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AsyncTaskLoader

public abstract class AsyncTaskLoader
extends Loader<D>

java.lang.Object
   ↳ android.support.v4.content.Loader<D>
     ↳ android.support.v4.content.AsyncTaskLoader<D>
Known Direct Subclasses


Static library support version of the framework's AsyncTaskLoader. 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.

Summary

Public constructors

AsyncTaskLoader(Context context)

Public methods

void cancelLoadInBackground()

Called on the main thread to abort a load in progress.

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

Print the Loader's state into the given stream.

boolean isLoadInBackgroundCanceled()

Returns true if the current invocation of loadInBackground() is being canceled.

abstract D loadInBackground()

Called on a worker thread to perform the actual load and to return the result of the load operation.

void onCanceled(D data)

Called if the task was canceled before it was completed.

void setUpdateThrottle(long delayMS)

Set amount to throttle updates by.

Protected methods

boolean onCancelLoad()

Subclasses must implement this to take care of requests to cancelLoad().

void onForceLoad()

Subclasses must implement this to take care of requests to forceLoad().

D onLoadInBackground()

Calls loadInBackground().

Inherited methods

From class android.support.v4.content.Loader
From class java.lang.Object

Public constructors

AsyncTaskLoader

AsyncTaskLoader (Context context)

Parameters
context Context

Public methods

cancelLoadInBackground

void cancelLoadInBackground ()

Called on the main thread to abort a load in progress. Override this method to abort the current invocation of loadInBackground() that is running in the background on a worker thread. This method should do nothing if loadInBackground() has not started running or if it has already finished.

See also:

dump

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

Print the Loader's state into the given stream.

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

isLoadInBackgroundCanceled

boolean isLoadInBackgroundCanceled ()

Returns true if the current invocation of loadInBackground() is being canceled.

Returns
boolean True if the current invocation of loadInBackground() is being canceled.

See also:

loadInBackground

D loadInBackground ()

Called on a worker thread to perform the actual load and to return the result of the load operation. Implementations should not deliver the result directly, but should return them from this method, which will eventually end up calling deliverResult(D) on the UI thread. If implementations need to process the results on the UI thread they may override deliverResult(D) and do so there. To support cancellation, this method should periodically check the value of isLoadInBackgroundCanceled() and terminate when it returns true. Subclasses may also override cancelLoadInBackground() to interrupt the load directly instead of polling isLoadInBackgroundCanceled(). When the load is canceled, this method may either return normally or throw OperationCanceledException. In either case, the Loader will call onCanceled(D) to perform post-cancellation cleanup and to dispose of the result object, if any.

Returns
D The result of the load operation.
Throws
OperationCanceledException if the load is canceled during execution.

See also:

onCanceled

void onCanceled (D data)

Called if the task was canceled before it was completed. Gives the class a chance to clean up post-cancellation and to properly dispose of the result.

Parameters
data D: The value that was returned by loadInBackground(), or null if the task threw OperationCanceledException.

setUpdateThrottle

void setUpdateThrottle (long delayMS)

Set amount to throttle updates by. This is the minimum time from when the last loadInBackground() call has completed until a new load is scheduled.

Parameters
delayMS long: Amount of delay, in milliseconds.

Protected methods

onCancelLoad

boolean onCancelLoad ()

Subclasses must implement this to take care of requests to cancelLoad(). This will always be called from the process's main thread.

Returns
boolean Returns false if the task could not be canceled, typically because it has already completed normally, or because startLoading() hasn't been called; returns true otherwise. When true is returned, the task is still running and the Loader.OnLoadCanceledListener will be called when the task completes.

onForceLoad

void onForceLoad ()

Subclasses must implement this to take care of requests to forceLoad(). This will always be called from the process's main thread.

onLoadInBackground

D onLoadInBackground ()

Calls loadInBackground(). This method is reserved for use by the loader framework. Subclasses should override loadInBackground() instead of this method.

Returns
D The result of the load operation.
Throws
OperationCanceledException if the load is canceled during execution.

See also:

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