UITabBar Fuctionality

Question

TabBar不应该启用任何标签，直到用户点击任何一个标签， 下面是我写的代码来显示标签栏，但问题默认情况下它显示第一个标签。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
// Override point for customization after application launch. 
self.window.backgroundColor = [UIColor whiteColor]; 
[self.window makeKeyAndVisible]; 

    PeopleViewController *peopleViewController = [[PeopleViewController alloc] init]; 
UINavigationController *nav1 = [[UINavigationController alloc] initWithRootViewController:peopleViewController]; 
[peopleViewController setTitle:@"People"]; 

EventsViewController *eventsViewController = [[EventsViewController alloc] init]; 
UINavigationController *nav2 = [[UINavigationController alloc]initWithRootViewController:eventsViewController]; 
[eventsViewController setTitle:@"Events"]; 

ActiveViewController *activeViewController = [[ActiveViewController alloc] init]; 
UINavigationController *nav3 = [[UINavigationController alloc]initWithRootViewController:activeViewController]; 
[activeViewController setTitle:@"Active"]; 

MoreViewController *moreViewController = [[MoreViewController alloc] init]; 
UINavigationController *nav4 = [[UINavigationController alloc] initWithRootViewController:moreViewController]; 
[moreViewController setTitle:@"More"]; 

NSArray *arrViewControllers = [[NSArray alloc] initWithObjects:nav1,nav2,nav3,nav4, nil]; 

[tabBarController setViewControllers:arrViewControllers]; 
[self.window addSubview:tabBarController.view]; 
    return YES; 

} 

Answer 1

为标签栏（例如theTabBar）和使用以下代码创建一个IBOutlet：

[theTabBar setSelectedItem:nil];

Answer 2

这是UITabBarController默认行为，默认情况下第一标签被选中。 您可以选择在第一个实例中选择其他选项卡，但不能将选中的默认选项更改为空。

[tabBarController setSelectedIndex:0]; 

默认情况下，选定索引为0，这是第一个选项卡，您可以根据您的要求将其更改为1,2,3。