Swift AppDelegate ViewController

AppDelegate.swift

var window: UIWindow?


func application(application: UIApplication!, didFinishLaunchingWithOptions launchOptions: NSDictionary!) -> Bool {
        // Override point for customization after application launch.
        
        window = UIWindow(frame: UIScreen.mainScreen().bounds)
        window?.rootViewController = ViewController()
        window?.makeKeyAndVisible()
        return true
    }

Objective-C is UIViewController in AppDelegate.