以编程方式添加 TabBarController

我想以编程方式制作标签栏控制器和导航控制器。到目前为止，我的代码有效，它在底部显示了一个选项卡栏，但 OptionViewController 在第二个选项卡栏的按钮上没有说任何内容（没有标题）。有趣的是，当我单击没有任何内容的按钮时，标题出现（他的视图也是如此），有人可以向我解释我做错了什么吗？我尝试使用以下代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{    
    // Override point for customization after application launch.
    [self.window makeKeyAndVisible];

    NSMutableArray *tabItems = [[NSMutableArray alloc] initWithCapacity:2];

    DefaultViewController *dvc = [[DefaultViewController alloc] init];
    UINavigationController *dvc_nc = [[UINavigationController alloc] initWithRootViewController:dvc];
    [tabItems addObject:dvc_nc];
    [dvc release];
    [dvc_nc release];

    OptionsViewController *ovc = [[OptionsViewController alloc] initWithStyle:UITableViewStyleGrouped];
    UINavigationController *ovc_nc = [[UINavigationController alloc] initWithRootViewController:ovc];
    [tabItems addObject:ovc_nc];
    [ovc release];
    [ovc_nc release];

    UITabBarController *tbc = [[UITabBarController alloc] init];
    tbc.viewControllers = tabItems;
    self.tabController = tbc;
    [tabItems release];
    [tbc release];

    [self.window addSubview:self.tabController.view];

    return YES;
}

您需要设置 tabBarItem 和标题UINavigationController而不是它的根 viewController。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{    
    // Override point for customization after application launch.
    [self.window makeKeyAndVisible];

    NSMutableArray *tabItems = [[NSMutableArray alloc] initWithCapacity:2];

    DefaultViewController *dvc = [[DefaultViewController alloc] init];
    UINavigationController *dvc_nc = [[UINavigationController alloc] initWithRootViewController:dvc];
    dvc_nc.tabBarItem.title = @"Default";
    dvc_nc.tabBarItem.image = [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"Default" ofType:@"png"]];
    [tabItems addObject:dvc_nc];
    [dvc release];
    [dvc_nc release];

    OptionsViewController *ovc = [[OptionsViewController alloc] initWithStyle:UITableViewStyleGrouped];
    UINavigationController *ovc_nc = [[UINavigationController alloc] initWithRootViewController:ovc];
    ovc_nc.tabBarItem.title = @"Option"
    ovc_nc.tabBarItem.image = [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"Optiomn" ofType:@"png"]];

    [tabItems addObject:ovc_nc];
    [ovc release];
    [ovc_nc release];

    UITabBarController *tbc = [[UITabBarController alloc] init];
    tbc.viewControllers = tabItems;
    self.tabController = tbc;
    [tabItems release];
    [tbc release];

    [self.window addSubview:self.tabController.view];

    return YES;
}