谢谢在AppDelegate中修改如下:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) ->     Bool {
//Some code to check value of pins

if pins! == "Verified"{
        print(pins)
        self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
        let mainStoryboard: UIStoryboard = UIStoryboard(name: "HomePage", bundle: nil)
        let exampleViewController: UINavigationController = mainStoryboard.instantiateViewControllerWithIdentifier("SBHP") as! UINavigationController

        self.window?.rootViewController = exampleViewController

        self.window?.makeKeyAndVisible()
    }else{
        print(pins)
        self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
        let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        let exampleViewController: UINavigationController = mainStoryboard.instantiateViewControllerWithIdentifier("SBUser") as! UINavigationController

        self.window?.rootViewController = exampleViewController

        self.window?.makeKeyAndVisible()
    }

选择要首先打开的视图控制器，然后转到属性检查器。 转到初始场景，检查初始视图控制器选项。

这是你的初始视图控制器在应用启动时首先打开。

如果你不想改变applicationDidFinish，你可以做下面的技巧:

设置导航控制器为初始视图控制器，并分配给它一个自定义类'MyNavigationController'。然后你可以在viewDidLoad期间调整它的根视图控制器——它会覆盖你在故事板中设置的根视图控制器。

class MyNavigationController: UINavigationController {
    override func viewDidLoad() {
        super.viewDidLoad()
        if !isLoggedIn() {
            viewControllers = [R.storyboard.authentication.loginView()!]
        }
    }

    private func isLoggedIn() -> Bool {
        return false
    }

}

使用Swift 3和Swift 4避免强制铸造的另一个解决方案是这样的

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.main.bounds)
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    guard let viewController = storyboard.instantiateViewController(withIdentifier: "YourViewController") as? YourViewController else {
        return false
    }
    self.window?.rootViewController = viewController
    self.window?.makeKeyAndVisible()
    return true
}

下面是使用UINavigationController

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.main.bounds)
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    guard let viewController = storyboard.instantiateViewController(withIdentifier: "YourViewController") as? YourViewController else {
        return false
    }
    let navigationController = UINavigationController(rootViewController: viewController)
    self.window?.rootViewController = navigationController
    self.window?.makeKeyAndVisible()
    return true
}

找到了简单的解决方案-不需要从故事板和编辑项目信息选项卡中删除“初始视图控制器检查”，并使用makeKeyAndVisible，只是放置

self.window.rootViewController = rootVC;

in

- (BOOL) application:didFinishLaunchingWithOptions:

打开mainstoryboard，首先选择要启动的视图，然后打开Utilities—> Attributes。在“视图控制器”下面，你会看到“Is initial View Controller”单选按钮。选择它。

——对修改后的问题:

也许你可以试试这个:在你的初始视图的ViewDidLoad部分写一个方法，当这个方法在应用程序启动时运行，方法触发一个到另一个视图的segue。