ContextWrapper

Connect to an application service, creating it if needed. This defines a dependency between your application and the service. The given conn will receive the service object when its created and be told if it dies and restarts. The service will be considered required by the system only for as long as the calling context exists. For example, if this Context is an Activity that is stopped, the service will not be required to continue running until the Activity is resumed.

This function will throw SecurityException if you do not have permission to bind to the given service.

Note: this method can not be called from an BroadcastReceiver component. A pattern you can use to communicate from an BroadcastReceiver to a Service is to call startService(Intent) with the arguments containing the command to be sent, with the service calling its stopSelf(int) method when done executing that command. See the API demo App/Service/Service Start Arguments Controller for an illustration of this. It is okay, however, to use this method from an BroadcastReceiver that has been registered with registerReceiver(BroadcastReceiver, IntentFilter), since the lifetime of this BroadcastReceiver is tied to another object (the one that registered it).

Determine whether the calling process of an IPC or you have been granted a particular permission. This is the same as checkCallingPermission(String), except it grants your own permissions if you are not currently processing an IPC. Use with care!

Determine whether the calling process of an IPC or you has been granted permission to access a specific URI. This is the same as checkCallingUriPermission(Uri, int), except it grants your own permissions if you are not currently processing an IPC. Use with care!

Determine whether the calling process of an IPC you are handling has been granted a particular permission. This is basically the same as calling checkPermission(String, int, int) with the pid and uid returned by getCallingPid() and getCallingUid(). One important difference is that if you are not currently processing an IPC, this function will always fail. This is done to protect against accidentally leaking permissions; you can use checkCallingOrSelfPermission(String) to avoid this protection.

Determine whether the calling process and user ID has been granted permission to access a specific URI. This is basically the same as calling checkUriPermission(Uri, int, int, int) with the pid and uid returned by getCallingPid() and getCallingUid(). One important difference is that if you are not currently processing an IPC, this function will always fail.

Determine whether the given permission is allowed for a particular process and user ID running in the system.

Determine whether a particular process and user ID has been granted permission to access a specific URI. This only checks for permissions that have been explicitly granted -- if the given process/uid has more general access to the URI's content provider then this check will always fail.

Check both a Uri and normal permission. This allows you to perform both checkPermission(String, int, int) and checkUriPermission(Uri, int, int, int) in one call.

Return a new Context object for the given application name. This Context is the same as what the named application gets when it is launched, containing the same resources and class loader. Each call to this method returns a new instance of a Context object; Context objects are not shared, however they share common state (Resources, ClassLoader, etc) so the Context instance itself is fairly lightweight.

Throws PackageManager.NameNotFoundException if there is no application with the given package name.

Throws SecurityException if the Context requested can not be loaded into the caller's process for security reasons (see CONTEXT_INCLUDE_CODE for more information}.

Returns an array of strings naming the private databases associated with this Context's application package.

Delete an existing private SQLiteDatabase associated with this Context's application package.

Delete the given private file associated with this Context's application package.

If neither you nor the calling process of an IPC you are handling has been granted a particular permission, throw a SecurityException. This is the same as enforceCallingPermission(String, String), except it grants your own permissions if you are not currently processing an IPC. Use with care!

If the calling process of an IPC or you has not been granted permission to access a specific URI, throw SecurityException. This is the same as enforceCallingUriPermission(Uri, int, String), except it grants your own permissions if you are not currently processing an IPC. Use with care!

If the calling process of an IPC you are handling has not been granted a particular permission, throw a SecurityException. This is basically the same as calling enforcePermission(String, int, int, String) with the pid and uid returned by getCallingPid() and getCallingUid(). One important difference is that if you are not currently processing an IPC, this function will always throw the SecurityException. This is done to protect against accidentally leaking permissions; you can use enforceCallingOrSelfPermission(String, String) to avoid this protection.

If the calling process and user ID has not been granted permission to access a specific URI, throw SecurityException. This is basically the same as calling enforceUriPermission(Uri, int, int, int, String) with the pid and uid returned by getCallingPid() and getCallingUid(). One important difference is that if you are not currently processing an IPC, this function will always throw a SecurityException.

If the given permission is not allowed for a particular process and user ID running in the system, throw a SecurityException.

If a particular process and user ID has not been granted permission to access a specific URI, throw SecurityException. This only checks for permissions that have been explicitly granted -- if the given process/uid has more general access to the URI's content provider then this check will always fail.

Enforce both a Uri and normal permission. This allows you to perform both enforcePermission(String, int, int, String) and enforceUriPermission(Uri, int, int, int, String) in one call.

Returns an array of strings naming the private files associated with this Context's application package.

Return the context of the single, global Application object of the current process. This generally should only be used if you need a Context whose lifecycle is separate from the current context, that is tied to the lifetime of the process rather than the current component.

Consider for example how this interacts with registerReceiver(BroadcastReceiver, IntentFilter):

• If used from an Activity context, the receiver is being registered within that activity. This means that you are expected to unregister before the activity is done being destroyed; in fact if you do not do so, the framework will clean up your leaked registration as it removes the activity and log an error. Thus, if you use the Activity context to register a receiver that is static (global to the process, not associated with an Activity instance) then that registration will be removed on you at whatever point the activity you used is destroyed.

• If used from the Context returned here, the receiver is being registered with the global state associated with your application. Thus it will never be unregistered for you. This is necessary if the receiver is associated with static data, not a particular component. However using the ApplicationContext elsewhere can easily lead to serious leaks if you forget to unregister, unbind, etc.

Return the full application info for this context's package.

Return an AssetManager instance for your application's package.

Returns the absolute path to the application specific cache directory on the filesystem. These files will be ones that get deleted first when the device runs low on storage. There is no guarantee when these files will be deleted. Note: you should not rely on the system deleting these files for you; you should always have a reasonable maximum, such as 1 MB, for the amount of space you consume with cache files, and prune those files when exceeding that space.

Return a class loader you can use to retrieve classes in this package.

Return a ContentResolver instance for your application's package.

Returns the absolute path on the filesystem where a database created with openOrCreateDatabase(String, int, SQLiteDatabase.CursorFactory) is stored.

Retrieve, creating if needed, a new directory in which the application can place its own custom data files. You can use the returned File object to create and access files in this directory. Note that files created through a File object will only be accessible by your own application; you can only set the mode of the entire directory, not of individual files.

Returns the absolute path to the directory on the external filesystem (that is somewhere on Environment.getExternalStorageDirectory() where the application can place cache files it owns.

This is like getCacheDir() in that these files will be deleted when the application is uninstalled, however there are some important differences:

• The platform does not monitor the space available in external storage, and thus will not automatically delete these files. Note that you should be managing the maximum space you will use for these anyway, just like with getCacheDir().
• External files are not always available: they will disappear if the user mounts the external storage on a computer or removes it. See the APIs on Environment for information in the storage state.
• There is no security enforced with these files. All applications can read and write files placed here.

Returns the absolute path to the directory on the external filesystem (that is somewhere on Environment.getExternalStorageDirectory()) where the application can place persistent files it owns. These files are private to the applications, and not typically visible to the user as media.

This is like getFilesDir() in that these files will be deleted when the application is uninstalled, however there are some important differences:

• External files are not always available: they will disappear if the user mounts the external storage on a computer or removes it. See the APIs on Environment for information in the storage state.
• There is no security enforced with these files. All applications can read and write files placed here.

Here is an example of typical code to manipulate a file in an application's private storage:

void createExternalStoragePrivateFile() {
    // Create a path where we will place our private file on external
    // storage.
    File file = new File(getExternalFilesDir(null), "DemoFile.jpg");

    try {
        // Very simple code to copy a picture from the application's
        // resource into the external file.  Note that this code does
        // no error checking, and assumes the picture is small (does not
        // try to copy it in chunks).  Note that if external storage is
        // not currently mounted this will silently fail.
        InputStream is = getResources().openRawResource(R.drawable.balloons);
        OutputStream os = new FileOutputStream(file);
        byte[] data = new byte[is.available()];
        is.read(data);
        os.write(data);
        is.close();
        os.close();
    } catch (IOException e) {
        // Unable to create file, likely because external storage is
        // not currently mounted.
        Log.w("ExternalStorage", "Error writing " + file, e);
    }
}

void deleteExternalStoragePrivateFile() {
    // Get path for the file on external storage.  If external
    // storage is not currently mounted this will fail.
    File file = new File(getExternalFilesDir(null), "DemoFile.jpg");
    if (file != null) {
        file.delete();
    }
}

boolean hasExternalStoragePrivateFile() {
    // Get path for the file on external storage.  If external
    // storage is not currently mounted this will fail.
    File file = new File(getExternalFilesDir(null), "DemoFile.jpg");
    if (file != null) {
        return file.exists();
    }
    return false;
}

If you supply a non-null type to this function, the returned file will be a path to a sub-directory of the given type. Though these files are not automatically scanned by the media scanner, you can explicitly add them to the media database with MediaScannerConnection.scanFile. Note that this is not the same as Environment.getExternalStoragePublicDirectory(), which provides directories of media shared by all applications. The directories returned here are owned by the application, and their contents will be removed when the application is uninstalled. Unlike Environment.getExternalStoragePublicDirectory(), the directory returned here will be automatically created for you.

Here is an example of typical code to manipulate a picture in an application's private storage and add it to the media database:

void createExternalStoragePrivatePicture() {
    // Create a path where we will place our picture in our own private
    // pictures directory.  Note that we don't really need to place a
    // picture in DIRECTORY_PICTURES, since the media scanner will see
    // all media in these directories; this may be useful with other
    // media types such as DIRECTORY_MUSIC however to help it classify
    // your media for display to the user.
    File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    File file = new File(path, "DemoPicture.jpg");

    try {
        // Very simple code to copy a picture from the application's
        // resource into the external file.  Note that this code does
        // no error checking, and assumes the picture is small (does not
        // try to copy it in chunks).  Note that if external storage is
        // not currently mounted this will silently fail.
        InputStream is = getResources().openRawResource(R.drawable.balloons);
        OutputStream os = new FileOutputStream(file);
        byte[] data = new byte[is.available()];
        is.read(data);
        os.write(data);
        is.close();
        os.close();

        // Tell the media scanner about the new file so that it is
        // immediately available to the user.
        MediaScannerConnection.scanFile(this,
                new String[] { file.toString() }, null,
                new MediaScannerConnection.OnScanCompletedListener() {
            public void onScanCompleted(String path, Uri uri) {
                Log.i("ExternalStorage", "Scanned " + path + ":");
                Log.i("ExternalStorage", "-> uri=" + uri);
            }
        });
    } catch (IOException e) {
        // Unable to create file, likely because external storage is
        // not currently mounted.
        Log.w("ExternalStorage", "Error writing " + file, e);
    }
}

void deleteExternalStoragePrivatePicture() {
    // Create a path where we will place our picture in the user's
    // public pictures directory and delete the file.  If external
    // storage is not currently mounted this will fail.
    File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    if (path != null) {
        File file = new File(path, "DemoPicture.jpg");
        file.delete();
    }
}

boolean hasExternalStoragePrivatePicture() {
    // Create a path where we will place our picture in the user's
    // public pictures directory and check if the file exists.  If
    // external storage is not currently mounted this will think the
    // picture doesn't exist.
    File path = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    if (path != null) {
        File file = new File(path, "DemoPicture.jpg");
        return file.exists();
    }
    return false;
}

Returns the absolute path on the filesystem where a file created with openFileOutput(String, int) is stored.

Returns the absolute path to the directory on the filesystem where files created with openFileOutput(String, int) are stored.

Return the Looper for the main thread of the current process. This is the thread used to dispatch calls to application components (activities, services, etc).

Return the directory where this application's OBB files (if there are any) can be found. Note if the application does not have any OBB files, this directory may not exist.

Return the full path to this context's primary Android package. The Android package is a ZIP file which contains application's primary code and assets.

Note: this is not generally useful for applications, since they should not be directly accessing the file system.

Return PackageManager instance to find global package information.

Return the name of this application's package.

Return the full path to this context's primary Android package. The Android package is a ZIP file which contains the application's primary resources.

Note: this is not generally useful for applications, since they should not be directly accessing the file system.

Return a Resources instance for your application's package.

Retrieve and hold the contents of the preferences file 'name', returning a SharedPreferences through which you can retrieve and modify its values. Only one instance of the SharedPreferences object is returned to any callers for the same name, meaning they will see each other's edits as soon as they are made.

Return the handle to a system-level service by name. The class of the returned object varies by the requested name. Currently available names are:

WINDOW_SERVICE ("window")

The top-level window manager in which you can place custom windows. The returned object is a WindowManager.

LAYOUT_INFLATER_SERVICE ("layout_inflater")

A LayoutInflater for inflating layout resources in this context.

ACTIVITY_SERVICE ("activity")

A ActivityManager for interacting with the global activity state of the system.

POWER_SERVICE ("power")

A PowerManager for controlling power management.

ALARM_SERVICE ("alarm")

A AlarmManager for receiving intents at the time of your choosing.

NOTIFICATION_SERVICE ("notification")

A NotificationManager for informing the user of background events.

KEYGUARD_SERVICE ("keyguard")

A KeyguardManager for controlling keyguard.

LOCATION_SERVICE ("location")

A LocationManager for controlling location (e.g., GPS) updates.

SEARCH_SERVICE ("search")

A SearchManager for handling search.

VIBRATOR_SERVICE ("vibrator")

A Vibrator for interacting with the vibrator hardware.

CONNECTIVITY_SERVICE ("connection")

A ConnectivityManager for handling management of network connections.

WIFI_SERVICE ("wifi")

A WifiManager for management of Wi-Fi connectivity.

INPUT_METHOD_SERVICE ("input_method")

An InputMethodManager for management of input methods.

UI_MODE_SERVICE ("uimode")

An UiModeManager for controlling UI modes.

DOWNLOAD_SERVICE ("download")

A DownloadManager for requesting HTTP downloads

Note: System services obtained via this API may be closely associated with the Context in which they are obtained from. In general, do not share the service objects between various different contexts (Activities, Applications, Services, Providers, etc.)

Return the Theme object associated with this Context.

Grant permission to access a specific Uri to another package, regardless of whether that package has general permission to access the Uri's content provider. This can be used to grant specific, temporary permissions, typically in response to user interaction (such as the user opening an attachment that you would like someone else to display).

Normally you should use Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION with the Intent being used to start an activity instead of this function directly. If you use this function directly, you should be sure to call revokeUriPermission(Uri, int) when the target should no longer be allowed to access it.

To succeed, the content provider owning the Uri must have set the grantUriPermissions attribute in its manifest or included the <grant-uri-permissions> tag.

Indicates whether this Context is restricted.

Open a private file associated with this Context's application package for reading.

Open a private file associated with this Context's application package for writing. Creates the file if it doesn't already exist.

Open a new private SQLiteDatabase associated with this Context's application package. Create the database file if it doesn't exist.

Open a new private SQLiteDatabase associated with this Context's application package. Creates the database file if it doesn't exist.

Accepts input param: a concrete instance of DatabaseErrorHandler to be used to handle corruption when sqlite reports database corruption.

Register a BroadcastReceiver to be run in the main activity thread. The receiver will be called with any broadcast Intent that matches filter, in the main application thread.

The system may broadcast Intents that are "sticky" -- these stay around after the broadcast as finished, to be sent to any later registrations. If your IntentFilter matches one of these sticky Intents, that Intent will be returned by this function and sent to your receiver as if it had just been broadcast.

There may be multiple sticky Intents that match filter, in which case each of these will be sent to receiver. In this case, only one of these can be returned directly by the function; which of these that is returned is arbitrarily decided by the system.

If you know the Intent your are registering for is sticky, you can supply null for your receiver. In this case, no receiver is registered -- the function simply returns the sticky Intent that matches filter. In the case of multiple matches, the same rules as described above apply.

See BroadcastReceiver for more information on Intent broadcasts.

Note: this method cannot be called from a BroadcastReceiver component; that is, from a BroadcastReceiver that is declared in an application's manifest. It is okay, however, to call this method from another BroadcastReceiver that has itself been registered at run time with registerReceiver(BroadcastReceiver, IntentFilter), since the lifetime of such a registered BroadcastReceiver is tied to the object that registered it.

Register to receive intent broadcasts, to run in the context of scheduler. See registerReceiver(BroadcastReceiver, IntentFilter) for more information. This allows you to enforce permissions on who can broadcast intents to your receiver, or have the receiver run in a different thread than the main application thread.

See BroadcastReceiver for more information on Intent broadcasts.

Remove the data previously sent with sendStickyBroadcast(Intent), so that it is as if the sticky broadcast had never happened.

You must hold the BROADCAST_STICKY permission in order to use this API. If you do not hold that permission, SecurityException will be thrown.

Remove all permissions to access a particular content provider Uri that were previously added with grantUriPermission(String, Uri, int). The given Uri will match all previously granted Uris that are the same or a sub-path of the given Uri. That is, revoking "content://foo/one" will revoke both "content://foo/target" and "content://foo/target/sub", but not "content://foo".

Broadcast the given intent to all interested BroadcastReceivers. This call is asynchronous; it returns immediately, and you will continue executing while the receivers are run. No results are propagated from receivers and receivers can not abort the broadcast. If you want to allow receivers to propagate results or abort the broadcast, you must send an ordered broadcast using sendOrderedBroadcast(Intent, String).

See BroadcastReceiver for more information on Intent broadcasts.

Broadcast the given intent to all interested BroadcastReceivers, allowing an optional required permission to be enforced. This call is asynchronous; it returns immediately, and you will continue executing while the receivers are run. No results are propagated from receivers and receivers can not abort the broadcast. If you want to allow receivers to propagate results or abort the broadcast, you must send an ordered broadcast using sendOrderedBroadcast(Intent, String).

See BroadcastReceiver for more information on Intent broadcasts.

Version of sendBroadcast(Intent) that allows you to receive data back from the broadcast. This is accomplished by supplying your own BroadcastReceiver when calling, which will be treated as a final receiver at the end of the broadcast -- its onReceive(Context, Intent) method will be called with the result values collected from the other receivers. The broadcast will be serialized in the same way as calling sendOrderedBroadcast(Intent, String).

Like sendBroadcast(Intent), this method is asynchronous; it will return before resultReceiver.onReceive() is called.

See BroadcastReceiver for more information on Intent broadcasts.

Broadcast the given intent to all interested BroadcastReceivers, delivering them one at a time to allow more preferred receivers to consume the broadcast before it is delivered to less preferred receivers. This call is asynchronous; it returns immediately, and you will continue executing while the receivers are run.

See BroadcastReceiver for more information on Intent broadcasts.

Perform a sendBroadcast(Intent) that is "sticky," meaning the Intent you are sending stays around after the broadcast is complete, so that others can quickly retrieve that data through the return value of registerReceiver(BroadcastReceiver, IntentFilter). In all other ways, this behaves the same as sendBroadcast(Intent).

You must hold the BROADCAST_STICKY permission in order to use this API. If you do not hold that permission, SecurityException will be thrown.

Version of sendStickyBroadcast(Intent) that allows you to receive data back from the broadcast. This is accomplished by supplying your own BroadcastReceiver when calling, which will be treated as a final receiver at the end of the broadcast -- its onReceive(Context, Intent) method will be called with the result values collected from the other receivers. The broadcast will be serialized in the same way as calling sendOrderedBroadcast(Intent, String).

Like sendBroadcast(Intent), this method is asynchronous; it will return before resultReceiver.onReceive() is called. Note that the sticky data stored is only the data you initially supply to the broadcast, not the result of any changes made by the receivers.

See BroadcastReceiver for more information on Intent broadcasts.

Set the base theme for this context. Note that this should be called before any views are instantiated in the Context (for example before calling setContentView(View) or inflate(int, ViewGroup)).

Launch multiple new activities. This is generally the same as calling startActivity(Intent) for the first Intent in the array, that activity during its creation calling startActivity(Intent) for the second entry, etc. Note that unlike that approach, generally none of the activities except the last in the array will be created at this point, but rather will be created when the user first visits them (due to pressing back from the activity on top).

This method throws ActivityNotFoundException if there was no Activity found for any given Intent. In this case the state of the activity stack is undefined (some Intents in the list may be on it, some not), so you probably want to avoid such situations.

Launch a new activity. You will not receive any information about when the activity exits.

Note that if this method is being called from outside of an Activity Context, then the Intent must include the FLAG_ACTIVITY_NEW_TASK launch flag. This is because, without being started from an existing Activity, there is no existing task in which to place the new activity and thus it needs to be placed in its own separate task.

This method throws ActivityNotFoundException if there was no Activity found to run the given Intent.

Start executing an Instrumentation class. The given Instrumentation component will be run by killing its target application (if currently running), starting the target process, instantiating the instrumentation component, and then letting it drive the application.

This function is not synchronous -- it returns as soon as the instrumentation has started and while it is running.

Instrumentation is normally only allowed to run against a package that is either unsigned or signed with a signature that the the instrumentation package is also signed with (ensuring the target trusts the instrumentation).

Like startActivity(Intent), but taking a IntentSender to start. If the IntentSender is for an activity, that activity will be started as if you had called the regular startActivity(Intent) here; otherwise, its associated action will be executed (such as sending a broadcast) as if you had called IntentSender.sendIntent on it.

Request that a given application service be started. The Intent can either contain the complete class name of a specific service implementation to start, or an abstract definition through the action and other fields of the kind of service to start. If this service is not already running, it will be instantiated and started (creating a process for it if needed); if it is running then it remains running.

Every call to this method will result in a corresponding call to the target service's onStartCommand(Intent, int, int) method, with the intent given here. This provides a convenient way to submit jobs to a service without having to bind and call on to its interface.

Using startService() overrides the default service lifetime that is managed by bindService(Intent, ServiceConnection, int): it requires the service to remain running until stopService(Intent) is called, regardless of whether any clients are connected to it. Note that calls to startService() are not nesting: no matter how many times you call startService(), a single call to stopService(Intent) will stop it.

The system attempts to keep running services around as much as possible. The only time they should be stopped is if the current foreground application is using so many resources that the service needs to be killed. If any errors happen in the service's process, it will automatically be restarted.

This function will throw SecurityException if you do not have permission to start the given service.

Request that a given application service be stopped. If the service is not running, nothing happens. Otherwise it is stopped. Note that calls to startService() are not counted -- this stops the service no matter how many times it was started.

Note that if a stopped service still has ServiceConnection objects bound to it with the BIND_AUTO_CREATE set, it will not be destroyed until all of these bindings are removed. See the Service documentation for more details on a service's lifecycle.

This function will throw SecurityException if you do not have permission to stop the given service.

Disconnect from an application service. You will no longer receive calls as the service is restarted, and the service is now allowed to stop at any time.

Unregister a previously registered BroadcastReceiver. All filters that have been registered for this BroadcastReceiver will be removed.

Set the base context for this ContextWrapper. All calls will then be delegated to the base context. Throws IllegalStateException if a base context has already been set.