SwiftUI: NavigationView unexpectedly pops with nested Bindings when data changes

Using Swift
,
1

I have multiple scenes in a NavigationView accessed with NavigationLinks.

I have a struct with nested structs which correspond to the scenes.

At the root scene, I have a state struct, and the nested scenes have binding structs. When I’m three levels down in the navigation stack and I modify the data, the app unexpectedly jumps back to the previous scene. So if I have a TextField, then at each character press, the navigation stack jumps back, making the app unusable.

Is this the expected behaviour?

I created a bug report in case this isn't the expected behaviour: FB9771893

demo

This is the smallest project I could create to reproduce this problem.
My Model:

struct Name {
    var first: FirstName
    var last: String
}
struct FirstName {
    var name: String
    var origin: Location
}
struct Location {
    var country: String
    var city: String
}

My scenes:

struct ContentView: View {
    @State var name: Name = Name()
    
    var body: some View {
        NavigationView {
            NameScene(name: $name)            
        }
    }
}

struct NameScene: View {
    @Binding var name: Name
    
    var body: some View {
        Form {
            NavigationLink {
                FirstNameScene(firstName: $name.first)
            } label: {
                Text("First name")
            }

            TextField("Last name", text: $name.last)
        }
        .navigationTitle("Name Scene")
    }
}

struct FirstNameScene: View {
    @Binding var firstName: FirstName

    var body: some View {
        Form {
            TextField("First name", text: $firstName.name)
            NavigationLink {
                LocationScene(location: $firstName.origin)
            } label: {
                Text("Origin")
            }
        }
        .navigationTitle("First Name Scene")
    }
}

struct LocationScene: View {
    @Binding var location: Location
    
    var body: some View {
        Form {
            TextField("Country", text: $location.country)
            TextField("City", text: $location.city)            
        }
        .navigationTitle("Location Scene")
    }
}
2

Hi, this is not a bug, there are 2 ways to fix your problem:

  1. .isDetailLink(false) on the NavigationLink in NameScene.
  2. .navigationViewStyle(.stack) on the NavigationView.
struct Name {
    var first: FirstName = FirstName()
    var last: String = ""
}
struct FirstName {
    var name: String = ""
    var origin: Location = Location()
}
struct Location {
    var country: String = ""
    var city: String = ""
}

struct ContentView: View {
    @State var name: Name = Name()
    
    var body: some View {
        NavigationView {
            NameScene(name: $name)
        }
    }
}

struct NameScene: View {
    @Binding var name: Name
    
    var body: some View {
        Form {
            NavigationLink {
                FirstNameScene(firstName: $name.first)
            } label: {
                Text("First name")
            }
            .isDetailLink(false) // the fix
            TextField("Last name", text: $name.last)
        }
        .navigationTitle("Name Scene")
    }
}

struct FirstNameScene: View {
    @Binding var firstName: FirstName

    var body: some View {
        Form {
            TextField("First name", text: $firstName.name)
            NavigationLink {
                LocationScene(location: $firstName.origin)
            } label: {
                Text("Origin")
            }
        }
        .navigationTitle("First Name Scene")
    }
}

struct LocationScene: View {
    @Binding var location: Location
    
    var body: some View {
        Form {
            TextField("Country", text: $location.country)
            TextField("City", text: $location.city)
        }
        .navigationTitle("Location Scene")
    }
}
1 Like
3

I was about to check out your fix but I ran this project again today and I couldn't reproduce the bug. I don't know what happened maybe something received an update but my problem seems to have fixed itself... :crossed_fingers:

Thank you for your response tho. :heart: