code: void handleMoveEvent(@NonNull final MotionEvent ev) {
          int top = (int) (mOriginalY - mDownY + ev.getY() + mScrollDistance);
          setTop(top);
      }
docs: Calculates the new position for this {@code HoverDrawable} using given {@link MotionEvent}.
  
  @param ev the {@code MotionEvent}.
  {@code ev.getActionMasked()} should typically equal {@link MotionEvent#ACTION_MOVE}.