Android Button onTouch(), if return true, has no click animation effect; if return false, has clik animation effect

Question

I observe this weird behavior, please help me figure it out!

I simply set a onTouchListner to a button. For the onTouch() callback, if I set it return false, when I click on the button, I can see the click animation effect of the button (simply color change); However, if I set it return true, when I click on the button, the click animation effect just disappeared.

Below is the code

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button btn = findViewById(R.id.btn);
        btn.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                v.setClickable(true);
                Log.d("myTrack", "onTouch");
                return true;  // I cannot see the animation effect when click
                return false; // I can see the animation effect when click
            }
        });
    }
}

Answer 1

I observe this weird behavior, please help me figure it out!

This is default behaviour of Android.

If you return true from an ACTION_DOWN event you are interested in the rest of the events in that gesture. A "gesture" in this case means all events until the final ACTION_UP or ACTION_CANCEL . Returning false from an ACTION_DOWN means you do not want the event and other views will have the opportunity to handle it. If you have overlapping views this can be a sibling view. If not it will bubble up to the parent.

So when you return true , you have told android that you have handled all events, and it has nothing to do with. So you don't see any ripple effects even.