Android: Detect if user touches and drags out of button region?

Question

In Android, how can we detect if a user touches on button and drags out of region of this button?

Answer 1

view.setClickable(true);
view.setOnTouchListener(new OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (!v.isPressed()) {
            Log.e("onTouch", "Moved outside view!");
        }
        return false;
    }
});

view.isPressed uses view.pointInView and includes some touch slop. If you don't want slop, just copy the logic from the internal view.pointInView (which is public, but hidden so it's not a part of the official API and could disappear at any time).

view.setClickable(true);
view.setOnTouchListener(new OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_DOWN) {
            v.setTag(true);
        } else {
            boolean pointInView = event.getX() >= 0 && event.getY() >= 0
                    && event.getX() < (getRight() - getLeft())
                    && event.getY() < (getBottom() - getTop());
            boolean eventInView = ((boolean) v.getTag()) && pointInView;
            Log.e("onTouch", String.format("Dragging currently in view? %b", pointInView));
            Log.e("onTouch", String.format("Dragging always in view? %b", eventInView));
            v.setTag(eventInView);
        }
        return false;
    }
});

Answer 2

I added some logging in my OnTouch and found out that MotionEvent.ACTION_CANCEL was being hit. That's good enough for me...

Answer 3

The top 2 answers are fine except when the view is inside a scrollview: when scrolling takes place because you move your finger, it is still registered as a touch event but not as a MotionEvent.ACTION_MOVE event. So to improve the answer (which is only needed if your view is inside a scroll element):

private Rect rect;    // Variable rect to hold the bounds of the view

public boolean onTouch(View v, MotionEvent event) {
    if(event.getAction() == MotionEvent.ACTION_DOWN){
        // Construct a rect of the view's bounds
        rect = new Rect(v.getLeft(), v.getTop(), v.getRight(), v.getBottom());

    } else if(rect != null && !rect.contains(v.getLeft() + (int) event.getX(), v.getTop() + (int) event.getY())){
        // User moved outside bounds
    }
    return false;
}

I tested this on Android 4.3 and Android 4.4

I haven't noticed any differences between Moritz's answer and to top 2 but this also applies for his answer:

private Rect rect;    // Variable rect to hold the bounds of the view

public boolean onTouch(View v, MotionEvent event) {
    if(event.getAction() == MotionEvent.ACTION_DOWN){
        // Construct a rect of the view's bounds
        rect = new Rect(v.getLeft(), v.getTop(), v.getRight(), v.getBottom());

    } else if (rect != null){
        v.getHitRect(rect);
        if(rect.contains(
                Math.round(v.getX() + event.getX()),
                Math.round(v.getY() + event.getY()))) {
            // inside
        } else {
            // outside
        }
    }
    return false;
}