set initial viewcontroller in appdelegate – swift

Xcode11 and SceneDelegate note:

Starting from Xcode11, because of SceneDelegates, it’s likely that you shouldn’t do it inside AppDelegate. Instead do it from SceneDelegate. For more on that see this other answer

Old answer:

I used this thread to help me convert the objective C to swift, and its working perfectly.

Instantiate and Present a viewController in Swift

Swift 2 code:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
    
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    
    let initialViewController = storyboard.instantiateViewControllerWithIdentifier("LoginSignupVC")
    
    self.window?.rootViewController = initialViewController
    self.window?.makeKeyAndVisible()
    
    return true
}

Swift 3 code:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    self.window = UIWindow(frame: UIScreen.main.bounds)

    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    
    let initialViewController = storyboard.instantiateViewController(withIdentifier: "LoginSignupVC")

    self.window?.rootViewController = initialViewController
    self.window?.makeKeyAndVisible()

    return true
}