swift - SceneDelegate 中的 Launch 和第一个 ViewController 之间黑屏闪烁

Question

我使用 SceneDelegate.swift 来决定使用此代码显示哪个 ViewController:

guard let windowScene = (scene as? UIWindowScene) else { return }

    if Auth.auth().currentUser != nil {

        AuthenticationService.automaticSignIn(onSuccess: {

            let window = UIWindow(windowScene: windowScene)
            self.window = window
            let mainstoryboard:UIStoryboard = UIStoryboard(name: "Login", bundle: nil)
            let newViewcontroller:UIViewController = mainstoryboard.instantiateViewController(withIdentifier: "TabBarControllerID") as! TabBarController
            window.rootViewController = newViewcontroller
            window.makeKeyAndVisible()

        }, onError: {

            let window = UIWindow(windowScene: windowScene)
            self.window = window
            let mainstoryboard:UIStoryboard = UIStoryboard(name: "Login", bundle: nil)
            let newViewcontroller:UIViewController = mainstoryboard.instantiateViewController(withIdentifier: "LoginViewControllerID") as! LoginViewController
            window.rootViewController = newViewcontroller
            window.makeKeyAndVisible()

        })
    } else {

        let window = UIWindow(windowScene: windowScene)
        self.window = window
        let mainstoryboard:UIStoryboard = UIStoryboard(name: "Login", bundle: nil)
        let newViewcontroller:UIViewController = mainstoryboard.instantiateViewController(withIdentifier: "LoginViewControllerID") as! LoginViewController
        window.rootViewController = newViewcontroller
        window.makeKeyAndVisible()
    }
}

在转换之间，会出现黑屏(在我的 .gif 中大约持续 0.2 秒)，具体取决于加载时间。抱歉质量不好且持续时间短，但您会看到它:

这个黑屏从何而来？

Answer 1

尝试更改此行:-
self.window!.rootViewController = UINavigationController(rootViewController: DashboardVC)
self.window!.makeKeyAndVisible()