iOS 13 SceneDelegate適配(Xcode 11,適配ios13以下系統)

在Xcode11上新建一個iOS的帶storyboard的項目

最低適配的系統改到iOS13以下後

解決方案一：刪除SceneDelegate,還原到iOS13以前的版本(本人親測可行)

1.給AppDelegate添加window屬性
2.註釋掉AppDelegate中UISceneSession Lifecycle下面的兩個代理方法

3.刪除Info.plist中的Application Scene Manifest字段

4.刪掉SceneDelegate.swift文件

5.在AppDelegate中把之前的幾個代理方法寫回來

AppDelegate中的代碼

//
//  AppDelegate.swift
//  MySceneDelegate
//
//  Created by macvivi on 2020/6/9.
//  Copyright © 2020 macvivi. All rights reserved.
//

import UIKit

@UIApplicationMain
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
    }
    
    // MARK: UISceneSession Lifecycle
    
    //    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)
    //    }
    //
    //    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.
    //    }
    
    
    func applicationWillResignActive(_ application: UIApplication) {
        // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
        // Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
    }
    
    func applicationDidEnterBackground(_ application: UIApplication) {
        
        // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
        // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
    }
    
    func applicationWillEnterForeground(_ application: UIApplication) {
        // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
    }
    
    func applicationDidBecomeActive(_ application: UIApplication) {
        // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
    }
    
    func applicationWillTerminate(_ application: UIApplication) {
        
        
        // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    }
    
    
    
}

方案二：iOS13以上系統使用SceneDelegate，iOS13以下系統不使用SceneDelegate（本人還未測試）

參考博客：
Xcode11新變化：SceneDelegate

其他參考博客：

iOS13 Scene Delegate詳解

iOS 13 SceneDelegate適配