How to give back swipe gesture in SwiftUI the same behaviour as in UIKit (interactivePopGestureRecognizer)

Question

The interactive pop gesture recognizer should allow the user to go back the the previous view in navigation stack when they swipe further than half the screen (or something

Answer 1

I ended up overriding the default NavigationView and NavigationLink to get the desired behaviour. This seems so simple that I must be overlooking something that the default SwiftUI views do?

NavigationView

I wrap a UINavigationController in a super simple UIViewControllerRepresentable that gives the UINavigationController to the SwiftUI content view as an environmentObject. This means the NavigationLink can later grab that as long as it's in the same navigation controller (presented view controllers don't receive the environmentObjects) which is exactly what we want.

Note: The NavigationView needs .edgesIgnoringSafeArea(.top) and I don't know how to set that in the struct itself yet. See example if your nvc cuts off at the top.

struct NavigationView: UIViewControllerRepresentable {

    var content: () -> Content

    init(@ViewBuilder content: @escaping () -> Content) {
        self.content = content
    }

    func makeUIViewController(context: Context) -> UINavigationController {
        let nvc = UINavigationController()
        let host = UIHostingController(rootView: content().environmentObject(nvc))
        nvc.viewControllers = [host]
        return nvc
    }

    func updateUIViewController(_ uiViewController: UINavigationController, context: Context) {}
}

extension UINavigationController: ObservableObject {}

NavigationLink

I create a custom NavigationLink that accesses the environments UINavigationController to push a UIHostingController hosting the next view.

Note: I didn't implement the selection and isActive that the SwiftUI.NavigationLink has because I don't fully understand what they do yet. If you want to help with that please comment/edit.

struct NavigationLink: View {
    var destination: Destination
    var label: () -> Label

    public init(destination: Destination, @ViewBuilder label: @escaping () -> Label) {
        self.destination = destination
        self.label = label
    }

    /// If this crashes, make sure you wrapped the NavigationLink in a NavigationView
    @EnvironmentObject var nvc: UINavigationController

    var body: some View {
        Button(action: {
            let rootView = self.destination.environmentObject(self.nvc)
            let hosted = UIHostingController(rootView: rootView)
            self.nvc.pushViewController(hosted, animated: true)
        }, label: label)
    }
}

This solves the back swipe not working correctly on SwiftUI and because I use the names NavigationView and NavigationLink my entire project switched to these immediately.

Example

In the example I show modal presentation too.

struct ContentView: View {
    @State var isPresented = false

    var body: some View {
        NavigationView {
            VStack(alignment: .center, spacing: 30) {
                NavigationLink(destination: Text("Detail"), label: {
                    Text("Show detail")
                })
                Button(action: {
                    self.isPresented.toggle()
                }, label: {
                    Text("Show modal")
                })
            }
            .navigationBarTitle("SwiftUI")
        }
        .edgesIgnoringSafeArea(.top)
        .sheet(isPresented: $isPresented) {
            Modal()
        }
    }
}

struct Modal: View {
    @Environment(\.presentationMode) var presentationMode

    var body: some View {
        NavigationView {
            VStack(alignment: .center, spacing: 30) {
                NavigationLink(destination: Text("Detail"), label: {
                    Text("Show detail")
                })
                Button(action: {
                    self.presentationMode.wrappedValue.dismiss()
                }, label: {
                    Text("Dismiss modal")
                })
            }
            .navigationBarTitle("Modal")
        }
    }
}

---

Edit: I started off with "This seems so simple that I must be overlooking something" and I think I found it. This doesn't seem to transfer EnvironmentObjects to the next view. I don't know how the default NavigationLink does that so for now I manually send objects on to the next view where I need them.

NavigationLink(destination: Text("Detail").environmentObject(objectToSendOnToTheNextView)) {
    Text("Show detail")
}

Edit 2:

This exposes the navigation controller to all views inside NavigationView by doing @EnvironmentObject var nvc: UINavigationController. The way to fix this is making the environmentObject we use to manage navigation a fileprivate class. I fixed this in the gist: https://gist.github.com/Amzd/67bfd4b8e41ec3f179486e13e9892eeb