Stop AsyncTask in Fragments when Back Button is pressed

Question

i have an activities that host fragments. pressing a button goes from fragment A to fragment B through a FragmentTransaction and the added to the back stack. Now fragment B

Answer 1

    AsyncTaskRunner doAsynchronousTask; //Before onCreateView

//in onCreateView() 
    doAsynchronousTask = new AsyncTaskRunner();``
    doAsynchronousTask.execute();


// after  onCreateView()
    @Override
    public void onStop() {
        super.onStop();
        doAsynchronousTask.cancel(true);
    }