SwiftUI -两个导航栏

import SwiftUI

struct ContentView: View {
    var body: some View {
        ZStack {
            NavigationView {
                VStack {
                    Text("Main Content")
                        .padding()
                    NavigationLink(destination: SecondView()) {
                        Text("Go to Second View")
                    }
                }
                .navigationBarTitle("Main View")
            }
            
            NavigationView {
                Text("Secondary Navigation Bar")
                    .frame(maxWidth: .infinity, alignment: .leading)
                    .padding()
                .background(Color.gray.opacity(0.2))
                .edgesIgnoringSafeArea(.top)
            }
        }
    }
}

struct SecondView: View {
    var body: some View {
        Text("Second View")
            .navigationBarTitle("Second View")
    }
}

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

import SwiftUI

struct ContentView: View {
    var body: some View {
        NavigationView {
            VStack {
                Text("Main Content")
                    .padding()
                NavigationLink(destination: SecondView()) {
                    Text("Go to Second View")
                }
            }
            .navigationBarTitle("Main View")
            .background(NavigationConfigurator { nc in
                nc.navigationBar.items(inserting: CustomNavigationBarItem()) { }
            })
        }
    }
}

struct SecondView: View {
    var body: some View {
        Text("Second View")
            .navigationBarTitle("Second View")
    }
}

struct CustomNavigationBarItem: ToolbarItem {
    var body: some ToolbarItemContent {
        ToolbarItem(placement: .navigationBarTrailing) {
            Text("Secondary Nav")
                .foregroundColor(.white)
                .padding(.horizontal, 10)
                .background(Color.blue)
                .cornerRadius(5)
        }
    }
}

struct NavigationConfigurator: UIViewControllerRepresentable {
    var configure: (UINavigationController) -> Void = { _ in }

    func makeUIViewController(context: UIViewControllerRepresentableContext<NavigationConfigurator>) -> UIViewController {
        UIViewController()
    }

    func updateUIViewController(_ uiViewController: UIViewController, context: UIViewControllerRepresentableContext<NavigationConfigurator>) {
        if let nc = uiViewController.navigationController {
            self.configure(nc)
        }
    }
}

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