android.os.AsyncTask#cancel ( )源码实例Demo

private void getAddressByGeoCodingLatLng() {

        //Get string address by geo coding from lat long
        if (mLatitude != 0 && mLongitude != 0) {

            if (MapUtility.popupWindow != null && MapUtility.popupWindow.isShowing()) {
                MapUtility.hideProgress();
            }

            Log.d(TAG, "getAddressByGeoCodingLatLng: START");
            //Cancel previous tasks and launch this one
            for (AsyncTask prevTask : filterTaskList) {
                prevTask.cancel(true);
            }

            filterTaskList.clear();
            GetAddressFromLatLng asyncTask = new GetAddressFromLatLng();
            filterTaskList.add(asyncTask);
            asyncTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, mLatitude, mLongitude);
        }
    }
 

private synchronized void cancel() {
    AsyncTask<?, ?, ?> task = inactivityTask;
    if (task != null) {
        task.cancel(true);
        inactivityTask = null;
    }
}
 

@Override
protected void onDestroy() {
    super.onDestroy();
    for (AsyncTask task : filterTaskList) {
        task.cancel(true);
    }
}
 

private synchronized void cancel() {
  AsyncTask<?,?,?> task = inactivityTask;
  if (task != null) {
    task.cancel(true);
    inactivityTask = null;
  }
}
 

private synchronized void cancel() {
    AsyncTask<?, ?, ?> task = inactivityTask;
    if (task != null) {
        task.cancel(true);
        inactivityTask = null;
    }
}
 

/**
 * 取消计时任务
 */
private synchronized void cancel() {
    AsyncTask<?, ?, ?> task = mInactivityTask;
    if (task != null) {
        task.cancel(true);
        // 重置为 null
        mInactivityTask = null;
    }
}
 

private synchronized  void cancel() {
  AsyncTask<?,?,?> task = inactivityTask;
  if (task != null) {
    task.cancel(true);
    inactivityTask = null;
  }
}
 

private synchronized void cancel() {
  AsyncTask<?,?,?> task = inactivityTask;
  if (task != null) {
    task.cancel(true);
    inactivityTask = null;
  }
}
 

/**
 * Call cancel on all tasks and then wipe the living task list.
 */
public static void cancelTasks() {
    synchronized (livingTasks) {
        for (AsyncTask task : livingTasks) {
            task.cancel(true);
        }
        livingTasks.clear();
    }
}
 

@Override
protected void onPause() {
  AsyncTask<?,?,?> oldTask = networkTask;
  if (oldTask != null) {
    oldTask.cancel(true);
    networkTask = null;
  }
  super.onPause();
}
 

@Override
protected void onPause() {
  AsyncTask<?,?,?> task = backgroundTask;
  if (task != null) {
    task.cancel(true);
    backgroundTask = null;
  }
  super.onPause();
}
 

private void launchSearch() {
  String query = queryTextView.getText().toString();
  if (query != null && !query.isEmpty()) {
    AsyncTask<?,?,?> oldTask = networkTask;
    if (oldTask != null) {
      oldTask.cancel(true);
    }
    networkTask = new NetworkTask();
    networkTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, query, isbn);
    headerView.setText(R.string.msg_sbc_searching_book);
    resultListView.setAdapter(null);
    queryTextView.setEnabled(false);
    queryButton.setEnabled(false);
  }
}
 

void cancelTasks() {
    for (AsyncTask task : taskList) {
        task.cancel(true);
    }

    taskList.clear();
}
 

/**
 * 如果任务未执行完毕，则取消任务
 *
 * @param clazz Activity Class
 */
public void unregisterAsyncTask(Class<? extends BaseActivity> clazz) {
    ArrayList<AsyncTask> tasks = new ArrayList<>(mTasks.removeAll(clazz));
    int size = tasks.size();
    if (size > 0) {
        for (int i = 0; i < size; i++) {
            AsyncTask task = tasks.get(i);
            //you may call the cancel() method but if it is not handled in doInBackground() method
            if (task != null && task.getStatus() != AsyncTask.Status.FINISHED) {
                task.cancel(true);
            }
        }
    }
}
 

@Override
protected void onPause() {
  AsyncTask<?,?,?> oldTask = networkTask;
  if (oldTask != null) {
    oldTask.cancel(true);
    networkTask = null;
  }
  super.onPause();
}
 

@Override
protected void onPause() {
  AsyncTask<?,?,?> oldTask = networkTask;
  if (oldTask != null) {
    oldTask.cancel(true);
    networkTask = null;
  }
  super.onPause();
}
 

@Override
protected void onPause() {
  AsyncTask<?,?,?> task = backgroundTask;
  if (task != null) {
    task.cancel(true);
    backgroundTask = null;
  }
  super.onPause();
}
 

private synchronized void cancel() {
	AsyncTask<?, ?, ?> task = inactivityTask;
	if (task != null) {
		task.cancel(true);
		inactivityTask = null;
	}
}
 

@CallSuper
@Override
public void destroy() {
    for (AsyncTask asyncTask : asyncTasks) {
        asyncTask.cancel(true);
    }
    asyncTasks.clear();
}
 

private void cancelAsyncTask(AsyncTask task) {
    if (task != null) task.cancel(false);
}