使用Xcode 11.2中的故事板以编程方式设置初始视图控制器。

Question

使用Xcode 11.2中的故事板以编程方式设置初始视图控制器。

6

我正在尝试以编程方式设置初始视图控制器，但我一直收到这个错误。有什么解决办法吗？

2019-11-07 11:47:43.975990+0000 RestaurantApp[16319:147412] [WindowScene] Failed to instantiate the default view controller for UIMainStoryboardFile 'Main' - perhaps the designated entry point is not set?

这是我编写的代码。

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {


    let window = UIWindow()
    let locationService = LocationService()
    let storyboard = UIStoryboard(name: "Main", bundle: nil) //refernce to our storyboard





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

        //setiing the root view control on our window
        switch locationService.status  {
        case .notDetermined, .denied, .restricted:
            let LocationViewController =
                storyboard.instantiateViewController (withIdentifier: "LocationViewController") as? LocationViewController
            LocationViewController?.locationService = locationService
                window.rootViewController = LocationViewController
        default:
            assertionFailure()
        }

        window.makeKeyAndVisible()

        return true
    }
}

这是我故事板的图片：

- M B

你能发布你的故事板结构吗？ - Maulik Pandya

你的Storyboard的名称真的是“Main”吗？ - Daniel Storm

4个回答

4

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.
            let storyboard = UIStoryboard.init(name: "Main", bundle: nil)
     let homeView =  storyboard.instantiateViewController(withIdentifier: "ViewController") as! ViewController
     self.window?.rootViewController = homeView
    return true
}

这对我有效

- Adarsh KC

1

这个错误是由于你的故事板中出现了一个简单的错误，很容易修复。当你的应用程序启动时，iOS需要准确地知道哪个视图控制器需要首先显示 - 也就是你的默认视图控制器。

如果你不小心删除了该视图控制器或者使其不再是默认值，则会看到错误消息“Failed to instantiate the default view controller for UIMainStoryboardFile 'Main' - perhaps the designated entry point is not set?”，并且会出现一个纯黑色屏幕。

要解决问题，请打开你的Main.storyboard文件，找到你想要在应用程序第一次运行时显示的任何视图控制器。当它被选中时，转到属性检查器并勾选标记为“Is Initial View Controller”的框。你应该会看到一个右箭头出现在该视图控制器左侧，表示它是你故事板的入口点。

- SGDev

0

返回Storyboard并将此选项勾选，以使您的应用程序启动时进入所需的viewController。

- Frostmourne

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- flanker · Accepted Answer

iOS 13已将窗口设置从AppDelegate移至SceneDelegate，以支持使用（可能多个）场景而不是单个窗口。现在您需要像这样进行设置：

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

   var window: UIWindow?
   let storyboard = UIStoryboard(name: "Main", bundle: nil)

   func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
      guard let windowScene = scene as? UIWindowScene else { return }
      let vc = storyboard.instantiateViewController (withIdentifier: "Primary") as! ViewController
      window = UIWindow(windowScene: windowScene)
      window?.rootViewController = vc
      window?.makeKeyAndVisible()
   }