UINavigationController 与 UITabBarController

// index start from 1.
UITabBarItem *newsItem = [[UITabBarItem alloc] initWithTabBarSystemItem:UITabBarSystemItemFavorites tag:1];
//UITabBarItem *homeItem = [[UITabBarItem alloc] initWithTitle:@"首页" image:[UIImage imageNamed: @""] tag:1];
NewsViewController *newsController = [[NewsViewController alloc] init];
newsController.tabBarItem = newsItem;
[newsItem release];

UINavigationController *newsNav = [[UINavigationController alloc] initWithRootViewController:newsController];
[newsController release];

// repeat other here

NSArray *viewControllers = @[newsNav];
[newsNav release];

UITabBarController *tabController = [[UITabBarController alloc]init];
// tabController.viewControllers = @[newsNav];
[tabController setViewControllers:viewControllers animated:YES];

self.window.rootViewController = tabController;