1 ViewController *vc = [[ViewController alloc] init];

1 ViewController *vc = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];

1 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {2     // 手動添加window到screen3     self.window = [[UIWindow alloc] init];4     self.window.frame = [[UIScreen mainScreen] bounds];5     self.window.backgroundColor = [UIColor grayColor];6     [self.window makeKeyAndVisible];7     return YES;8 }

1     // 2.取得stroyboard2     UIStoryboard *sb = [UIStoryboard storyboardWithName:@"mysb" bundle:nil];

1     // 3.1直接使用InitialViewController2     self.window.rootViewController = [sb instantiateInitialViewController];

1     // 4.使用ID取得controller, 設置rootViewController2     self.window.rootViewController = [sb instantiateViewControllerWithIdentifier:@"vc2"];

 1 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { 2     // 1.手動添加window到screen 3     self.window = [[UIWindow alloc] init]; 4     self.window.frame = [[UIScreen mainScreen] bounds]; 5     self.window.backgroundColor = [UIColor grayColor]; 6     [self.window makeKeyAndVisible]; 7     8     // 2.取得stroyboard 9     UIStoryboard *sb = [UIStoryboard storyboardWithName:@"mysb" bundle:nil];10    11     // 3.取出storyboar中的controller12     // 3.1直接使用InitialViewController13     ViewController *controller = [sb instantiateInitialViewController];14    15     // 3.2使用ID16     ViewController2 *controller2 = [sb instantiateViewControllerWithIdentifier:@"vc2"];17    18     // 4.設置rootViewController19     self.window.rootViewController = controller2;20    21     return YES;22 }

 1 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { 2     // 1.手動添加window到screen 3     self.window = [[UIWindow alloc] init]; 4     self.window.frame = [[UIScreen mainScreen] bounds]; 5     self.window.backgroundColor = [UIColor grayColor]; 6     [self.window makeKeyAndVisible]; 7   8     // 從xib加載控制器, 設置rootViewController 9     self.window.rootViewController = [[XibViewController alloc] initWithNibName:@"myx" bundle:nil];10     11     return YES;12 }

 1 // 加載view，這是延遲加載，當需要使用view而view是空的時候調用 2 - (void)loadView { 3     NSLog(@"loadView..."); 4     self.view = [[UIView alloc] init]; 5     self.view.frame = [[UIScreen mainScreen] bounds]; 6     UILabel *label = [[UILabel alloc] init]; 7     label.frame = CGRectMake(40, 40, 100, 100); 8     label.text = @"loadView"; 9     [self.view addSubview:label];10 }

 1 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { 2     // 配置window 3     self.window = [[UIWindow alloc] init]; 4     self.window.frame = [[UIScreen mainScreen] bounds]; 5     self.window.backgroundColor = [UIColor grayColor]; 6     7     // 配置storyboard中的controller為rootViewController 8     self.window.rootViewController = [[UIStoryboard storyboardWithName:@"test" bundle:nil] instantiateInitialViewController]; 9   10      // 配置xib中的controller為rootViewController，主要要使用帶有loadView的controller11 //    self.window.rootViewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];12    13     // 顯示window14     [self.window makeKeyAndVisible];15     return YES;16 }17  

1      // 配置xib中的controller為rootViewController，主要要使用帶有loadView的controller2     self.window.rootViewController = [[ViewController alloc] initWithNibName:@"ViewController" bundle:nil];