Ios 没有情节提要的应用程序启动-UIViewController仍然不可见

读后

我已经执行了以下步骤

从项目中删除

Main.storyboard

和

LaunchScreen.storyboard

从部署信息下的主界面中删除主界面

从

Info.plist

下面是上述步骤的一些屏幕截图

在

AppDelegate.swift

中，我做了以下修改

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        
        window = UIWindow(frame: UIScreen.main.bounds)
        let viewController = ViewController()
        viewController.view.backgroundColor = UIColor.red
        window!.rootViewController = viewController
        window!.makeKeyAndVisible()
        
        print("application executed")
        
        return true
    }
}

当我启动模拟器时，控制台上会打印“已执行的应用程序”

我希望在应用程序启动后看到全屏红色。然而，我只能看到整个黑屏

---

我可以知道我还遗漏了哪些步骤吗？

您有场景生命周期，所以应该在

SceneDelegate

中创建窗口

下面是AppDelegate的

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        return true
    }

    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }
}

现在是
SceneDelegate


class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?


    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {

        if let windowScene = scene as? UIWindowScene {
            let viewController = ViewController()
            viewController.view.backgroundColor = UIColor.red

            let window = UIWindow(windowScene: windowScene)
            window.rootViewController = viewController
            self.window = window
            window.makeKeyAndVisible()
        }
    }
}

您有场景生命周期，所以应该在
SceneDelegate
中创建窗口

下面是AppDelegate的

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        return true
    }

    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }
}

现在是
SceneDelegate


class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?


    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {

        if let windowScene = scene as? UIWindowScene {
            let viewController = ViewController()
            viewController.view.backgroundColor = UIColor.red

            let window = UIWindow(windowScene: windowScene)
            window.rootViewController = viewController
            self.window = window
            window.makeKeyAndVisible()
        }
    }
}