SwiftUI-New-NavigationAPIs.swift

import SwiftUI

final class Router: ObservableObject {
    @Published var path = NavigationPath()
}

struct ContentView: View {
    
    @EnvironmentObject var router: Router
    
    var body: some View {
        NavigationStack(path: $router.path) {
            RowListsView()
            .navigationDestination(for: Int.self) { i in
                RowListsView()
            }
        }
        .environmentObject(router)
    }
}

struct RowListsView : View{
    
    @EnvironmentObject var router: Router
    
    var body: some View{
        
        Form{
            List(1..<5) { i in
                NavigationLink(value: i) {
                    Text("\(i)")
                }
            }
            Section{
                
                if router.path.count > 0
                {
                    Button("Screen count \(router.path.count)"){
                        print("")
                    }
                    
                    Button("Pop to root", role: .destructive){
                        router.path = .init()
                    }
                    
                    Button("Jump back two screens", role: .none){
                        
                        if router.path.count >= 2{
                            router.path.removeLast(2)
                        }
                        else if router.path.count >= 1{
                            router.path.removeLast(1)
                        }
                    }
                }
            }
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    
    static let envObject = Router()

    static var previews: some View {
        ContentView()
            .environmentObject(envObject)
        
    }
}

getting this runtime warning

Publishing changes from within view updates is not allowed, this will cause undefined behavior.

on line https://gist.github.com/anupamchugh/eba92fc51dbc5e155adfdc3770d31d99#file-swiftui-new-navigationapis-swift-L43

Hello ,
I just tried this example , but I got there is a crash message
Thread 1: Fatal error: No ObservableObject of type Router found. A View.environmentObject(_:) for Router may be missing as an ancestor of this view.

@AmrAbedal same problem. Did you manage to solved it?

@Piggyback13 Yah , it solved , change line 9 to be
@StateObject var router: Router = Router()

getting this runtime warning

Publishing changes from within view updates is not allowed, this will cause undefined behavior.

on line https://gist.github.com/anupamchugh/eba92fc51dbc5e155adfdc3770d31d99#file-swiftui-new-navigationapis-swift-L43

from my search , some folks , say that this warning is an Xcode bug .

@AmrAbedal thank you man

I had a code snippet as below where I modified the navigationDestination with isPresented argument to control when will the view change, but at the end of the SecondView, the reset button didn't bring the navigationStack to the root view with ContentView, it just do nothing when pressing the reset button.

I have tried wrapping the body within the NavigationStack(path: $router.path), but still not working.

import SwiftUI

final class Router: ObservableObject {
    
    @Published var path = NavigationPath()
    
}

struct ContentView: View {
    
    @StateObject var router: Router = Router()
    
    @State private var showFirstView: Bool = false
    
    var body: some View {
        
        NavigationStack(path: $router.path) {
            
            Button("Start") {
                showFirstView = true
            }
            
            .navigationDestination(isPresented: $showFirstView) {
                FirstView()
            }
            
            .navigationTitle("Home")
        }
        .environmentObject(router)
    }
}


struct FirstView: View {
    
    @EnvironmentObject var router: Router
    @State private var showSecondView: Bool = false
    
    var body: some View {
        
        Button("Go second") {
            showSecondView = true
        }
        
        .navigationDestination(isPresented: $showSecondView){
            SecondView()
        }
    }
    
}

struct SecondView: View {
    
    @EnvironmentObject var router: Router
    
    var body: some View {
        
        Button("reset"){
            router.path = .init()
        }
        
    }
    
}

Appreciate for the help. Thanks !!