Pull-Down gesture not working with uipageViewController - ios

Question

I'm having a problem with the pull-down gesture that is not working. I'm presenting an UIPageViewController and each pages is a UIViewController containing an UITableView. when the transition style is set to pageCurl there is not problem with the pull-down gesture to dismiss but when the transition style is set to scroll, I can't dismiss the view. Only the UITableView is scrolling even when at the top
final class HistoryReceiptContainerViewController: UIPageViewController {
private let viewModel: HistoryReceiptContainerViewModel
init(viewModel: HistoryReceiptContainerViewModel) {
self.viewModel = viewModel
super.init(transitionStyle: .pageCurl, navigationOrientation: .horizontal, options: nil)
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
setViewControllers([receiptViewController(for: HistoryReceiptViewModel(historyId: "1234", source: "", context: nil, contextId: nil))], direction: .forward, animated: true, completion: nil)
}
private func receiptViewController(for viewModel: HistoryReceiptViewModel) -> HistoryReceiptViewController {
let vc = HistoryReceiptViewController(viewModel: viewModel)
return vc
}
}
And the code to present the view
present(HistoryReceiptContainerViewController(viewModel: viewModel)
Do you have any solutions for that kind of problem ?
Thank you in advance!
https://imgur.com/a/rwkVA0Q

Answer 1

Here is an example implementation to fix dismissing a UIPageViewController with transitionStyle .scroll by adding a UIPanGestureRecognizer and some custom gesture recognizer handling. It will work when pushing the UIPageViewController on a navigation stack as well as when presenting it modally.
class DemoPageViewController: UIPageViewController, UIGestureRecognizerDelegate {
var presentedModally = false
init(presentedModally: Bool = false) {
super.init(transitionStyle: .scroll, //if you would use .pageCurl dismissing works
navigationOrientation: .horizontal,
options: nil)
self.presentedModally = presentedModally
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func viewDidLoad() {
super.viewDidLoad()
setUpPanGestureForDismissingSelf()
}
// MARK: - UIGestureRecognizerDelegate
func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
guard let navigationController = navigationController, navigationController.interactivePopGestureRecognizer == gestureRecognizer else {
return true
}
return navigationController.viewControllers.count > 1
}
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldBeRequiredToFailBy otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return !presentedModally
}
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
return presentedModally
}
private func setUpPanGestureForDismissingSelf() {
guard presentedModally else { return }
let panGestureRecognizer = UIPanGestureRecognizer(target: self,
action: #selector(handlePanGesture(sender:)))
panGestureRecognizer.delegate = self
view.addGestureRecognizer(panGestureRecognizer)
}
#objc func handlePanGesture(sender: UIPanGestureRecognizer) {
let dragVelocity = sender.velocity(in: view)
if dragVelocity.y >= 1300 {
dismiss(animated: true)
}
}
}