How detect when we were dragging ListView edges?

Question

I don't know how to detect when we were dragging ListView edges.

http://imgur.com/PCCgkEC

// edit

event1 - listview on panel

event2 - main panel

    event1.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
             if ( ##listview on top end when we drag to down ) {
                  return event2.onTouchEvent(event);
             } else {
                  return event1.onTouchEvent(event)
             }
        }
    });