通过代码手动加载storyboard

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

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

    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];

    UIViewController *viewController = [storyboard instantiateInitialViewController];

    self.window.rootViewController = viewController;

    [self.window makeKeyAndVisible];

    return YES;
}