问如何在没有故事板的Xcode中创建空应用程序

EN

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
    self.window?.backgroundColor = UIColor.whiteColor()
    self.window?.makeKeyAndVisible()
    return true
}

//AppDelegate.h


@property (strong, nonatomic) UIViewController *viewController;
@property (strong, nonatomic) UINavigationController *nav;

//AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {`enter code here`
    // Override point for customization after application launch.

    CGRect screenBounds = [[UIScreen mainScreen] bounds];

    UIWindow *window = [[UIWindow alloc] initWithFrame:screenBounds];


    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];



    self.viewController = [[UIViewController alloc] initWithNibName:@"ViewController" bundle:nil];

    self.nav = [[UINavigationController alloc] initWithRootViewController:self.viewController];

    [window setRootViewController:  self.nav];

    [window makeKeyAndVisible];

    [self setWindow:window];

    return YES;
}