加载storyboard,并设置根控制器

// 加载storyboard    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];        // 加载箭头指向的控制器    UIViewController *vc = [storyboard instantiateInitialViewController];        // 设置窗口的根控制器    self.window.rootViewController = vc;