如下例子我先拖入一个Storyboard，里面放置一个UINavigationController和一个HomeViewController
AppDelegate.m
UIStoryboard *homeSB = [UIStoryboard storyboardWithName:@"Home" bundle:[NSBundle mainBundle]];
HomeViewController *homeVC = [homeSB instantiateViewControllerWithIdentifier:@"HomeViewController"];
//UINavigationController *homeNav = [[UINavigationController alloc] initWithRootViewController:[homeSB instantiateViewControllerWithIdentifier:@"HomeViewController"]];
self.window.rootViewController = homeVC;
