Iphone用UINavigationController实现在两个页之间导航（上）(2)

    
    tabBarController = [[UITabBarController alloc] init];//初始化标签栏控制器 
    MeiShiTianDi *viewController =[[MeiShiTianDi alloc] init];//初始化控制器 
    viewController.title=@"美食天地"; 
    navController = [[UINavigationController alloc] init];//初始化导航控制器 
    //加入标签栏控制器的控制器数量矩阵 
    tabBarController.viewControllers = 
    [NSArray arrayWithObjects:navController, viewController,nil]; 
    
    [viewController release]; 
    //定义名称为“所有城市”的返回按钮。该按钮无需target和action 
//因为系统已经实现了返回功能。Style是显示风格 
    UIBarButtonItem *backButton = 
       [[UIBarButtonItem alloc] initWithTitle:@"所有城市" 
           style:UIBarButtonItemStyleBordered 
           target:nil action:nil]; 
    //设置启动应用时第一个要显示的视图控制器，这里是cityViewContrl 
    cityViewController *cityViewContrl = [[cityViewController alloc] init]; 
    cityViewContrl.title = @"旅游指南";//设置第一个视图控制器的标题 
    //设置返回按钮 
    cityViewContrl.navigationItem.backBarButtonItem= backButton; 
    [backButton release]; 
    //把第一个视图控制器推push到堆栈中 
    [navController pushViewController:cityViewContrl animated:NO]; 
    //这里假定是导航栏的第一个视图，所以animated:NO不要动画化。 
    [cityViewContrl release]; 
    //把导航（标签栏）控制器放到Window下 
    //[window addSubview:navController.view]; 
    [window addSubview:tabBarController.view]; 
    
    // Override point for customization after application launch. 
    [window makeKeyAndVisible]; 
    return YES; 
} 
- (void)applicationWillResignActive:(UIApplication *)application { 
    
} 
- (void)applicationDidEnterBackground:(UIApplication *)application { 
    
} 
- (void)applicationWillEnterForeground:(UIApplication *)application { 
    
} 
- (void)applicationDidBecomeActive:(UIApplication *)application { 
    
} 
- (void)applicationWillTerminate:(UIApplication *)application {