUALITY_AUTO, DRAWING_CACHE_QUALITY_LOW, or DRAWING_CACHE_QUALITY_HIGH

public void setDuplicateParentStateEnabled (boolean enabled)

Enables or disables the duplication of the parent's state into this view. When duplication is enabled, this view gets its drawable state from its parent rather than from its own internal properties.

Note: in the current implementation, setting this property to true after the view was added to a ViewGroup might have no effect at all. This property should always be used from XML or set to true before adding this view to a ViewGroup.

Note: if this view's parent addStateFromChildren property is enabled and this property is enabled, an exception will be thrown.

Parameters

enabled	True to enable duplication of the parent's drawable state, false to disable it.

public void setEnabled (boolean enabled)

Set the enabled state of this view. The interpretation of the enabled state varies by subclass.

Parameters

enabled	True if this view is enabled, false otherwise.

public void setFadingEdgeLength (int length)

Set the size of the faded edge used to indicate that more content in this view is available. Will not change whether the fading edge is enabled; use setVerticalFadingEdgeEnabled(boolean) or setHorizontalFadingEdgeEnabled(boolean) to enable the fading edge for the vertical or horizontal fading edges.

Parameters

length	The size in pixels of the faded edge used to indicate that more content in this view is visible.

public void setFocusable (boolean focusable)

Set whether this view can receive the focus. Setting this to false will also ensure that this view is not focusable in touch mode.

Related XML Attributes

android:focusable

Parameters

focusable	If true, this view can receive the focus.

public void setFocusableInTouchMode (boolean focusableInTouchMode)

Set whether this view can receive focus while in touch mode. Setting this to true will also ensure that this view is focusable.

Related XML Attributes

android:focusableInTouchMode

Parameters

focusableInTouchMode	If true, this view can receive the focus while in touch mode.

public void setHapticFeedbackEnabled (boolean hapticFeedbackEnabled)

Set whether this view should have haptic feedback for events such as long presses.

You may wish to disable haptic feedback if your view already controls its own haptic feedback.

Related XML Attributes

android:hapticFeedbackEnabled

Parameters

hapticFeedbackEnabled	whether haptic feedback enabled for this view.

public void setHorizontalFadingEdgeEnabled (boolean horizontalFadingEdgeEnabled)

Define whether the horizontal edges should be faded when this view is scrolled horizontally.

Related XML Attributes

android:fadingEdge

Parameters

horizontalFadingEdgeEnabled	true if the horizontal edges should be faded when the view is scrolled horizontally

public void setHorizontalScrollBarEnabled (boolean horizontalScrollBarEnabled)

Define whether the horizontal scrollbar should be drawn or not. The scrollbar is not drawn by default.

Parameters

horizontalScrollBarEnabled	true if the horizontal scrollbar should be painted

public void setId (int id)

Sets the identifier for this view. The identifier does not have to be unique in this view's hierarchy. The identifier should be a positive number.

Related XML Attributes

android:id

Parameters

id	a number used to identify the view

public void setKeepScreenOn (boolean keepScreenOn)

Controls whether the screen should remain on, modifying the value of KEEP_SCREEN_ON.

Related XML Attributes

android:keepScreenOn

Parameters

keepScreenOn	Supply true to set KEEP_SCREEN_ON.

public void setLayoutParams (ViewGroup.LayoutParams params)

Set the layout parameters associated with this view. These supply parameters to the parent of this view specifying how it should be arranged. There are many subclasses of ViewGroup.LayoutParams, and these correspond to the different subclasses of ViewGroup that are responsible for arranging their children.

Parameters

params	the layout parameters for this view

public void setLongClickable (boolean longClickable)

Enables or disables long click events for this view. When a view is long clickable it reacts to the user holding down the button for a longer duration than a tap. This event can either launch the listener or a context menu.

Related XML Attributes

android:longClickable

Parameters

longClickable	true to make the view long clickable, false otherwise

public void setMinimumHeight (int minHeight)

Sets the minimum height of the view. It is not guaranteed the view will be able to achieve this minimum height (for example, if its parent layout constrains it with less available height).

Parameters

minHeight	The minimum height the view will try to be.

public void setMinimumWidth (int minWidth)

Sets the minimum width of the view. It is not guaranteed the view will be able to achieve this minimum width (for example, if its parent layout constrains it with less available width).

Parameters

minWidth	The minimum width the view will try to be.

public void setNextFocusDownId (int nextFocusDownId)

Set the id of the view to use for the next focus

Related XML Attributes

android:nextFocusDown

public void setNextFocusLeftId (int nextFocusLeftId)

Set the id of the view to use for the next focus

Related XML Attributes

android:nextFocusLeft

public void setNextFocusRightId (int nextFocusRightId)

Set the id of the view to use for the next focus

Related XML Attributes

android:nextFocusRight

public void setNextFocusUpId (int nextFocusUpId)

Set the id of the view to use for the next focus

Related XML Attributes

android:nextFocusUp

public void setOnClickListener (View.OnClickListener l)

Register a callback to be invoked when this view is clicked. If this view is not clickable, it becomes clickable.

Parameters

l	The callback that will run

public void setOnCreateContextMenuListener (View.OnCreateContextMenuListener l)

Register a callback to be invoked when the context menu for this view is being built. If this view is not long clickable, it becomes long clickable.

Parameters

l	The callback that will run

public void setOnFocusChangeListener (View.OnFocusChangeListener l)

Register a callback to be invoked when focus of this view changed.

Parameters

l	The callback that will run.

public void setOnKeyListener (View.OnKeyListener l)

Register a callback to be invoked when a key is pressed in this view.

Parameters

l	the key listener to attach to this view

public void setOnLongClickListener (View.OnLongClickListener l)

Register a callback to be invoked when this view is clicked and held. If this view is not long clickable, it becomes long clickable.

Parameters

l	The callback that will run

public void setOnTouchListener (View.OnTouchListener l)

Register a callback to be invoked when a touch event is sent to this view.

Parameters

l	the touch listener to attach to this view

public void setPadding (int left, int top, int right, int bottom)

Sets the padding. The view may add on the space required to display the scrollbars, depending on the style and visibility of the scrollbars. So the values returned from getPaddingLeft(), getPaddingTop(), getPaddingRight() and getPaddingBottom() may be different from the values set in this call.

Related XML Attributes

Parameters

left	the left padding in pixels
top	the top padding in pixels
right	the right padding in pixels
bottom	the bottom padding in pixels

public void setPressed (boolean pressed)

Sets the pressed that for this view.

Parameters

pressed	Pass true to set the View's internal state to "pressed", or false to reverts the View's internal state from a previously set "pressed" state.

public void setSaveEnabled (boolean enabled)

Controls whether the saving of this view's state is enabled (that is, whether its onSaveInstanceState() method will be called). Note that even if freezing is enabled, the view still must have an id assigned to it (via setId()) for its state to be saved. This flag can only disable the saving of this view; any child views may still have their state saved.

Related XML Attributes

android:saveEnabled

Parameters

enabled	Set to false to disable state saving, or true (the default) to allow it.

public void setScrollBarStyle (int style)

Specify the style of the scrollbars. The scrollbars can be overlaid or inset. When inset, they add to the padding of the view. And the scrollbars can be drawn inside the padding area or on the edge of the view. For example, if a view has a background drawable and you want to draw the scrollbars inside the padding specified by the drawable, you can use SCROLLBARS_INSIDE_OVERLAY or SCROLLBARS_INSIDE_INSET. If you want them to appear at the edge of the view, ignoring the padding, then you can use SCROLLBARS_OUTSIDE_OVERLAY or SCROLLBARS_OUTSIDE_INSET.

Parameters

style	the style of the scrollbars. Should be one of SCROLLBARS_INSIDE_OVERLAY, SCROLLBARS_INSIDE_INSET, SCROLLBARS_OUTSIDE_OVERLAY or SCROLLBARS_OUTSIDE_INSET.

public void setScrollContainer (boolean isScrollContainer)

Change whether this view is one of the set of scrollable containers in its window. This will be used to determine whether the window can resize or must pan when a soft input area is open -- scrollable containers allow the window to use resize mode since the container will appropriately shrink.

public void setSelected (boolean selected)

Changes the selection state of this view. A view can be selected or not. Note that selection is not the same as focus. Views are typically selected in the context of an AdapterView like ListView or GridView; the selected view is the view that is highlighted.

Parameters

selected	true if the view must be selected, false otherwise

public void setSoundEffectsEnabled (boolean soundEffectsEnabled)

Set whether this view should have sound effects enabled for events such as clicking and touching.

You may wish to disable sound effects for a view if you already play sounds, for instance, a dial key that plays dtmf tones.

Related XML Attributes

android:soundEffectsEnabled

Parameters

soundEffectsEnabled	whether sound effects are enabled for this view.

public void setTag (Object tag)

Sets the tag associated with this view. A tag can be used to mark a view in its hierarchy and does not have to be unique within the hierarchy. Tags can also be used to store data within a view without resorting to another data structure.

Parameters

tag	an Object to tag the view with

public void setTouchDelegate (TouchDelegate delegate)

Sets the TouchDelegate for this View.

public void setVerticalFadingEdgeEnabled (boolean verticalFadingEdgeEnabled)

Define whether the vertical edges should be faded when this view is scrolled vertically.

Related XML Attributes

android:fadingEdge

Parameters

verticalFadingEdgeEnabled	true if the vertical edges should be faded when the view is scrolled vertically

public void setVerticalScrollBarEnabled (boolean verticalScrollBarEnabled)

Define whether the vertical scrollbar should be drawn or not. The scrollbar is not drawn by default.

Parameters

verticalScrollBarEnabled	true if the vertical scrollbar should be painted

public void setVisibility (int visibility)

Set the enabled state of this view.

Related XML Attributes

android:visibility

Parameters

visibility	One of VISIBLE, INVISIBLE, or GONE.

public void setWillNotCacheDrawing (boolean willNotCacheDrawing)

When a View's drawing cache is enabled, drawing is redirected to an offscreen bitmap. Some views, like an ImageView, must be able to bypass this mechanism if they already draw a single bitmap, to avoid unnecessary usage of the memory.

Parameters

willNotCacheDrawing	true if this view does not cache its drawing, false otherwise

public void setWillNotDraw (boolean willNotDraw)

If this view doesn't do any drawing on its own, set this flag to allow further optimizations. By default, this flag is not set on View, but could be set on some View subclasses such as ViewGroup. Typically, if you override onDraw(Canvas) you should clear this flag.

Parameters

willNotDraw	whether or not this View draw on its own

public boolean showContextMenu ()

Bring up the context menu for this view.

Returns

Whether a context menu was displayed.

public void startAnimation (Animation animation)

Start the specified animation now.

Parameters

animation	the animation to start now

public void unscheduleDrawable (Drawable who, Runnable what)

Cancels a scheduled action on a drawable.

Parameters

who	the recipient of the action
what	the action to cancel

public void unscheduleDrawable (Drawable who)

Unschedule any events associated with the given Drawable. This can be used when selecting a new Drawable into a view, so that the previous one is completely unscheduled.

Parameters

who	The Drawable to unschedule.

public boolean willNotCacheDrawing ()

Returns whether or not this View can cache its drawing or not.

Returns

true if this view does not cache its drawing, false otherwise

public boolean willNotDraw ()

Returns whether or not this View draws on its own.

Returns

true if this view has nothing to draw, false otherwise

Protected Methods

protected int computeHorizontalScrollExtent ()

Compute the horizontal extent of the horizontal scrollbar's thumb within the horizontal range. This value is used to compute the length of the thumb within the scrollbar's track.

The range is expressed in arbitrary units that must be the same as the units used by computeHorizontalScrollRange() and computeHorizontalScrollOffset().

The default extent is the drawing width of this view.

Returns

the horizontal extent of the scrollbar's thumb

protected int computeHorizontalScrollOffset ()

Compute the horizontal offset of the horizontal scrollbar's thumb within the horizontal range. This value is used to compute the position of the thumb within the scrollbar's track.

The range is expressed in arbitrary units that must be the same as the units used by computeHorizontalScrollRange() and computeHorizontalScrollExtent().

The default offset is the scroll offset of this view.

Returns

the horizontal offset of the scrollbar's thumb

protected int computeHorizontalScrollRange ()

Compute the horizontal range that the horizontal scrollbar represents.

The range is expressed in arbitrary units that must be the same as the units used by computeHorizontalScrollExtent() and computeHorizontalScrollOffset().

The default range is the drawing width of this view.

Returns

the total horizontal range represented by the horizontal scrollbar

protected int computeVerticalScrollExtent ()

Compute the vertical extent of the horizontal scrollbar's thumb within the vertical range. This value is used to compute the length of the thumb within the scrollbar's track.

The range is expressed in arbitrary units that must be the same as the units used by computeHorizontalScrollRange() and computeVerticalScrollOffset().

The default extent is the drawing height of this view.

Returns

the vertical extent of the scrollbar's thumb

protected int computeVerticalScrollOffset ()

Compute the vertical offset of the vertical scrollbar's thumb within the horizontal range. This value is used to compute the position of the thumb within the scrollbar's track.

The range is expressed in arbitrary units that must be the same as the units used by computeVerticalScrollRange() and computeVerticalScrollExtent().

The default offset is the scroll offset of this view.

Returns

the vertical offset of the scrollbar's thumb

protected int computeVerticalScrollRange ()

Compute the vertical range that the vertical scrollbar represents.

The range is expressed in arbitrary units that must be the same as the units used by computeVerticalScrollExtent() and computeVerticalScrollOffset().

Returns

the total vertical range represented by the vertical scrollbar
The default range is the drawing height of this view.

protected void dispatchDraw (Canvas canvas)

Called by draw to draw the child views. This may be overridden by derived classes to gain control just before its children are drawn (but after its own view has been drawn).

Parameters

canvas	the canvas on which to draw the view

protected void dispatchRestoreInstanceState (SparseArray<Parcelable> container)

Called by restoreHierarchyState(SparseArray) to retrieve the state for this view and its children. May be overridden to modify how restoreing happens to a view's children; for example, some views may want to not store state for their children.

Parameters

container	The SparseArray which holds previously saved state.

protected void dispatchSaveInstanceState (SparseArray<Parcelable> container)

Called by saveHierarchyState(SparseArray) to store the state for this view and its children. May be overridden to modify how freezing happens to a view's children; for example, some views may want to not store state for their children.

Parameters

container	The SparseArray in which to save the view's state.

protected void dispatchSetPressed (boolean pressed)

Dispatch setPressed to all of this View's children.

Parameters

pressed	The new pressed state

protected void dispatchSetSelected (boolean selected)

Dispatch setSelected to all of this View's children.

Parameters

selected	The new selected state

protected void drawableStateChanged ()

This function is called whenever the state of the view changes in such a way that it impacts the state of drawables being shown.

Be sure to call through to the superclass when overriding this function.

protected void finalize ()

Is called before the object's memory is being reclaimed by the VM. This can only happen once the VM has detected, during a run of the garbage collector, that the object is no longer reachable by any thread of the running application.

The method can be used to free system resources or perform other cleanup before the object is garbage collected. The default implementation of the method is empty, which is also expected by the VM, but subclasses can override finalize() as required. Uncaught exceptions which are thrown during the execution of this method cause it to terminate immediately but are otherwise ignored.

Note that the VM does guarantee that finalize() is called at most once for any object, but it doesn't guarantee when (if at all) finalize() will be called. For example, object B's finalize() can delay the execution of object A's finalize() method and therefore it can delay the reclamation of A's memory. To be safe, use a ReferenceQueue, because it provides more control over the way the VM deals with references during garbage collection.

Throws

Throwable

protected boolean fitSystemWindows (Rect insets)

Apply the insets for system windows to this view, if the FITS_SYSTEM_WINDOWS flag is set

Parameters

insets	Insets for system windows

Returns

True if this view applied the insets, false otherwise

protected float getBottomFadingEdgeStrength ()

Returns the strength, or intensity, of the bottom faded edge. The strength is a value between 0.0 (no fade) and 1.0 (full fade). The default implementation returns 0.0 or 1.0 but no value in between. Subclasses should override this method to provide a smoother fade transition when scrolling occurs.

Returns

the intensity of the bottom fade as a float between 0.0f and 1.0f

protected int getBottomPaddingOffset ()

Amount by which to extend the bottom fading region. Called only when isPaddingOffsetRequired() returns true.

Returns

The bottom padding offset in pixels.

protected ContextMenu.ContextMenuInfo getContextMenuInfo ()

Views should implement this if they have extra information to associate with the context menu. The return result is supplied as a parameter to the onCreateContextMenu(ContextMenu, View, ContextMenuInfo) callback.

Returns

Extra information about the item for which the context menu should be shown. This information will vary across different subclasses of View.

protected int getHorizontalScrollbarHeight ()

Returns the height of the horizontal scrollbar.

Returns

The height in pixels of the horizontal scrollbar or 0 if there is no horizontal scrollbar.

protected float getLeftFadingEdgeStrength ()

Returns the strength, or intensity, of the left faded edge. The strength is a value between 0.0 (no fade) and 1.0 (full fade). The default implementation returns 0.0 or 1.0 but no value in between. Subclasses should override this method to provide a smoother fade transition when scrolling occurs.

Returns

the intensity of the left fade as a float between 0.0f and 1.0f

protected int getLeftPaddingOffset ()

Amount by which to extend the left fading region. Called only when isPaddingOffsetRequired() returns true.

Returns

The left padding offset in pixels.

protected float getRightFadingEdgeStrength ()

Returns the strength, or intensity, of the right faded edge. The strength is a value between 0.0 (no fade) and 1.0 (full fade). The default implementation returns 0.0 or 1.0 but no value in between. Subclasses should override this method to provide a smoother fade transition when scrolling occurs.

Returns

the intensity of the right fade as a float between 0.0f and 1.0f

protected int getRightPaddingOffset ()

Amount by which to extend the right fading region. Called only when isPaddingOffsetRequired() returns true.

Returns

The right padding offset in pixels.

protected int getSuggestedMinimumHeight ()

Returns the suggested minimum height that the view should use. This returns the maximum of the view's minimum height and the background's minimum height (getMinimumHeight()).

When being used in onMeasure(int, int), the caller should still ensure the returned height is within the requirements of the parent.

Returns

The suggested minimum height of the view.

protected int getSuggestedMinimumWidth ()

Returns the suggested minimum width that the view should use. This returns the maximum of the view's minimum width) and the background's minimum width (getMinimumWidth()).

When being used in onMeasure(int, int), the caller should still ensure the returned width is within the requirements of the parent.

Returns

The suggested minimum width of the view.

protected float getTopFadingEdgeStrength ()

Returns the strength, or intensity, of the top faded edge. The strength is a value between 0.0 (no fade) and 1.0 (full fade). The default implementation returns 0.0 or 1.0 but no value in between. Subclasses should override this method to provide a smoother fade transition when scrolling occurs.

Returns

the intensity of the top fade as a float between 0.0f and 1.0f

protected int getTopPaddingOffset ()

Amount by which to extend the top fading region. Called only when isPaddingOffsetRequired() returns true.

Returns

The top padding offset in pixels.

protected int getWindowAttachCount ()

Returns

The number of times this view has been attached to a window

protected void initializeFadingEdge (TypedArray a)

Initializes the fading edges from a given set of styled attributes. This method should be called by subclasses that need fading edges and when an instance of these subclasses is created programmatically rather than being inflated from XML. This method is automatically called when the XML is inflated.

Parameters

a	the styled attributes set to initialize the fading edges from

protected void initializeScrollbars (TypedArray a)

Initializes the scrollbars from a given set of styled attributes. This method should be called by subclasses that need scrollbars and when an instance of these subclasses is created programmatically rather than being inflated from XML. This method is automatically called when the XML is inflated.

Parameters

a	the styled attributes set to initialize the scrollbars from

protected boolean isPaddingOffsetRequired ()

If the View draws content inside its padding and enables fading edges, it needs to support padding offsets. Padding offsets are added to the fading edges to extend the length of the fade so that it covers pixels drawn inside the padding. Subclasses of this class should override this method if they need to draw content inside the padding.

Returns

True if padding offset must be applied, false otherwise.

protected static int[] mergeDrawableStates (int[] baseState, int[] additionalState)

Merge your own state values in additionalState into the base state values baseState that were returned by onCreateDrawableState(int).

Parameters

baseState	The base state values returned by onCreateDrawableState(int), which will be modified to also hold your own additional state values.
additionalState	The additional state values you would like added to `baseState`; this array is not modified.

Returns

As a convenience, the baseState array you originally passed into the function is returned.

protected void onAnimationEnd ()

Invoked by a parent ViewGroup to notify the end of the animation currently associated with this view. If you override this method, always call super.onAnimationEnd();

protected void onAnimationStart ()

Invoked by a parent ViewGroup to notify the start of the animation currently associated with this view. If you override this method, always call super.onAnimationStart();

protected void onAttachedToWindow ()

This is called when the view is attached to a window. At this point it has a Surface and will start drawing. Note that this function is guaranteed to be called before onDraw(Canvas), however it may be called any time before the first onDraw -- including before or after onMeasure(int, int).

protected void onCreateContextMenu (ContextMenu menu)

Views should implement this if the view itself is going to add items to the context menu.

Parameters

menu	the context menu to populate

protected int[] onCreateDrawableState (int extraSpace)

Generate the new Drawable state for this view. This is called by the view system when the cached Drawable state is determined to be invalid. To retrieve the current state, you should use getDrawableState().

Parameters

extraSpace	if non-zero, this is the number of extra entries you would like in the returned array in which you can place your own states.

Returns

Returns an array holding the current Drawable state of the view.

protected void onDetachedFromWindow ()

This is called when the view is detached from a window. At this point it no longer has a surface for drawing.

protected void onDraw (Canvas canvas)

Implement this to do your drawing.

Parameters

canvas	the canvas on which the background will be drawn

protected void onFinishInflate ()

Finalize inflating a view from XML. This is called as the last phase of inflation, after all child views have been added.

Even if the subclass overrides onFinishInflate, they should always be sure to call the super method, so that we get called.

protected void onFocusChanged (boolean gainFocus, int direction, Rect previouslyFocusedRect)

Called by the view system when the focus state of this view changes. When the focus change event is caused by directional navigation, direction and previouslyFocusedRect provide insight into where the focus is coming from. When overriding, be sure to call up through to the super class so that the standard focus handling will occur.

Parameters

gainFocus	True if the View has focus; false otherwise.
direction	The direction focus has moved when requestFocus() is called to give this view focus. Values are View.FOCUS_UP, View.FOCUS_DOWN, View.FOCUS_LEFT or View.FOCUS_RIGHT. It may not always apply, in which case use the default.
previouslyFocusedRect	The rectangle, in this view's coordinate system, of the previously focused view. If applicable, this will be passed in as finer grained information about where the focus is coming from (in addition to direction). Will be `null` otherwise.

protected void onLayout (boolean changed, int left, int top, int right, int bottom)

Called from layout when this view should assign a size and position to each of its children. Derived classes with children should override this method and call layout on each of their their children.

Parameters

changed	This is a new size or position for this view
left	Left position, relative to parent
top	Top position, relative to parent
right	Right position, relative to parent
bottom	Bottom position, relative to parent

protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)

Measure the view and its content to determine the measured width and the measured height. This method is invoked by measure(int, int) and should be overriden by subclasses to provide accurate and efficient measurement of their contents.

CONTRACT: When overriding this method, you must call setMeasuredDimension(int, int) to store the measured width and height of this view. Failure to do so will trigger an IllegalStateException, thrown by measure(int, int). Calling the superclass' onMeasure(int, int) is a valid use.

The base class implementation of measure defaults to the background size, unless a larger size is allowed by the MeasureSpec. Subclasses should override onMeasure(int, int) to provide better measurements of their content.

If this method is overridden, it is the subclass's responsibility to make sure the measured height and width are at least the view's minimum height and width (getSuggestedMinimumHeight() and getSuggestedMinimumWidth()).

Parameters

widthMeasureSpec	horizontal space requirements as imposed by the parent. The requirements are encoded with View.MeasureSpec.
heightMeasureSpec	vertical space requirements as imposed by the parent. The requirements are encoded with View.MeasureSpec.

protected void onRestoreInstanceState (Parcelable state)

Hook allowing a view to re-apply a representation of its internal state that had previously been generated by onSaveInstanceState(). This function will never be called with a null state.

Parameters

state	The frozen state that had previously been returned by onSaveInstanceState().

protected Parcelable onSaveInstanceState ()

Hook allowing a view to generate a representation of its internal state that can later be used to create a new instance with that same state. This state should only contain information that is not persistent or can not be reconstructed later. For example, you will never store your current position on screen because that will be computed again when a new instance of the view is placed in its view hierarchy.

Some examples of things you may store here: the current cursor position in a text view (but usually not the text itself since that is stored in a content provider or other persistent storage), the currently selected item in a list view.

Returns

Returns a Parcelable object containing the view's current dynamic state, or null if there is nothing interesting to save. The default implementation returns null.

protected void onScrollChanged (int l, int t, int oldl, int oldt)

This is called in response to an internal scroll in this view (i.e., the view scrolled its own contents). This is typically as a result of scrollBy(int, int) or scrollTo(int, int) having been called.

Parameters

l	Current horizontal scroll origin.
t	Current vertical scroll origin.
oldl	Previous horizontal scroll origin.
oldt	Previous vertical scroll origin.

protected boolean onSetAlpha (int alpha)

Invoked if there is a Transform that involves alpha. Subclass that can draw themselves with the specified alpha should return true, and then respect that alpha when their onDraw() is called. If this returns false then the view may be redirected to draw into an offscreen buffer to fulfill the request, which will look fine, but may be slower than if the subclass handles it internally. The default implementation returns false.

Parameters

alpha	The alpha (0..255) to apply to the view's drawing

Returns

true if the view can draw with the specified alpha.

protected void onSizeChanged (int w, int h, int oldw, int oldh)

This is called during layout when the size of this view has changed. If you were just added to the view hierarchy, you're called with the old values of 0.

Parameters

w	Current width of this view.
h	Current height of this view.
oldw	Old width of this view.
oldh	Old height of this view.

protected void onWindowVisibilityChanged (int visibility)

Called when the window containing has change its visibility (between GONE, INVISIBLE, and VISIBLE). Note that this tells you whether or not your window is being made visible to the window manager; this does not tell you whether or not your window is obscured by other windows on the screen, even if it is itself visible.

Parameters

visibility	The new visibility of the window.

protected final void setMeasuredDimension (int measuredWidth, int measuredHeight)

This mehod must be called by onMeasure(int, int) to store the measured width and measured height. Failing to do so will trigger an exception at measurement time.

Parameters

measuredWidth	the measured width of this view
measuredHeight	the measured height of this view

protected boolean verifyDrawable (Drawable who)

If your view subclass is displaying its own Drawable objects, it should override this function and return true for any Drawable it is displaying. This allows animations for those drawables to be scheduled.

Be sure to call through to the super class when overriding this function.

Parameters

who	The Drawable to verify. Return true if it is one you are displaying, else return the result of calling through to the super class.

Returns

boolean If true than the Drawable is being displayed in the view; else false and it is not allowed to animate.

Interfaces

Classes

Enums

Exceptions

View

Class Overview

Using Views

Implementing a Custom View

IDs

Position

Size, padding and margins

Layout

Drawing

Event Handling and Threading

Focus Handling

Touch Mode

Scrolling

Tags

Animation

See Also

Summary

XML Attributes

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