Why use HandlerThread in Android

Question

In android , Handler can be used to post / handle message, if I don\'t use a HandlerThread (pass its Looper to Handler), does that mean in this case Handler use MainThread (

Answer 1

Normal way to use HandlerThread like this:

HandlerThread thread = new HandlerThread("A Handler Thread");
thread.start();
Handler handler = new Handler(thread.getLooper()){
    @Override
    public void handleMessage(Message msg) 
    {
    //....
    }
};

Because HandlerThread can create a Looper for Handler, it is a kind of convenient way.

When you create a new Handler, it is bound to the thread / message queue of the thread that is creating it -- see official docs...