LargeTitles UIScrollView does not support multiple observers implementing _scrollViewWillEndDraggingWithVelocity:targetContentOffset

Question

I have implemented large titles in my app with the following code:

if #available(iOS 11.0, *) {
            navigationController?.navigationBar.prefersLargeTitle         


        

Answer 1

The problem happened when the tableview was still scrolling when I went to another view. I fixed the problem by setting a bool in the scrollViewDidScroll that disables any scrolling when the segue is started.

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        if viewIsVisible {
            if scrollView.contentOffset.y <= 0 {
                if #available(iOS 11.0, *) {
                    self.navigationItem.largeTitleDisplayMode = .always
                } else {
                    // Fallback on earlier versions
                }
            } else {
                if #available(iOS 11.0, *) {
                    self.navigationItem.largeTitleDisplayMode = .never
                } else {
                    // Fallback on earlier versions
                }
            }
            self.navigationController?.navigationBar.setNeedsLayout()
            self.view.setNeedsLayout()
            UIView.animate(withDuration: 0.01, animations: {
                self.navigationController?.navigationBar.layoutIfNeeded()
                self.view.layoutIfNeeded()
            })
        }
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        self.viewIsVisible = false
}