java.lang.Object | ||
↳ | android.graphics.drawable.Drawable | |
↳ | android.graphics.drawable.LayerDrawable |
Known Direct Subclasses |
A Drawable that manages an array of other Drawables. These are drawn in array order, so the element with the largest index will be drawn on top.
It can be defined in an XML file with the <layer-list>
element.
Each Drawable in the layer is defined in a nested <item>
.
XML Attributes | |||||||||||
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android:bottom | |||||||||||
android:drawable | Reference to a drawable resource to use for the frame. | ||||||||||
android:id | Supply an identifier name for this view, to later retrieve it with View.findViewById() or Activity.findViewById(). | ||||||||||
android:left | |||||||||||
android:right | |||||||||||
android:top |
Public Constructors | |||||||||||
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Create a new layer drawable with the list of specified layers.
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Public Methods | |||||||||||
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Draw in its bounds (set via setBounds) respecting optional effects such
as alpha (set via setAlpha) and color filter (set via setColorFilter).
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Look for a layer with the given id, and returns its Drawable.
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Return a mask of the configuration parameters for which this drawable
mau change, requiring that it be re-created.
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Returns the drawable at the specified layer index.
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Returns the id of the specified layer.
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Return the intrinsic height of the underlying drawable object.
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Return the intrinsic width of the underlying drawable object.
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Returns the number of layers contained within this.
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Return the opacity/transparency of this Drawable.
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Return in padding the insets suggested by this Drawable for placing
content inside the drawable's bounds.
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Called when the drawable needs to be redrawn.
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Indicates whether this view will change its appearance based on state.
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Make this drawable mutable.
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A Drawable can call this to schedule the next frame of its
animation.
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Specify an alpha value for the drawable.
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Specify an optional colorFilter for the drawable.
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Set to true to have the drawable dither its colors when drawn to a device
with fewer than 8-bits per color component.
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Sets (or replaces) the Drawable for the layer with the given id.
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Sets the ID of a layer.
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Specify modifiers to the bounds for the drawable[index].
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Set whether this Drawable is visible.
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A Drawable can call this to unschedule an action previously
scheduled with scheduleDrawable(Drawable, Runnable, long).
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Protected Methods | |||||||||||
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Override this in your subclass to change appearance if you recognize the
specified state.
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Override this in your subclass to change appearance if you vary based
on level.
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Override this in your subclass to change appearance if you recognize the
specified state.
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[Expand]
Inherited Methods | |||||||||||
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From class android.graphics.drawable.Drawable
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From class java.lang.Object
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From interface android.graphics.drawable.Drawable.Callback
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Reference to a drawable resource to use for the frame. If not given, the drawable must be defined by the first child tag.
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 drawable.
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.
Create a new layer drawable with the list of specified layers.
layers | A list of drawables to use as layers in this new drawable. |
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Draw in its bounds (set via setBounds) respecting optional effects such as alpha (set via setAlpha) and color filter (set via setColorFilter).
canvas | The canvas to draw into |
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Return a mask of the configuration parameters for which this drawable mau change, requiring that it be re-created. The default implementation returns whatever was provided through setChangingConfigurations(int) or 0 by default. Subclasses may extend this to or in the changing configurations of any other drawables they hold.
Returns the drawable at the specified layer index.
index | The layer index of the drawable to retrieve. |
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Returns the id of the specified layer.
index | The index of the layer. |
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Return the intrinsic height of the underlying drawable object. Returns -1 if it has no intrinsic height, such as with a solid color.
Return the intrinsic width of the underlying drawable object. Returns -1 if it has no intrinsic width, such as with a solid color.
Returns the number of layers contained within this.
Return the opacity/transparency of this Drawable. The returned value is one of the abstract format constants in PixelFormat: UNKNOWN, TRANSLUCENT, TRANSPARENT, or OPAQUE.
Generally a Drawable should be as conservative as possible with the value it returns. For example, if it contains multiple child drawables and only shows one of them at a time, if only one of the children is TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be returned. You can use the method resolveOpacity(int, int) to perform a standard reduction of two opacities to the appropriate single output.
Note that the returned value does not take into account a custom alpha or color filter that has been applied by the client through the setAlpha(int) or setColorFilter(ColorFilter) methods.
Return in padding the insets suggested by this Drawable for placing content inside the drawable's bounds. Positive values move toward the center of the Drawable (set Rect.inset). Returns true if this drawable actually has a padding, else false. When false is returned, the padding is always set to 0.
Called when the drawable needs to be redrawn. A view at this point should invalidate itself (or at least the part of itself where the drawable appears).
who | The drawable that is requesting the update. |
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Indicates whether this view will change its appearance based on state. Clients can use this to determine whether it is necessary to calculate their state and call setState.
Make this drawable mutable. This operation cannot be reversed. A mutable drawable is guaranteed to not share its state with any other drawable. This is especially useful when you need to modify properties of drawables loaded from resources. By default, all drawables instances loaded from the same resource share a common state; if you modify the state of one instance, all the other instances will receive the same modification. Calling this method on a mutable Drawable will have no effect.
A Drawable can call this to schedule the next frame of its animation. An implementation can generally simply call postAtTime(Runnable, Object, long) with the parameters (what, who, when) to perform the scheduling.
who | The drawable being scheduled. |
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what | The action to execute. |
when | The time (in milliseconds) to run. The timebase is uptimeMillis() |
Specify an alpha value for the drawable. 0 means fully transparent, and 255 means fully opaque.
Specify an optional colorFilter for the drawable. Pass null to remove any filters.
Set to true to have the drawable dither its colors when drawn to a device with fewer than 8-bits per color component. This can improve the look on those devices, but can also slow down the drawing a little.
Sets the ID of a layer.
index | The index of the layer which will received the ID. |
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id | The ID to assign to the layer. |
Specify modifiers to the bounds for the drawable[index]. left += l top += t; right -= r; bottom -= b;
Set whether this Drawable is visible. This generally does not impact the Drawable's behavior, but is a hint that can be used by some Drawables, for example, to decide whether run animations.
visible | Set to true if visible, false if not. |
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restart | You can supply true here to force the drawable to behave as if it has just become visible, even if it had last been set visible. Used for example to force animations to restart. |
A Drawable can call this to unschedule an action previously scheduled with scheduleDrawable(Drawable, Runnable, long). An implementation can generally simply call removeCallbacks(Runnable, Object) with the parameters (what, who) to unschedule the drawable.
who | The drawable being unscheduled. |
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what | The action being unscheduled. |
Override this in your subclass to change appearance if you recognize the specified state.
Override this in your subclass to change appearance if you vary based on level.
Override this in your subclass to change appearance if you recognize the specified state.