如何在SwiftUI中的IF语句中导航视图

import SwiftUI

struct ContentView: View {
    @State private var isLoggedIn = false // 假设这是一个表示用户是否登录的状态

    var body: some View {
        VStack {
            if isLoggedIn {
                // 如果用户已登录，显示欢迎视图
                NavigationLink(
                    destination: WelcomeView(),
                    label: { Text("Welcome Back!") }
                )
            } else {
                // 如果用户未登录，显示登录视图
                NavigationLink(
                    destination: LoginView(),
                    label: { Text("Login") }
                )
            }
        }
        .navigationTitle("My App")
    }
}

struct WelcomeView: View {
    var body: some View {
        Text("Welcome to your account!")
            .navigationTitle("Welcome")
    }
}

struct LoginView: View {
    var body: some View {
        Text("Please log in.")
            .navigationTitle("Login")
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView(isLoggedIn: .constant(true)) // 用于预览已登录状态
    }
}