How to cancel AsyncTask when Activity finishes?

Question

In my Activity I use multiple AsyncTask classes.

See http://stackoverflow.com/questions/2531336/asynctask-wont-stop-even-when-the-activity-has-destroyed — CommonsWare, Mar 28 '10 at 14:26
check this for a good example on correct way to cancel an asynctask http://www.quicktips.in/correct-way-to-cancel-an-asynctask-in-android/ — Deepak Swami, Jun 29 '16 at 17:09

score 7 · Answer 1 · answered Dec 13 '12 at 11:40

i think the best place to do this is onStop

protected void onStop() {
    super.onStop();

    /*
    * The device may have been rotated and the activity is going to be destroyed
    * you always should be prepared to cancel your AsnycTasks before the Activity
    * which created them is going to be destroyed.
    * And dont rely on mayInteruptIfRunning
    */
    if (this.loaderTask != null) {
        this.loaderTask.cancel(false);
    }
}

in my Task i then check as often as possible if cancel was called

protected String doInBackground(String... arg0) {
    if (this.isCancelled()) {
        return null;
    }
}

and of course dont forget to drop data that maybe returned since there's no more Activity to receive it

protected void onPostExecute(List<UserStatus> result) {
    if(!this.isCancelled()) {
        //pass data to receiver
    }
}

onPostExecute is never called with isCancelled is set to true. Instead a call is placed to onCancelled(Object) — Vihaan Verma, Feb 14 '14 at 07:08

score 2 · Accepted Answer · answered Mar 28 '10 at 14:26

2

I don't understand if your "cancel" means rollback but you have a cancel method on the AsyncTask class.

answered Mar 28 '10 at 14:26

Macarse

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After the task is finished I want it to disappear. – Pentium10 Mar 28 '10 at 14:35

score 2 · Answer 3 · answered Oct 17 '11 at 08:12

2

The asynctask thread is kept alive in a thread pool for future istances of AsyncTask. You can't remove them.

answered Oct 17 '11 at 08:12

STT LCU

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While this may be true, the question is about cancelling the task, not getting rid of its thread. – David Snabel-Caunt Oct 17 '11 at 11:27
Note @Pentium10 comment in the accepted answer - He wants the "task" (I believe meaning "thread") to "disappear. This is why I think this answer is best. – qxotk Apr 25 '12 at 22:27

How to cancel AsyncTask when Activity finishes?

3 Answers3

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