Detecting touch event outside certain UIView

Detecting touch event outside certain UIView

In my app, to click a button will pop up a UIView, now I want to click
anywhere outside of the UIView to dismiss the UIView.
I have tried adding a large transparent button under the UIView, invoke
the button action to dismiss the UIView, but the button can't be expanded
to Fullscreen because of the top navigationbar and bottom tabbar
Is any other way to achieve?