ios – Goal C programmatically View ViewController However Black Display screen

When debugging, viewDidLoad of LoginViewController known as, however the display screen is black display screen. I actually do not know why..

@interface AppDelegate ()

@property (nonatomic, robust) AppCoordinator *appCoordinator;

@finish

@implementation AppDelegate


- (BOOL)software:(UIApplication *)software didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc] initWithFrame: UIScreen.mainScreen.bounds];
    UIStoryboard *sb = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
    LoginViewController *vc = [sb instantiateViewControllerWithIdentifier:@"LoginView"];
    
    //UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController: vc];
    self.window.rootViewController = vc;
    [self.window makeKeyAndVisible];
    
    return YES;
}