如何在appdelegate文件中使用导航控制器和标签栏控制器

我正面临着显示导航控制器和标签栏控制器的问题，根据应用程序启动方法中添加子视图的位置显示一个。

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

// Override point for customization after application launch.
   navigationController.navigationBar.barStyle = UIBarStyleBlackOpaque;
// Add the view controller's view to the window and display.
[self.window addSubview:navigationController.view];
[self.window addSubview:tabBarController.view];

[self.window makeKeyAndVisible];

return YES;
 }