didfinishlaunchingwithoptions launchoptions是零

Question

我正在尝试将我的onBoarding屏幕设置为应用委托中的rootViewController，但由于某种原因崩溃，我已经尝试追找原因并找不到任何原因。此行崩溃int。

let intialViewcontroller = storyboard.instantiateViewController(withIdentifier: "onBoarding")

记录

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        UIApplication.shared.statusBarStyle = .lightContent
        if let barFont = UIFont(name: "AvenirNext-DemiBold", size: 24.0) {
            UINavigationBar.appearance().titleTextAttributes =
                [NSForegroundColorAttributeName:UIColor.white, NSFontAttributeName:barFont]
        }

        FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions)
        FirebaseApp.configure()

        window = UIWindow(frame: UIScreen.main.bounds)
        let storyboard = UIStoryboard(name: "Main", bundle: nil)

        let intialViewcontroller = storyboard.instantiateViewController(withIdentifier: "onBoarding")

        window?.rootViewController = intialViewcontroller
        window?.makeKeyAndVisible()

        return true
    }