我的 swift iOS 应用程序总是在 MainViewController 中启动 - 最初无法在 SceneDeletage 中导航到 LoginViewController

Question

正如我在标题中所说，我无法导航到登录ViewController。我给你看我的代码：

scenedelegate.swift

[...]
    class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?


    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
        // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
        // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).
        guard let windowScene = (scene as? UIWindowScene) else { return }


                self.window = UIWindow(windowScene: windowScene)
                //self.window =  UIWindow(frame: UIScreen.main.bounds)

                let storyboard = UIStoryboard(name: "Main", bundle: nil)
                guard let rootVC = storyboard.instantiateViewController(identifier: "LoginViewController") as? ViewController else {
                    print("ViewController not found")
                    return
                }
                let rootNC = UINavigationController(rootViewController: rootVC)
                self.window?.rootViewController = rootNC
                self.window?.makeKeyAndVisible()
    }
[...]

在我的登录名中ViewController 我只有文本“FALSE”。在 MainViewController 我有文本“TRUE” 当我尝试导航到 MainViewController（带箭头）时，它有效，但是当我尝试导航到 LoginViewController 时，我在控制台中输出：ViewController not found

故事板：

StoryboardsID 很好，因为我没有任何例外：

主要ViewController

登录ViewController

如何解决并导航到登录ViewController？

Answer 1

guard 子句 returns nil 因为您正在将具有 class LoginViewController 的 LoginVC 转换为 ViewController - class 的 mainVC.

将guard let改成这个

guard let rootVC = storyboard.instantiateViewController(withIdentifier: "LoginViewController") as? LoginViewController else {
                print("ViewController not found")
                return
}

Answer 2

你也能告诉我怎么让它更好看吗？我只想在里面处理，不是一个外面一个里面。

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
        // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
        // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).
        guard let windowScene = (scene as? UIWindowScene) else { return }
        self.window = UIWindow(windowScene: windowScene)

        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        var rootVC = storyboard.instantiateViewController(withIdentifier: "MainViewController")
        
        if (false) {
            rootVC = storyboard.instantiateViewController(withIdentifier: "LoginViewController")
        }
        
        let rootNC = UINavigationController(rootViewController: rootVC)
        self.window?.rootViewController = rootNC
        self.window?.makeKeyAndVisible()
    }

我的 swift iOS 应用程序总是在 MainViewController 中启动 - 最初无法在 SceneDeletage 中导航到 LoginViewController

My swift iOS app always launching in MainViewController - can't navigate initially in SceneDeletage to LoginViewController

ios

swift

viewcontroller

swift5