加载定义界面

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

{

    // 1.创建窗口

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

    // 2.设置窗口的根控制器

    MyTabBarController *tabBarVC = [[MyTabBarController alloc]init];

    self.window.rootViewController = tabBarVC;

    // 3.显示窗口

    [self.window makeKeyAndVisible];

    return YES;

}