How can i stop a TimerTask Handler?

Question

I am trying to stop a Timer or TimerTask, but the method doesn't destroy the task...

First the code how i set up the timertask:

 scanTask = new TimerTask() {
    public void run() {
            handler.post(new Runnable() {
                    public void run() {
                     load_unread();
                     Log.d("TIMER", "Timer set off");
                    }
           });
    }};

t=new Timer(); t.schedule(scanTask, 300, 10000);

and now I'm trying to "kill" this Task at onDestroy:

@Override
protected void onDestroy() {
    super.onDestroy();
    scanTask.cancel();
    t.cancel();
    t.purge();
    handler.removeCallbacksAndMessages(null);
    System.out.println("Chat destroyed");
}

but this doesn't work? Can you please help me finding a solution?

Thanks!

EDIT: I finally found the answer. Don't know why mine didn't work...

Here the code for everyone who has the same Problem. I think this is a better and more efficient solution anyway:

private Handler handler = new Handler(); runnable.run();

private Runnable runnable = new Runnable() 
{

    public void run() 
    {
         //
         // Do the stuff
         //

         handler.postDelayed(this, 1000);
    }
};

and to stop:

handler.removeCallbacks(runnable);

taken from here:

https://stackoverflow.com/a/11640073/1956197

Why doesn'it it work? Is it running, or are you getting an error? — Yaroslav Mytkalyk, Feb 04 '13 at 18:26
It is running. there are no errors at all, but in my log I'm still getting this "timer set off" from the runnable. — Matthew Fisher, Feb 04 '13 at 18:29
So, you get "Chat destroyed" in log, and after that "timer set off", and the activity with the timer was not restarted, correct? Pretty weird, if yes. — Yaroslav Mytkalyk, Feb 04 '13 at 18:35
exactly thats the problem... if my activity was restarted,i would get enother log because I'm catching the OnResume also... — Matthew Fisher, Feb 04 '13 at 19:55
is there another way to make a repeating function which i can cancel easier? — Matthew Fisher, Feb 04 '13 at 20:40
You can try handler postDelayed, and in handleMessage make postDelayed again to itself thus making an infinite posting. — Yaroslav Mytkalyk, Feb 05 '13 at 09:46

score 2 · Answer 1 · answered Feb 05 '13 at 17:45

After looking at your edit, the only thing I'd suggest is to use handler.post(runnable); instead of runnable.run(); This way you are always executing your runnable on a separate thread. Otherwise, your first execution will run on the main thread, then future executions run inside the handler on a separate thread.

    final Handler handler = new Handler();

    Runnable runnable = new Runnable() {

        public void run() {
            //
            // Do the stuff
            //

            handler.postDelayed(this, 1000);
        }
    };

    handler.post(runnable);

oh ok that seems logic, this may have been the problem! – Matthew Fisher Feb 05 '13 at 17:56 — Matthew Fisher, Feb 05 '13 at 17:56

score 0 · Answer 2 · answered Feb 04 '13 at 18:38

0

Cancel the TimerTask before setting it to null.

scanTask.cancel();

answered Feb 04 '13 at 18:38

invertigo

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score 0 · Answer 3 · answered Jun 19 '20 at 12:25

this example start the timer unitl destroyed

 private lateinit var timerTask: TimerTask

 timerTask = object : TimerTask() {
        override fun run() {
            Log.d("KTZ", "$minutes:$seconds");
            timeRecordingLiveData.postValue("$minutes:$seconds")
            seconds += 1;
            if (seconds == 60) {
                Log.d("KTZ", "$minutes:$seconds");
                timeRecordingLiveData.postValue("$minutes:$seconds")
                seconds = 0;
                minutes += 1;
            }
        }

    }

Cancel the timertask in onDestroy()

    timerTask.cancel()

How can i stop a TimerTask Handler?

3 Answers3