Executing code when the scrollview swipes

How ca开发者_开发知识库n code be linked to the swipes of a UIScrollView?

If the user swipes left I would like to decrement a counter and vice versa.

If your counter value is tied to contents offset then you can set UIScrollView's delegate and implement scrollViewDidScroll: method in it. There you can check contentOffset value and change your counter accordingly.