What's the best way to stop a scrolling layer at a certain point. As you can see in the video, what I'am trying to do is stopping the button on the top of the view. The button as the other elements are sublayer of a bigger transparent layer where the scroll event is applied. Right now I am animating the button trough next states but as you can see is pretty buggy and it's hard to guess the exact speed and curve of the scrolling animation. Thanks a lot guys!