// Swift 5
self.scrollView.delegate = self
// Changed the page property when the user scrolls over 50% of the current page.
// Page starts with 0
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let scrollViewWidth = scrollView.bounds.width
self.page = Int(round(scrollView.contentOffset.x / scrollViewWidth))
}
var page: Int {
didSet {
guard oldValue != self.page else {
return
}
// Handle page update
}
}