(this, result));
- message.sendToTarget();
- return result;
- }
-
- /**
- * Returns the current status of this task.
- *
- * @return The current status.
- */
- public final Status getStatus() {
- return mStatus;
- }
-
- /**
- * Override this method to perform a computation on a background thread. The
- * specified parameters are the parameters passed to {@link #execute}
- * by the caller of this task.
- *
- * This method can call {@link #publishProgress} to publish updates
- * on the UI thread.
- *
- * @param params The parameters of the task.
- *
- * @return A result, defined by the subclass of this task.
- *
- * @see #onPreExecute()
- * @see #onPostExecute
- * @see #publishProgress
- */
- protected abstract Result doInBackground(Params... params);
-
- /**
- * Runs on the UI thread before {@link #doInBackground}.
- *
- * @see #onPostExecute
- * @see #doInBackground
- */
- protected void onPreExecute() {
- }
-
- /**
- * Runs on the UI thread after {@link #doInBackground}. The
- * specified result is the value returned by {@link #doInBackground}.
- *
- * This method won't be invoked if the task was cancelled.
- *
- * @param result The result of the operation computed by {@link #doInBackground}.
- *
- * @see #onPreExecute
- * @see #doInBackground
- * @see #onCancelled(Object)
- */
- @SuppressWarnings({"UnusedDeclaration"})
- protected void onPostExecute(Result result) {
- }
-
- /**
- * Runs on the UI thread after {@link #publishProgress} is invoked.
- * The specified values are the values passed to {@link #publishProgress}.
- *
- * @param values The values indicating progress.
- *
- * @see #publishProgress
- * @see #doInBackground
- */
- @SuppressWarnings({"UnusedDeclaration"})
- protected void onProgressUpdate(Progress... values) {
- }
-
- /**
- * Runs on the UI thread after {@link #cancel(boolean)} is invoked and
- * {@link #doInBackground(Object[])} has finished.
- *
- * The default implementation simply invokes {@link #onCancelled()} and
- * ignores the result. If you write your own implementation, do not call
- * super.onCancelled(result).
- *
- * @param result The result, if any, computed in
- * {@link #doInBackground(Object[])}, can be null
- *
- * @see #cancel(boolean)
- * @see #isCancelled()
- */
- @SuppressWarnings({"UnusedParameters"})
- protected void onCancelled(Result result) {
- onCancelled();
- }
-
- /**
- * Applications should preferably override {@link #onCancelled(Object)}.
- * This method is invoked by the default implementation of
- * {@link #onCancelled(Object)}.
- *
- * Runs on the UI thread after {@link #cancel(boolean)} is invoked and
- * {@link #doInBackground(Object[])} has finished.
- *
- * @see #onCancelled(Object)
- * @see #cancel(boolean)
- * @see #isCancelled()
- */
- protected void onCancelled() {
- }
-
- /**
- * Returns true if this task was cancelled before it completed
- * normally. If you are calling {@link #cancel(boolean)} on the task,
- * the value returned by this method should be checked periodically from
- * {@link #doInBackground(Object[])} to end the task as soon as possible.
- *
- * @return true if task was cancelled before it completed
- *
- * @see #cancel(boolean)
- */
- public final boolean isCancelled() {
- return mCancelled.get();
- }
-
- /**
- * Attempts to cancel execution of this task. This attempt will
- * fail if the task has already completed, already been cancelled,
- * or could not be cancelled for some other reason. If successful,
- * and this task has not started when cancel is called,
- * this task should never run. If the task has already started,
- * then the mayInterruptIfRunning parameter determines
- * whether the thread executing this task should be interrupted in
- * an attempt to stop the task.
- *
- * Calling this method will result in {@link #onCancelled(Object)} being
- * invoked on the UI thread after {@link #doInBackground(Object[])}
- * returns. Calling this method guarantees that {@link #onPostExecute(Object)}
- * is never invoked. After invoking this method, you should check the
- * value returned by {@link #isCancelled()} periodically from
- * {@link #doInBackground(Object[])} to finish the task as early as
- * possible.
- *
- * @param mayInterruptIfRunning true if the thread executing this
- * task should be interrupted; otherwise, in-progress tasks are allowed
- * to complete.
- *
- * @return false if the task could not be cancelled,
- * typically because it has already completed normally;
- * true otherwise
- *
- * @see #isCancelled()
- * @see #onCancelled(Object)
- */
- public final boolean cancel(boolean mayInterruptIfRunning) {
- mCancelled.set(true);
- return mFuture.cancel(mayInterruptIfRunning);
- }
-
- /**
- * Waits if necessary for the computation to complete, and then
- * retrieves its result.
- *
- * @return The computed result.
- *
- * @throws CancellationException If the computation was cancelled.
- * @throws ExecutionException If the computation threw an exception.
- * @throws InterruptedException If the current thread was interrupted
- * while waiting.
- */
- public final Result get() throws InterruptedException, ExecutionException {
- return mFuture.get();
- }
-
- /**
- * Waits if necessary for at most the given time for the computation
- * to complete, and then retrieves its result.
- *
- * @param timeout Time to wait before cancelling the operation.
- * @param unit The time unit for the timeout.
- *
- * @return The computed result.
- *
- * @throws CancellationException If the computation was cancelled.
- * @throws ExecutionException If the computation threw an exception.
- * @throws InterruptedException If the current thread was interrupted
- * while waiting.
- * @throws TimeoutException If the wait timed out.
- */
- public final Result get(long timeout, TimeUnit unit) throws InterruptedException,
- ExecutionException, TimeoutException {
- return mFuture.get(timeout, unit);
- }
-
- /**
- * Executes the task with the specified parameters. The task returns
- * itself (this) so that the caller can keep a reference to it.
- *
- * Note: this function schedules the task on a queue for a single background
- * thread or pool of threads depending on the platform version. When first
- * introduced, AsyncTasks were executed serially on a single background thread.
- * Starting with {@link android.os.Build.VERSION_CODES#DONUT}, this was changed
- * to a pool of threads allowing multiple tasks to operate in parallel. Starting
- * {@link android.os.Build.VERSION_CODES#HONEYCOMB}, tasks are back to being
- * executed on a single thread to avoid common application errors caused
- * by parallel execution. If you truly want parallel execution, you can use
- * the {@link #executeOnExecutor} version of this method
- * with {@link #THREAD_POOL_EXECUTOR}; however, see commentary there for warnings
- * on its use.
- *
- *
This method must be invoked on the UI thread.
- *
- * @param params The parameters of the task.
- *
- * @return This instance of AsyncTask.
- *
- * @throws IllegalStateException If {@link #getStatus()} returns either
- * {@link AsyncTask.Status#RUNNING} or {@link AsyncTask.Status#FINISHED}.
- *
- * @see #executeOnExecutor(java.util.concurrent.Executor, Object[])
- * @see #execute(Runnable)
- */
- public final AsyncTask execute(Params... params) {
- return executeOnExecutor(sDefaultExecutor, params);
- }
-
- /**
- * Executes the task with the specified parameters. The task returns
- * itself (this) so that the caller can keep a reference to it.
- *
- * This method is typically used with {@link #THREAD_POOL_EXECUTOR} to
- * allow multiple tasks to run in parallel on a pool of threads managed by
- * AsyncTask, however you can also use your own {@link Executor} for custom
- * behavior.
- *
- *
Warning: Allowing multiple tasks to run in parallel from
- * a thread pool is generally not what one wants, because the order
- * of their operation is not defined. For example, if these tasks are used
- * to modify any state in common (such as writing a file due to a button click),
- * there are no guarantees on the order of the modifications.
- * Without careful work it is possible in rare cases for the newer version
- * of the data to be over-written by an older one, leading to obscure data
- * loss and stability issues. Such changes are best
- * executed in serial; to guarantee such work is serialized regardless of
- * platform version you can use this function with {@link #SERIAL_EXECUTOR}.
- *
- *
This method must be invoked on the UI thread.
- *
- * @param exec The executor to use. {@link #THREAD_POOL_EXECUTOR} is available as a
- * convenient process-wide thread pool for tasks that are loosely coupled.
- * @param params The parameters of the task.
- *
- * @return This instance of AsyncTask.
- *
- * @throws IllegalStateException If {@link #getStatus()} returns either
- * {@link AsyncTask.Status#RUNNING} or {@link AsyncTask.Status#FINISHED}.
- *
- * @see #execute(Object[])
- */
- public final AsyncTask executeOnExecutor(Executor exec,
- Params... params) {
- if (mStatus != Status.PENDING) {
- switch (mStatus) {
- case RUNNING:
- throw new IllegalStateException("Cannot execute task:"
- + " the task is already running.");
- case FINISHED:
- throw new IllegalStateException("Cannot execute task:"
- + " the task has already been executed "
- + "(a task can be executed only once)");
- }
- }
-
- mStatus = Status.RUNNING;
-
- onPreExecute();
-
- mWorker.mParams = params;
- exec.execute(mFuture);
-
- return this;
- }
-
- /**
- * Convenience version of {@link #execute(Object...)} for use with
- * a simple Runnable object. See {@link #execute(Object[])} for more
- * information on the order of execution.
- *
- * @see #execute(Object[])
- * @see #executeOnExecutor(java.util.concurrent.Executor, Object[])
- */
- public static void execute(Runnable runnable) {
- sDefaultExecutor.execute(runnable);
- }
-
- /**
- * This method can be invoked from {@link #doInBackground} to
- * publish updates on the UI thread while the background computation is
- * still running. Each call to this method will trigger the execution of
- * {@link #onProgressUpdate} on the UI thread.
- *
- * {@link #onProgressUpdate} will note be called if the task has been
- * canceled.
- *
- * @param values The progress values to update the UI with.
- *
- * @see #onProgressUpdate
- * @see #doInBackground
- */
- protected final void publishProgress(Progress... values) {
- if (!isCancelled()) {
- sHandler.obtainMessage(MESSAGE_POST_PROGRESS,
- new AsyncTaskResult