Detecting UIScrollView page change

Question

Is there a way to detect or get a notification when user changes the page in a paging-enabled UIScrollView?

Answer 1

var scrollViewPage = 0
override func viewDidLoad() {
    super.viewDidLoad()
    scrollViewPage = scrollView.currentPage
}

func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
    if scrollViewPage != scrollView.currentPage {
        scrollViewPage = scrollView.currentPage
        // Do something with your page update
        print("scrollViewDidEndDecelerating: \(scrollViewPage)")
    }
}

And Use extension

extension UIScrollView {
    var currentPage: Int {
        return Int((self.contentOffset.x + (0.5 * self.frame.size.width)) / 
        self.frame.width) + 1
    }
}