ios - 将导航 Controller 嵌入到选项卡栏 Controller 中

Question

我目前有一个从ViewController分离出来的DetailViewController，它嵌入在UINavigationViewController中，我想将其嵌入 >UITabBarController。当我第一次在 storyboard 上执行此操作时，我的应用程序崩溃并出现错误:

"Could not cast value of type 'UITabBarController' (0x10badf258) to 'UINavigationController' (0x10badf208)".

经过研究，我添加了前两行(let tabVc =，并let navVc =)，但仍然崩溃。为了创建一个成功的 TabBarController，我缺少什么？

 override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    let tabVc = segue.destinationViewController as! UITabBarController
    let navVc = tabVc.viewControllers!.first as! UINavigationController

    if segue.identifier == "ShowItem" {
        if let row = tableView.indexPathForSelectedRow?.row {
            let item = itemStore.allItems[row]
            let detailViewController = segue.destinationViewController as! DetailViewController
            detailViewController.item = item
            detailViewController.imageStore = imageStore
        }
    }
}

更新:应用更改后，我的错误已更改为

"Could not cast value of type 'UITabBarController' (0x103ff6258) to 'Photomania.ItemsViewController' (0x1029520d0)."

Error

Answer 1

我认为您处理问题的方式是错误的。您可以在其viewDidLoad中设置ItemsViewController的imageStore和itemStore。

override func viewDidLoad() {
    super.viewDidLoad()
    self.itemStore  = ItemStore()
    self.imageStore = ImageStore()
}

但是，如果您希望在 AppDelegate 的 didFinishLaunchingWithOptions 中执行此操作，那么您可以这样做。

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.

    let rootController = window?.rootViewController

    if rootController is UITabBarController {
        let firstTabItem = (rootController as! UITabBarController).viewControllers?[0]

        if firstTabItem is UINavigationController {

            let firstController = (firstTabItem as! UINavigationController).viewControllers.first as! ItemsViewController
            firstController.itemStore  = ItemStore()
            firstController.imageStore = ImageStore()
        }
    }
}