DVOBouncer : Add Gravity Bouncing to UIScrollView Content
DVOBouncer lets you add gravity bouncing to UIScrollView content. It can be useful in certain scenarios like when you want to show the user that there is more content on another side of the scroll view (Click on the image to view the animation in action).
It uses UIKit Dynamics to simulate an elastic bounce effect on scroll view content in any direction. Its usage is very simple and can be implemented in one line (see below),
self.bouncer = [DVOBouncer bounceScrollView:scrollView inDirection:DVOBounceDirectionBottom];