1.在AppDelegate.swift里添加@available(iOS 13.0, *),和var window: UIWindow?
@UIApplicationMain @available(iOS 13.0, *) class AppDelegate: UIResponder, UIApplicationDelegate { var window: UIWindow? func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool { // Override point for customization after application launch. return true }
2.在SceneDelegate.swift添加@available(iOS 13.0, *), var window: UIWindow?
import UIKit @available(iOS 13.0, *) 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 _ = (scene as? UIWindowScene) else { return } }