一、Main.StoryBoard的使用

1、使用Main.StoryBoard(Default)

无需特殊处理，Xcode 11及其以上版本，默认生成用’Main.StoryBoard’模板

2、不使用Main.StoryBoard

• a、在info.plist文件中找到Storyboard Name键值对，将其移除
  
• b、在TARGETS->info下找到Main storyboard file base name键值对，将其移除
  
• c、删除Main.storyboard
• d、在侧边栏TARGETS->General下，找到Deployment Info项，在Status Bar Style选项中,勾选Supports multiple windows选项

二、SceneDelegate的使用

1、项目中使用SceneDelegate

• a、打开SceneDelegate.m文件，在scenewillConnectToSession代理方法中，创建window窗口，初始化rootViewController
  -(void)scene:(UIScene*)scenewillConnectToSession:(UISceneSession*)sessionoptions:(UISceneConnectionOptions*)connectionOptions {
  UIWindowScenewindowScene = (UIWindowScene)scene;
  self.window= [[UIWindowalloc]initWithWindowScene:windowScene];
  self.window.frame = windowScene.coordinateSpace.bounds;
  self.window.rootViewController = ViewController.new;
  [self.window makeKeyAndVisible];
  }

2、 项目中不使用SceneDelegate

• a、在info.plist文件中找到Application Scene Manifest键值对，将其移除
  
• b、在AppDelegate.m文件，移除UISceneSession lifecycle代理方法， 即application configurationForConnectingSceneSession 和applicationdidDiscardSceneSessions两个方法
  #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[[UISceneConfigurationalloc]initWithName:@"Default Configuration"sessionRole:connectingSceneSession.role];
  }
  -(void)application:(UIApplication)applicationdidDiscardSceneSessions:(NSSet *)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.
  }
• c、AppDelegate.h文件，新增window属性
  @property (strong, nonatomic) UIWindow *window;
• d、AppDelegate.m文件中，在applicationdidFinishLaunchingWithOptions代理方法中，创建window窗口，初始化rootViewController
  -(BOOL)application:(UIApplication*)applicationdidFinishLaunchingWithOptions:(NSDictionary*)launchOptions {
  // Override point for customization after application launch.
  self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
  self.window.backgroundColor = UIColor.whiteColor;
  self.window.rootViewController = [[UINavigationController alloc]initWithRootViewController:[[ViewController alloc]init]];
  [self.window makeKeyAndVisible];
  return YES;
  }