viewを囲って使

struct A: View {
    @State var isActive = false
    @State var number = Int.random(in: 1..<10).description

    var body: some View {
        NavigationView {
            Container {
                VStack {
                    Button(action: {
                        self.isActive.toggle()
                    }) {
                        Text("移動A\(number)")
                    }
                    NavigationLink(destination: B(),isActive: $isActive) {
                        EmptyView()
                    }
                }
            }
        }.navigationViewStyle(StackNavigationViewStyle())

    }
}


struct Container <Content : View> : View {
    
    var content : Content
    @State var isLogin = false

    init(@ViewBuilder content: () -> Content) {
        self.content = content()
    }
    
    var body: some View {
        ZStack {
            Color.yellow.edgesIgnoringSafeArea(.all)
            VStack {
                VStack() {
                    if isLogin {
                        content
                    } else {
                        Text("ログインへ")
                    }
                }
            }
        }.onAppear() {
            isLogin = false
        }
    }
}