code: private void onScrollPositionChanged(int oldScrollPosition, int newScrollPosition) {
  		int newScrollDirection;
  
  		if (newScrollPosition < oldScrollPosition) {
  			newScrollDirection = SCROLL_TO_TOP;
  		} else {
  			newScrollDirection = SCROLL_TO_BOTTOM;
  		}
  
  		if (directionHasChanged(newScrollDirection)) {
  			translateYAnimatedView(newScrollDirection);
  		}
  	}
docs: Perform the "translateY" animation using the new scroll position and the old scroll position to show or hide
  the animated view.
  
  @param oldScrollPosition
  @param newScrollPosition