Android: Why can't I create a handler in new thread

Question

I had a problem creating a handler in new thread. This is my code:

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(         


        

Answer 1

The Thread's lifecycle is finished right after run method returns. But since you are creating a Handler in this thread, the Handler needs the thread to be running for it to receive messages and process them.

So for this to happen, run method should not exit. Hence you need a Looper to wait indefinitely and process messages that arrive to Handler.

new Thread(new Runnable() {
        public void run() {
            Looper.prepare();
            Handler handler = new Handler();
            Looper.loop();
        }
    }).start();