xcode11建立新項目時，黑屏了，不顯示View

在興沖沖更新了Xcode11，并建立了項目之後，且發現真機和模拟器都黑屏了，怎麼都不顯示View了。

然後項目中比之前莫名其妙的多出來了兩個檔案:

APPdelegate.m中也多了兩段不明是以的代碼：

#pragma mark - UISceneSession lifecycle
- (UISceneConfiguration *)application:(UIApplication *)application configurationForConnectingSceneSession:(UISceneSession *)connectingSceneSession options:(UISceneConnectionOptions *)options {
    // Called when a new scene session is being created.
    // Use this method to select a configuration to create the new scene with.
    return [[UISceneConfiguration alloc] initWithName:@"Default Configuration" sessionRole:connectingSceneSession.role];
}
- (void)application:(UIApplication *)application didDiscardSceneSessions:(NSSet<UISceneSession *> *)sceneSessions {
    // 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.
}
           

經查詢資料得知，IOS13之後，生命周期時間就開始由

UISceneDelegate

接管了，一時間真的是措手不及啊，不過适應之前可以先通過以下辦法恢複到原來的項目結構：

1. 删除info.plist中的

   Application Scene Manifest

   

2. 删除項目中的Scenedelegate.h和Scenedelegate.m
3. 删除掉APPdelegate.m中的

   #pragma mark - UISceneSession lifecycle

   代碼
4. 在APPdelegate.h中添加

   @property (strong, nonatomic) UIWindow * window;

   屬性

然後，老朋友就還是熟悉的項目，熟悉的味道了。