这是通过触摸导航栏中间的按钮来显示视图并通过触摸其他任何位置删除它的好方法吗？

I'm trying to put a button at the middle of the navigation bar, it will show a list when I touch it (I added a pure UIView here instead of a UITabeView to just make the code simpler) . And then the additional view will be removed when I touch anywhere else. So I add a background view whose size is the same as the screen to response my touch. Although it still behind the navigation bar. I'm trying to put a button at the middle of the