func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        self.window = UIWindow(frame: UIScreen.main.bounds)
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        if (PreferenceHelper.getAccessToken() != "") {
            let initialViewController = storyboard.instantiateViewController(withIdentifier: "your View Controller Identifier")
            self.window?.rootViewController = initialViewController
        } else {
            let initialViewController = storyboard.instantiateViewController(withIdentifier: "your View Controller identifier")
            self.window?.rootViewController = initialViewController
        }
        self.window?.makeKeyAndVisible()
        return true
    }

/*
use your view Controller identifier must use it doubles quotes**strong text**

在AppDelegate.swift中，你可以添加以下代码:

let sb = UIStoryboard(name: "Main", bundle: nil)
let vc = sb.instantiateViewController(withIdentifier: "YourViewController_StorboardID")
self.window?.rootViewController = vc
self.window?.makeKeyAndVisible()

当然，你需要实现你的逻辑，基于什么标准你将选择一个合适的视图控制器。

另外，不要忘记添加一个标识(select storyboard -> Controller Scene -> Show the identity inspector -> assign StorboardID)。

Swift 4, Xcode 9

在AppDelegate.swift文件中

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let firstVC = storyboard.instantiateViewController(withIdentifier: "firstViewController") as! firstViewController
    self.window?.rootViewController = firstVC
}

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()
    }

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
}

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。