How to make the Handler method be destroyed when the activity finishes?

Question

At the end of this activity, the timer from the Handler method continues. How to make the Handler method be destroyed when the activity finishes?

                 Handler handler = new Handler();
                    handler.postDelayed(new Runnable() {
                        public void run() {
                            mTextViewCountDown.setTextColor(Color.RED);
                        }
                    }, 55000);

Answer 1

In my case I did not "destroy" the method if I leave the Activity, but the method does something only when Activity is active

Something like this :

// Variable of your activity
private static boolean active = false;

Handler handler = new Handler();
                    handler.postDelayed(new Runnable() {
                        public void run() {
                            // do something only if Activity is active
                            if(active) {
                                mTextViewCountDown.setTextColor(Color.RED);
                            }
                        }
                    }, 55000);

and set the value of active in the onStart / onStop methods :

@Override
    public void onStart() {
        super.onStart();
        active = true;
    }

    @Override
    public void onStop() {
        super.onStop();
        active = false;
    }

this way the code inside handler.postdelay will be executed only when your Activity is active

Answer 2

you can you use onDestory(); lifecycle method.this method calls when an activity going to finish and in this activity lifecycle method you and stop the handler like this

@Override 
protected void onDestroy() {

Handler handler = new Handler();

handler.postDelayed(new Runnable());

super.onDestroy();

}```