The approach I’m gonna introduce is just simply updating the fixed footer’s frame, making sure the fixed view is located where it should be, whenever the UIScrollView is scrolled.
The trick is overriding layoutSubviews() of UIScrollView:
...
/* Our fixed footer is declared here. */
var footerBar: UIView!
...
/* This method is called when subviews have to be layouted. */
override func layoutSubviews() {
super.layoutSubviews()
/* Where the fixed view should be. */
let location = CGPointMake(0, contentOffset.y - footerBar.frame.height + self.frame.height)
/* Update footerBar's location. */
footerBar.frame.origin = location
}
...