有时无法收到ACTION_UP或ACTION_CANCEL

Question

I made an app that has a couple of buttons that get smaller when pressed in order to simulate a physical button going down.

Everything works as intended, but unfortunately, during IRL testing with users, we find that sometimes the button doesn't pop back up! (But only sometimes - like 5% chance)

We have no idea what is causing this anomaly, and was wondering if anyone could shed some light on this.

Currently we are assuming its because ACTION_UP || ACTION_CANCEL ACTION_UP || ACTION_CANCEL isn't being called in some edge case - but we are not sure.

public class MainActivity extends CustomActivity
{
    public AppCompatButton myButton;

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

        myButton = (AppCompatButton) findViewById(R.id.my_button);

        myButton.setOnClickListener(myClickListener); // handle the actual click
        myButton.setOnTouchListene(myTouchListener); // simulate press down
    }

    ...

    private View.OnTouchListener myTouchListener = new View.OnTouchListener()
    {
        @Override
        public boolean onTouch(View v, MotionEvent event)
        {
            int action = event.getAction();

            if (action == MotionEvent.ACTION_DOWN)
            {
                ObjectAnimator scaleDownX = ObjectAnimator.ofFloat(v, "scaleX", 0.7f);
                ObjectAnimator scaleDownY = ObjectAnimator.ofFloat(v, "scaleY", 0.7f);

                scaleDownX.setDuration(120);
                scaleDownY.setDuration(120);

                AnimatorSet scaleDown = new AnimatorSet();
                scaleDown.play(scaleDownX).with(scaleDownY);

                scaleDown.start();
            }

            if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL)
            {
                ObjectAnimator scaleUpX = ObjectAnimator.ofFloat(v, "scaleX", 1);
                ObjectAnimator scaleUpY = ObjectAnimator.ofFloat(v, "scaleY", 1);

                scaleUpX.setDuration(100);
                scaleUpY.setDuration(100);

                AnimatorSet scaleUp = new AnimatorSet();
                scaleUp.play(scaleUpX).with(scaleUpY);

                scaleUp.start();
            }

            return false;
        }
    };
}

Answer 1

I tested your code. It's working perfectly for me. If you still getting issues with it, I suggest you to use Rebound - Spring animations for android

Answer 2

Problem solved. ACTION_UP and ACTION_CANCEL were being called. The problem lies in the interaction between scaleDown.start(); and scaleUp.start(); .

If they occur immedietly after one and another, scaleUp.start(); does not automatically override scaleDown.start(); and thus your button is left stuck "down".

SOLUTION: use facebook's spring library.