Known Direct Subclasses
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Represents a pending result from calling an API method in Google Play services. The final result
object from a PendingResult After the result has been retrieved using
await()
, or await(long, TimeUnit)
, or
ResultCallback
to
setResultCallback(ResultCallback super R>)
.
await()
or delivered to the result callback,
it is an error to attempt to retrieve the result again. It is the responsibility of the caller or
callback receiver to release any resources associated with the returned result. Some result types
may implement Releasable
, in which case release()
should be used to free
the associated resources.
Public Constructor Summary
Public Method Summary
abstract R |
await()
Blocks until the task is completed.
|
abstract R | |
abstract void |
cancel()
Requests that the PendingResult be canceled.
|
abstract boolean |
isCanceled()
Indicates whether the pending result has been canceled either due to calling
disconnect() or calling cancel() directly on the pending result or an
enclosing Batch . |
abstract void |
setResultCallback(ResultCallback<? super R> callback)
Set the callback here if you want the result to be delivered via a callback when the result is
ready.
|
abstract void |
setResultCallback(ResultCallback<? super R> callback, long time, TimeUnit units)
Set the callback here if you want the result to be delivered via a callback when the result is
ready or has timed out waiting for the result.
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<S extends Result> TransformedResult<S> |
then(ResultTransform<? super R, ? extends S> transform)
Transforms the result by making another API call.
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Inherited Method Summary
Public Constructors
public PendingResult ()
Public Methods
public abstract R await ()
Blocks until the task is completed. This is not allowed on the UI thread. The returned result
object can have an additional failure mode of INTERRUPTED
.
public abstract R await (long time, TimeUnit units)
Blocks until the task is completed or has timed out waiting for the result. This is not allowed
on the UI thread. The returned result object can have an additional failure mode of either
INTERRUPTED
or TIMEOUT
.
public abstract void cancel ()
Requests that the PendingResult be canceled. If the result is available, but not consumed it will be released. If the result is set after cancelation was requested it is immediately released.
onResult(Result)
will never be called, await()
will return a
failed result with CANCELED
.
public abstract boolean isCanceled ()
Indicates whether the pending result has been canceled either due to calling disconnect()
or calling cancel()
directly on the pending result or an
enclosing Batch
.
public abstract void setResultCallback (ResultCallback<? super R> callback)
Set the callback here if you want the result to be delivered via a callback when the result is ready.
public abstract void setResultCallback (ResultCallback<? super R> callback, long time, TimeUnit units)
Set the callback here if you want the result to be delivered via a callback when the result is
ready or has timed out waiting for the result. The returned result object can have an
additional failure mode of TIMEOUT
.
public TransformedResult<S> then (ResultTransform<? super R, ? extends S> transform)
Transforms the result by making another API call.
If the result is successful, then onSuccess(R)
will be called to make
the additional API call that yields the transformed result. If the result is a failure, then
onFailure(Status)
will be called to (optionally) allow modification of failure
status.
If the result implements Releasable
, then release()
will be called
once the transform has been applied.
Multiple API calls can be chained together by making subsequent calls to then(ResultTransform super R, ? extends S>)
and the final result can be received by an instance of ResultCallbacks
specified via andFinally(ResultCallbacks super R>)
. For example:
final DriveFolder rootFolder = Drive.DriveApi.getRootFolder(mApiClient); Drive.DriveApi.newDriveContents(mApiClient) .then(new ResultTransform<DriveContentsResult, DriveFileResult>() { @Override public PendingResult<DriveFileResult> onSuccess(DriveContentsResult result) { DriveContents driveContents = result.getDriveContents(); // Write content to DriveContents OutputStream outputStream = driveContents.getOutputStream(); PrintWriter writer = new PrintWriter(outputStream); writer.write("Hello World!"); writer.close(); MetadataChangeSet changeSet = new MetadataChangeSet.Builder() .setTitle("hello.txt") .setMimeType("text/plain") .build(); // Create a file on root folder return rootFolder.createFile(mApiClient, changeSet, driveContents); } }) .then(new ResultTransform<DriveFileResult, MetadataBufferResult>() { @Override public PendingResult<MetadataBufferResult> onSuccess(DriveFileResult result) { // Fetch the updated root folder contents return rootFolder.listChildren(mApiClient) } }) .andFinally(new ResultCallbacks<MetadataBufferResult>() { @Override public void onSuccess(MetadataBufferResult result) { // All API calls were successful. } @Override public void onFailure(Status status) { // An API call failed. } });
All ResultTransform
s will be run on a worker thread. These transforms therefore must
not interact with UI elements, but they may perform brief background work (not requiring more
than a few seconds). If ResultCallbacks
are specified, these will be called on the
thread specified by setHandler(Handler)
or on the main thread by
default.
If disconnect()
is called before a series of transforms completes the
transforms will continue to run in the background until the last one completes. In this case,
ResultCallbacks
will not be called. Note that this may cause memory leaks if background
transformations are long-running. For long background tasks, consider using an IntentService
.
Note: it is an error to use multiple GoogleApiClient
s for various API calls within
subsequent ResultTransform
s. Behavior is undefined if calls don't use the same
GoogleApiClient.