NavigationStack with iOS 16  - Back to Root View

ContentView.swift

import SwiftUI

struct ContentView : View {
    
    @EnvironmentObject var router: Router
    
    var body: some View {
        
        NavigationStack(path: $router.path) {
          
            VStack {
                // other elements ...
                Text("Home")
                    .padding()
                    
                Button("go to FormView"){
                    router.gotoFormView()
                }
            }
            .navigationDestination(for: Views.self){ destination in
                ViewFactory.viewForDestination(destination)
            }
        }
        
    }
}

FormView.swift

import SwiftUI

struct FormView: View {
    
    @EnvironmentObject var router: Router

    var body: some View {

        NavigationStack(path: $router.path) {
            
            VStack {
                // other elements ...
                Text("Form")
                    .padding()
                    
                Button("go to PreviewView"){
                    router.gotoPreviewView()
                }
            }
            .navigationDestination(for: Views.self){ destination in
                ViewFactory.viewForDestination(destination)
            }
        }
        
    }
}

Models.swift

import SwiftUI

enum Views: Hashable {
    
    case HomeView
    case FormView
    case PreviewView
    
}


class Router: ObservableObject {
    
    @Published var path = NavigationPath()
    
    func clear() {
        path = .init()
    }
    
    func gotoFormView() {
        path.append(Views.FormView)
    }
    
    func gotoPreviewView() {
        path.append(Views.PreviewView)
    }
    
}

// class ViewFactory {
//     
//     static func viewForDestination(_ destination: Views) -> AnyView {
//         
//         switch destination {
//             
//         case .HomeView:
//            return AnyView(EmptyView()) // since we dont need to make destination directly to HomeView
//             
//         case .FormView:
//             return AnyView(FormView())
//             
//         case .PreviewView:
//             return AnyView(PreviewView())
//         }
//     }
// }


// Update: 2023.03.16
// just for namespace, modify the type from `class` to `enum` without `return AnyView()`
enum ViewFactory {
    
    @ViewBuilder
    static func viewForDestination(_ destination: Views) -> some View {
        
        switch destination {
            
        case .HomeView:
           EmptyView() // since we dont need to make destination directly to HomeView
            
        case .FormView:
            FormView()
            
        case .PreviewView:
            PreviewView()
        }
    }
}

PreviewView.swift

import SwiftUI

struct PreviewView: View {
    
    @EnvironmentObject var router: Router
    
    var body: some View {
      
        NavigationStack(path: $router.path) {
          
            VStack {
                // other elements ...
                Text("Preview")
                    .padding()
                    
                Button("back to HomeView"){
                    router.clear()
                }
            }
            .navigationDestination(for: Views.self){ destination in
                ViewFactory.viewForDestination(destination)
            }
        }

    }
}

ProjectApp.swift

import SwiftUI

@main
struct ProjectApp: App {
    
    @ObservedObject var router = Router()
    
    var body: some Scene {
        WindowGroup {
            
            NavigationStack(path: $router.path){
                ContentView()
                    .navigationDestination(for: Views.self){ destination in
                        ViewFactory.viewForDestination(destination)
                    }
            }
            .environmentObject(router)
           
        }
    }
}

If we want to inject some data to the corresponding view, how can we achieve that? Suppose I have a variable in PreviewView and I have to initialise it in the init of PreviewView, how can we do that?

Hello nischalhariqburst,

Thanks for your reply.
Could you give me more information about what kind of data you wish to init for the PreviewView ?

As the time I wrote the article and implemented, I made a Config.swift file for maintain config class and other stuffs with another @EnvironmentObject.

//  PreviewView.swift

struct PreviewView: View {
    
    @EnvironmentObject var router: Router
    @EnvironmentObject var config: Config

    /* .... */
}

And I also put some variable with private var attributes, ex:

    /* ... */
    @EnvironmentObject var config: Config

    private var isChinese: Bool {
        return (config.language == Language.zh_TW) ? true : false
    }
    
    private var preview_string: String {
        return isChinese ? "預覽" : "Preview"
    }
    private var confirm_string: String {
        return isChinese ? "確認" : "Confirm"
    }
    
    private var data: UserData {
        return config.response!.userData
    }

    var body: some View {

        /* ... */

    }

And here is some references FYI:

• https://sarunw.com/posts/state-variable-initialization/
• https://forums.developer.apple.com/forums/thread/649438

Please feel free to contact me if you have further questions.