Fatal error: No ObservableObject of type NavigationStack found.

[blainesolomon]

Open curiosity: Is there a way to use this inside of a modal or nav view? (Works well otherwise)

If I attempt either, I get the following error:

Fatal error: No ObservableObject of type NavigationStack found.

I'm down to try anything as a potential workaround

[matteopuc]

Hi @blainesolomon, thanks for asking. Your question is actually very interesting. In SwiftUI a modal view (presented with the .sheet modifier) opens a new view hierarchy. A NavigationStackView works for its view hierarchy. I mean: if you do something like:

struct RootView : View {
    var body: some View {
        NavigationStackView {
            Homepage()
        }
    }
}

That NavigationStackView will work for that specific hierarchy. But if you want to have a navigation flow in a modal view you can wrap your modal content in a new NavigationStackView, basically creating another navigation flow. Take a look at this example:

import SwiftUI
import NavigationStack

struct ContentView : View {
    var body: some View {
        NavigationStackView {
            ZStack {
                Color.green.edgesIgnoringSafeArea(.all)
                PushView(destination: Child()) {
                    Text("PUSH!")
                }
            }
        }
    }
}

struct Child : View {
    @State private var modalIsActive = false

    var body: some View {
        ZStack {
            Color.yellow.edgesIgnoringSafeArea(.all)
            VStack {
                Text("Hello World")
                    .sheet(isPresented: $modalIsActive) {
                        NavigationStackView {
                            ModalView()
                        }
                    }
                PopView {
                    Text("POP")
                }
                Button(action: {
                    self.modalIsActive = true
                }, label: {
                    Text("OPEN MODAL")
                })
            }
        }
    }
}

struct ModalView : View {
    var body: some View {
        ZStack {
        Color.red.edgesIgnoringSafeArea(.all)
            VStack {
                Text("MODAL VIEW")
                PushView(destination: ModalChild()) {
                    Text("PUSH TO MODAL CHILD")
                }
            }
        }
    }
}

struct ModalChild : View {
    var body: some View {
        ZStack {
            Color.blue.edgesIgnoringSafeArea(.all)
            VStack {
                Text("MODAL CHILD")
                PopView {
                    Text("POP")
                }
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

The result is:

If you want, instead, to use the NavigationStackView inside the SwiftUI standard NavigationView things get complicated because every time you use the standard NavigationLink the framework creates a new view hierarchy. For example, if you write something like:

struct ContentView : View {
    var body: some View {
        NavigationStackView {
            NavigationView {
                ZStack {
                    Color.green.edgesIgnoringSafeArea(.all)
                    VStack {
                        PushView(destination: Child()) {
                            Text("PUSH WITH NavigationStackView!")
                        }
                        NavigationLink(destination: Child()) {
                            Text("PUSH WITH SwiftUI Standard navigation!")
                        }
                    }
                }
            }
        }
    }
}

struct Child : View {
    var body: some View {
        ZStack {
            Color.yellow.edgesIgnoringSafeArea(.all)
            VStack {
                Text("Hello World")
                PopView {
                    Text("POP")
                }
            }
        }
    }
}

and you "push" with the standard NavigationLink, you won't be able to come back with the PopView. You can wrap your Child view in a new NavigationStackView as in:

struct ContentView : View {
    var body: some View {
        NavigationStackView {
            NavigationView {
                ZStack {
                    Color.green.edgesIgnoringSafeArea(.all)
                    VStack {
                        PushView(destination: Child()) {
                            Text("PUSH WITH NavigationStackView!")
                        }
                        NavigationLink(destination: NavigationStackView { Child() }) {
                            Text("PUSH WITH SwiftUI Standard navigation!")
                        }
                    }
                }
            }
        }
    }
}

In this case you'll be able to push view from the child view on, but you won't be able to come back with the PopView to the ContentView because the two views belong to two different view hierarchies.

Matteo

[mustafaozhan]

@matteopuc @blainesolomon
you need to send your environmentObject to sheet like this

        .sheet(
            isPresented: $isBarShown,
            content: {
                BarView(
                    isBarShown: $isBarShown,
                    onDismiss: { observable.viewModel.verifyCurrentBase() }
                ).environmentObject(navigationStack)
            }
        )

After that it works perfectly fine 🙂