Question

In my android app, let’s say I have 2 buttons, the first button will start the while loop and the second will stop it, and a method do_something() that I will need to execute over and over again continuously.

public void onCreate() {
        my_var = true;
        ok = (Button)findViewById(R.id.button1);
        ok.setOnTouchListener(new OnTouchListener() {

            @Override
            public boolean onTouch(View v, MotionEvent event) {


                if (event.getAction() == MotionEvent.ACTION_DOWN) {
                    while(my_var) do_something();
                }

                return true;
            }
        });

        stop = (Button)findViewById(R.id.button2);
        stop.setOnTouchListener(new OnTouchListener() {

            @Override
            public boolean onTouch(View v, MotionEvent event) {


                if (event.getAction() == MotionEvent.ACTION_DOWN) {
                    my_var = false;
                }

                return true;
            }
        });

the following is causing my application and my entire phone to just freeze up. Can anyone at a glance tell what I am doing incorrectly? aLogCat isn’t giving me much info.
Any help would be much appreciated!

Answer 1

It freezes because the loop executes on UI thread and UI can’t process events to stop it. Consequently, it can’t be stopped. You must use different thread for such occasion.