情节提要删除后黑屏

Question

我删除了故事板和主界面，并从信息plist中删除了黑屏，并显示以下代码

  - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    UIWindow * window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen]bounds] ];
    UIViewController *UVC=[[UIViewController alloc] init];
    UVC.view.bounds=[[UIScreen mainScreen]bounds] ;
    UVC.title=@"AAA";
    UVC.view.backgroundColor=[UIColor greenColor];
    window.rootViewController = UVC;
    [window makeKeyAndVisible];
    application.delegate.window=window;
    return YES;
}

其ios 13问题。