即使添加了SceneDelegate并更新了Info.plist之后，Xcode 11黑屏上的iOS13

我目前正在使用Xcode 11，Target iOS 13.0进入黑屏状态（该应用程序在所有低于iOS 12.1至12.4的版本中均能正常工作），我想让我的应用程序可同时用于12.1以上的iOS用户和13.0的用户，尽管将以下SceneDelegate添加到我现有的项目中，

添加App Manifest文件

import UIKit
    import SwiftUI

    @available(iOS 13.0, *)
    class SceneDelegate: UIResponder, UIWindowSceneDelegate {

        var window: UIWindow?

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

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

            let user  = UserDefaults.standard.object(forKey: "defaultsuserid")

            let userSelfIdent  = UserDefaults.standard.object(forKey: "userinitialident")

            if let windowScene = scene as? UIWindowScene {

                let internalWindow = UIWindow(windowScene: windowScene)

                if (user != nil && userSelfIdent != nil){
                     let mainstoryboard:UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
                     let newViewcontroller:UIViewController = mainstoryboard.instantiateViewController(withIdentifier: "swrevealviewcontroller") as! SWRevealViewController
                        internalWindow.rootViewController = newViewcontroller
                        self.window = internalWindow
                        internalWindow.makeKeyAndVisible()
                }else {

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

以下是我的AppDelegate，它将首先被调用并执行该didFinishLaunchWithOptions方法。我想知道如何仅在Target ios小于13.0时调用此方法，并在13.0之后调用SceneDelegate方法初始化rootViewController？

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    @available(iOS 13.0, *)
    func application(_ application: UIApplication,
                     configurationForConnecting connectingSceneSession: UISceneSession,
                     options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }

    @available(iOS 13.0, *)
    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {

    }



    @available(iOS 13.0, *)
    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {

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

        if (user != nil && userSelfIdent != nil){

              let mainstoryboard:UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
              let newViewcontroller:UIViewController = mainstoryboard.instantiateViewController(withIdentifier: "swrevealviewcontroller") as! SWRevealViewController
                self.window?.rootViewController = newViewcontroller
        }
    }

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.

        Thread.sleep(forTimeInterval: 3.0)

        UINavigationBar.appearance().barTintColor = UIColor(red:0.08, green:0.23, blue:0.62, alpha:1.0)

        if (user != nil && userSelfIdent != nil){

              let mainstoryboard:UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
              let newViewcontroller:UIViewController = mainstoryboard.instantiateViewController(withIdentifier: "swrevealviewcontroller") as! SWRevealViewController
                self.window?.rootViewController = newViewcontroller
        }

        return true
    }

    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {

        let defaultUserID = UserDefaults.standard.string(forKey: "defaultUserID")


    }

    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {

        switch (application.applicationState) {
        case UIApplicationState.active:
            do something

        case UIApplicationState.background, UIApplicationState.inactive:

            let mainstoryboard:UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
            let newViewcontroller = mainstoryboard.instantiateViewController(withIdentifier: "swrevealviewcontroller") as! SWRevealViewController
            self.window?.rootViewController = newViewcontroller            
        }
    }

您这里有几个问题。阅读与应用程序生命周期相关的文档非常重要，该文档阐明了iOS 13下的内容和iOS 12下的内容。

您可能还需要查看支持iOS 12和13的我的Single View App模板。

查看您的代码，这是问题的摘要：

AppDelegate：

• 如果应用程序在iOS 12或更早版本下运行，则仅应设置主窗口和根视图控制器。您需要在运行时检查。
• 该func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions)方法不应在应用程序委托中。
• 没有直接关系，但从不休眠应用程序启动。删除Thread.sleep(forTimeInterval: 3.0)线。用户想要使用您的应用程序，而不是盯着启动屏幕停留超过必要的时间。并且在应用启动时阻止主线程可能导致您的应用被杀死。

SceneDelegate：

• 这通常很好，但是没有理由使用该guard let _ = (scene as? UIWindowScene) else { return }行，尤其是因为它位于if let已经进行了该检查的内部。
• 您似乎没有使用SwiftUI，因此请删除该导入。

我将更新您的应用程序委托，使其更像这样：

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

    func application(_ application: UIApplication, willFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? = nil) -> Bool {
        UINavigationBar.appearance().barTintColor = UIColor(red:0.08, green:0.23, blue:0.62, alpha:1.0)

        if #available(iOS 13.0, *) {
            // In iOS 13 setup is done in SceneDelegate
        } else {
            let window = UIWindow(frame: UIScreen.main.bounds)
            self.window = window

            if (user != nil && userSelfIdent != nil){
                let mainstoryboard:UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
                let newViewcontroller:UIViewController = mainstoryboard.instantiateViewController(withIdentifier: "swrevealviewcontroller") as! SWRevealViewController
                window.rootViewController = newViewcontroller
            }
        }

        return true
    }

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        if #available(iOS 13.0, *) {
            // In iOS 13 setup is done in SceneDelegate
        } else {
            self.window?.makeKeyAndVisible()
        }

        return true
    }

    func applicationWillResignActive(_ application: UIApplication) {
        // Not called under iOS 13 - See SceneDelegate sceneWillResignActive
    }

    func applicationDidEnterBackground(_ application: UIApplication) {
        // Not called under iOS 13 - See SceneDelegate sceneDidEnterBackground
    }

    func applicationWillEnterForeground(_ application: UIApplication) {
        // Not called under iOS 13 - See SceneDelegate sceneWillEnterForeground
    }

    func applicationDidBecomeActive(_ application: UIApplication) {
        // Not called under iOS 13 - See SceneDelegate sceneDidBecomeActive
    }

    // MARK: UISceneSession Lifecycle

    @available(iOS 13.0, *)
    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        // Called when a new scene session is being created.
        // Use this method to select a configuration to create the new scene with.
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }

    @available(iOS 13.0, *)
    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
        // Called when the user discards a scene session.
        // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
        // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
    }
}

您的场景代表可能像：

@available(iOS 13.0, *)
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
    var window: UIWindow?

    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        guard let windowScene = (scene as? UIWindowScene) else { return }

        let window = UIWindow(windowScene: windowScene)
        self.window = window

        if (user != nil && userSelfIdent != nil){
            let mainstoryboard:UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
            let newViewcontroller:UIViewController = mainstoryboard.instantiateViewController(withIdentifier: "swrevealviewcontroller") as! SWRevealViewController
            window.rootViewController = newViewcontroller
            window.makeKeyAndVisible()
        }
    }

    func sceneDidDisconnect(_ scene: UIScene) {
        // Called as the scene is being released by the system.
    }

    func sceneDidBecomeActive(_ scene: UIScene) {
        // Not called under iOS 12 - See AppDelegate applicationDidBecomeActive
    }

    func sceneWillResignActive(_ scene: UIScene) {
        // Not called under iOS 12 - See AppDelegate applicationWillResignActive
    }

    func sceneWillEnterForeground(_ scene: UIScene) {
        // Not called under iOS 12 - See AppDelegate applicationWillEnterForeground
    }

    func sceneDidEnterBackground(_ scene: UIScene) {
        // Not called under iOS 12 - See AppDelegate applicationDidEnterBackground
    }
}

因此，升级到iOS 13及更低版本的步骤

1）将部署目标更改为iOS 12。

2）将AppDelegate的方法替换为iOS 12开发应具有的方法。还要添加以下内容：

   var window: UIWindow?

3）删除SceneDelegate。

4）在info.plist中删除Application Scene Manifest。

它可以在iOS 13和更低的iOS版本上运行

我陷入了这个问题，最后我解决了从情节提要中删除searchDisplayController引用的问题。

<searchDisplayController id="pWz-So-g6H">
                    <connections>
                        <outlet property="delegate" destination="Yci-sd-Mof" id="fjs-ah-jLs"/>
                        <outlet property="searchContentsController" destination="Yci-sd-Mof" id="gQN-1r-gti"/>
                        <outlet property="searchResultsDataSource" destination="Yci-sd-Mof" id="2Jf-lh-Ute"/>
                        <outlet property="searchResultsDelegate" destination="Yci-sd-Mof" id="Hap-SA-f02"/>
                    </connections>
                </searchDisplayController>

当我遇到类似的问题时，这是由于使用Xcode 11.0生成的Single-App模板与使用Xcode 11.2构建的应用程序所需的模板不兼容。

因此，我刚刚使用Xcode 11.2创建了一个新的Single-Page-App，并将生成的SceneDelegate复制到了使用Xcode 11.0创建的旧项目中。

之后，黑屏消失了，我的界面再次可见。

轻松享受这些步骤

1-）删除场景委托文件

2-）将以下代码添加到AppDelegate.swift

    class AppDelegate: UIResponder, UIApplicationDelegate {

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

3-）从.plist文件中删除Application Scene Manifest行