to top
Android APIs
public abstract class

LoaderManager

extends Object
java.lang.Object
   ↳ android.support.v4.app.LoaderManager

Class Overview

Static library support version of the framework's LoaderManager. Used to write apps that run on platforms prior to Android 3.0. When running on Android 3.0 or above, this implementation is still used; it does not try to switch to the framework's implementation. See the framework SDK documentation for a class overview.

Your activity must derive from FragmentActivity to use this.

Summary

Nested Classes
interface LoaderManager.LoaderCallbacks<D> Callback interface for a client to interact with the manager. 
Public Constructors

? Examples 		LoaderManager()
Public Methods

? Examples 		abstract void destroyLoader(int id)
Stops and removes the loader with the given ID.

? Examples 		abstract void dump( String prefix, FileDescriptor fd, PrintWriter writer, String[] args)
Print the LoaderManager's state into the given stream.

? Examples 		static void enableDebugLogging(boolean enabled)
Control whether the framework's internal loader manager debugging logs are turned on.

? Examples 		abstract <D> Loader<D> getLoader(int id)
Return the Loader with the given id or null if no matching Loader is found.

? Examples 		boolean hasRunningLoaders()
Returns true if any loaders managed are currently running and have not returned data to the application yet.

? Examples 		abstract <D> Loader<D> initLoader(int id, Bundle args, LoaderCallbacks<D> callback)
Ensures a loader is initialized and active.

? Examples 		abstract <D> Loader<D> restartLoader(int id, Bundle args, LoaderCallbacks<D> callback)
Starts a new or restarts an existing Loader in this manager, registers the callbacks to it, and (if the activity/fragment is currently started) starts loading it.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public LoaderManager ()

Public Methods

public abstract void destroyLoader (int id)

Stops and removes the loader with the given ID. If this loader had previously reported data to the client through onLoadFinished(Loader, Object), a call will be made to onLoaderReset(Loader).

public abstract void dump (String prefix, FileDescriptor fd, PrintWriter writer, String[] args)

Print the LoaderManager's state into the given stream.

Parameters
prefix Text to print at the front of each line.
fd The raw file descriptor that the dump is being sent to.
writer A PrintWriter to which the dump is to be set.
args Additional arguments to the dump request.

public static void enableDebugLogging (boolean enabled)

Control whether the framework's internal loader manager debugging logs are turned on. If enabled, you will see output in logcat as the framework performs loader operations.

public abstract Loader<D> getLoader (int id)

Return the Loader with the given id or null if no matching Loader is found.

public boolean hasRunningLoaders ()

Returns true if any loaders managed are currently running and have not returned data to the application yet.

public abstract Loader<D> initLoader (int id, Bundle args, LoaderCallbacks<D> callback)

Ensures a loader is initialized and active. If the loader doesn't already exist, one is created and (if the activity/fragment is currently started) starts the loader. Otherwise the last created loader is re-used.

In either case, the given callback is associated with the loader, and will be called as the loader state changes. If at the point of call the caller is in its started state, and the requested loader already exists and has generated its data, then callback onLoadFinished(Loader , D) will be called immediately (inside of this function), so you must be prepared for this to happen.

Parameters
id A unique identifier for this loader. Can be whatever you want. Identifiers are scoped to a particular LoaderManager instance.
args Optional arguments to supply to the loader at construction. If a loader already exists (a new one does not need to be created), this parameter will be ignored and the last arguments continue to be used.
callback Interface the LoaderManager will call to report about changes in the state of the loader. Required.

public abstract Loader<D> restartLoader (int id, Bundle args, LoaderCallbacks<D> callback)

Starts a new or restarts an existing Loader in this manager, registers the callbacks to it, and (if the activity/fragment is currently started) starts loading it. If a loader with the same id has previously been started it will automatically be destroyed when the new loader completes its work. The callback will be delivered before the old loader is destroyed.

Parameters
id A unique identifier for this loader. Can be whatever you want. Identifiers are scoped to a particular LoaderManager instance.
args Optional arguments to supply to the loader at construction.
callback Interface the LoaderManager will call to report about changes in the state of the loader. Required.
No examples for this method.
Frequently called with: [Clear]
Portions of this page are reproduced from work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License. The original page is available here.