Android Async task cancel/stop

Question

I want to know what is the best way to stop an async task frm running.

I have tried

@Override protected void onCancelled() { 
      super.onCancelled(); 
      mTask.cancel(true);       
 }

I also tried

asyncTaskObject.cancel(true);

This works specially when associated with an event.

But suppose the scenario is--- there are 4 AsyncTask. First call the second, second calls the third and third calls fourth. When the user enters the activity there is no dialogbox. Otherwise we could have used the onCancel method there. When user clicks on anywhere on the page the dialog box appears if user does not click anywhere then no dialog box is shown but async task keep running in the background.Suppose the user clicks the "back" button on or the navigational icon to the home page user.is taken out of the current activity. But the async task keep running in the background and eventually the app crashes. I have used to the cancel method in onBackPressed. But the problem is you cannot be sure which task is running and app carshes again.

What is the way out of this?

Answer 1

keep reference to AsyncTask object as instance variable and then in onDestroy() do this

@Override
protected void onDestroy() {
    if (mTask != null) {
        mTask.cancel(true);
    }

    super.onDestroy();
}