UITabBar中的UITabBarItems在我单击项目后显示，而不是在应用程序启动时

我写的这个应用程序有一个问题。

我正在我的应用程序窗口中设置UITabBar并在视图文件中设置图标。 但是，当我运行应用程序时，第一个图标显示（因为视图已加载，我猜），其他图标在我点击它们之前不会显示。

我是否需要在其他方法中实现self.tabBarItem而不是viewDidLoad ？

在此先感谢大家！

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { tabBar = [[UITabBarController alloc] init]; SubscriptionsController *subscriptionsController = [[SubscriptionsController alloc] init]; FavoritesController *favoritesController = [[FavoritesController alloc] init]; CategoriesController *categoriesController = [[CategoriesController alloc] init]; TagsController *tagsController = [[TagsController alloc] init]; HelpScreenController *helpScreenController = [[HelpScreenController alloc] init]; tabBar.viewControllers = [NSArray arrayWithObjects: subscriptionsController, favoritesController, categoriesController, tagsController, helpScreenController, nil ]; [window addSubview:tabBar.view]; // Override point for customization after application launch. [window makeKeyAndVisible]; return YES; } //The View - (void)viewDidLoad { [super viewDidLoad]; tabIcon = [[UITabBarItem alloc] initWithTitle:@"Abonime" image:[UIImage imageNamed:@"subscr.png"] tag:0]; self.tabBarItem = tabIcon; [tabIcon release]; } 

Answer 1

我认为你应该在视图控制器的指定初始化程序中设置tabBarItem属性（从你的代码判断，它必须是每个控制器的-init ）。 实际上，标签栏控制器非常智能，可以按需加载视图，也就是说，应该在发送viewDidLoad之前设置tabBarItem属性。

此外，您似乎泄漏了所有视图控制器。 要解决此问题，请执行以下操作：

 SubscriptionsController *subscriptionsController = [[[SubscriptionsController alloc] init] autorelease]; 

Answer 2

正确。 图标不会显示，因为视图（除第一个之外，尚未加载）。 并且在您点击视图之前不会加载，因为直到那时才调用viewDidLoad。

删除单个UIViewControllers viewDidLoad中的代码并执行此操作…

 NSArray *controllers = [NSArray arrayWithObjects: [NSDictionary dictionaryWithObjectsAndKeys:@"SubscriptionsController", @"class", [UIImage imageNamed:@"btn_tax.png"], @"icon", @"Abonime", @"title", nil], [NSDictionary dictionaryWithObjectsAndKeys:@"FavoritesController", @"class", [UIImage imageNamed:@"btn_tax.png"], @"icon", @"Abonime", @"title", nil], [NSDictionary dictionaryWithObjectsAndKeys:@"CategoriesController", @"class", [UIImage imageNamed:@"btn_tax.png"], @"icon", @"Abonime", @"title", nil], [NSDictionary dictionaryWithObjectsAndKeys:@"TagsController", @"class", [UIImage imageNamed:@"btn_tax.png"], @"icon", @"Abonime", @"title", nil], [NSDictionary dictionaryWithObjectsAndKeys:@"HelpScreenController", @"class", [UIImage imageNamed:@"btn_tax.png"], @"icon", @"Abonime", @"title", nil], nil]; NSMutableArray *controllerArray = [NSMutableArray array] ; for (NSUInteger i = 0; i < [controllers count]; i++) { id newClass = [[NSClassFromString([[controllers objectAtIndex:i] objectForKey:@"class"]) alloc] init]; UITabBarItem *tabItem = [[UITabBarItem alloc] init]; tabItem.image = [[controllers objectAtIndex:i] objectForKey:@"icon"]; tabItem.title = [[controllers objectAtIndex:i] objectForKey:@"title"]; tabItem.tag = i; [(UIViewController*)newClass setTabBarItem:tabItem]; [tabItem release]; [controllerArray addObject:newClass]; [newClass release]; } tabBar.viewControllers = controllerArray;