LoaderManagerpublic abstract class LoaderManager extends Object | Interface associated with an {@link Activity} or {@link Fragment} for managing
one or more {@link android.content.Loader} instances associated with it. This
helps an application manage longer-running operations in conjunction with the
Activity or Fragment lifecycle; the most common use of this is with a
{@link android.content.CursorLoader}, however applications are free to write
their own loaders for loading other types of data.
While the LoaderManager API was introduced in
{@link android.os.Build.VERSION_CODES#HONEYCOMB}, a version of the API
at is also available for use on older platforms through
{@link android.support.v4.app.FragmentActivity}. See the blog post
Fragments For All for more details.
As an example, here is the full implementation of a {@link Fragment}
that displays a {@link android.widget.ListView} containing the results of
a query against the contacts content provider. It uses a
{@link android.content.CursorLoader} to manage the query on the provider.
{@sample development/samples/ApiDemos/src/com/example/android/apis/app/LoaderCursor.java
fragment_cursor}
Developer Guides
For more information about using loaders, read the
Loaders developer guide.
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| Methods Summary |
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| 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
{@link LoaderCallbacks#onLoadFinished(Loader, Object)}, a call
will be made to {@link LoaderCallbacks#onLoaderReset(Loader)}.
| | public abstract void | dump(java.lang.String prefix, java.io.FileDescriptor fd, java.io.PrintWriter writer, java.lang.String[] args)Print the LoaderManager's state into the given stream.
| | 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.
LoaderManagerImpl.DEBUG = enabled;
| | public abstract android.content.Loader | getLoader(int id)Return the Loader with the given id or null if no matching Loader
is found.
| | public abstract android.content.Loader | initLoader(int id, android.os.Bundle args, android.app.LoaderManager$LoaderCallbacks callback)Ensures a loader is initialized and active. If the loader doesn't
already exist, one is created and (if the activity/fragment is currently
started) starts the loader. Otherwise the last created
loader is re-used.
In either case, the given callback is associated with the loader, and
will be called as the loader state changes. If at the point of call
the caller is in its started state, and the requested loader
already exists and has generated its data, then
callback {@link LoaderCallbacks#onLoadFinished} will
be called immediately (inside of this function), so you must be prepared
for this to happen.
| | public abstract android.content.Loader | restartLoader(int id, android.os.Bundle args, android.app.LoaderManager$LoaderCallbacks callback)Starts a new or restarts an existing {@link android.content.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.
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