的TabBar黑屏，无标签

Question

我在didFinishLaunchingWithOptions验证码：

window = UIWindow(frame: UIScreen.mainScreen().bounds) 
    let tabBarController = UITabBarController() 

    let listTableViewController = ListTableViewController() 
    listTableViewController.tabBarItem = UITabBarItem(tabBarSystemItem: .Contacts, tag: 0) 
    var navViewController = UINavigationController(rootViewController: listTableViewController) 
    tabBarController.viewControllers?.append(navViewController) 

    let galleryViewController = GalleryViewController() 
    galleryViewController.tabBarItem = UITabBarItem(tabBarSystemItem: .Featured, tag: 1) 
    navViewController = UINavigationController(rootViewController: galleryViewController) 
    tabBarController.viewControllers?.append(navViewController) 

    let serviceViewController = ServiceViewController() 
    serviceViewController.tabBarItem = UITabBarItem(tabBarSystemItem: .More, tag: 2) 
    navViewController = UINavigationController(rootViewController: serviceViewController) 
    tabBarController.viewControllers?.append(navViewController) 

    tabBarController.selectedIndex = 0 
    window?.rootViewController = tabBarController 
    window?.makeKeyAndVisible() 
    return true 

但是，当应用程序启动和标志不见了我有只黑色的屏幕和标签栏上没有标签，但我希望至少看到来自ListTablevViewController的空表视图。

Answer 1

我下载了你的项目，看起来viewControllers的附加功能无法正常工作，因为tabBarController.viewControllers是零。我做了这个小测试，它工作正常：

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { 
     window = UIWindow(frame: UIScreen.mainScreen().bounds) 
     let tabBarController = UITabBarController() 

     let listTableViewController = ListTableViewController() 
     listTableViewController.tabBarItem = UITabBarItem(tabBarSystemItem: .Contacts, tag: 0) 
     let navViewController = UINavigationController(rootViewController: listTableViewController) 
     tabBarController.viewControllers?.append(navViewController) 

     let galleryViewController = GalleryViewController() 
     galleryViewController.tabBarItem = UITabBarItem(tabBarSystemItem: .Featured, tag: 1) 
     let navViewController1 = UINavigationController(rootViewController: galleryViewController) 
     tabBarController.viewControllers?.append(navViewController) 

     let serviceViewController = ServiceViewController() 
     serviceViewController.tabBarItem = UITabBarItem(tabBarSystemItem: .More, tag: 2) 
     let navViewController2 = UINavigationController(rootViewController: serviceViewController) 
     tabBarController.viewControllers?.append(navViewController) 

     let controllers = [navViewController, navViewController1, navViewController2] 

     tabBarController.selectedIndex = 0 
     tabBarController.viewControllers = controllers 
     window!.rootViewController = tabBarController 
     window!.makeKeyAndVisible() 


     return true 
    }