?varwindow:UIWindow?

? ? funcapplication(_application:UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey:Any]?) ->Bool{

? ? ? ? window = UIWindow(frame: UIScreen.main.bounds)

? ? ? ? letvc =ViewController()

? ? ? ? letnavVC =UINavigationController(rootViewController: vc)

? ? ? ? window?.rootViewController = navVC

? ? ? ? window?.makeKeyAndVisible(）

? ? ? ? return true

? ? }