版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/xiongya8888/article/details/88021708
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
let storyboard=UIStoryboard(name: "LoginViewController", bundle: nil)
let loginView=storyboard.instantiateViewController(withIdentifier: "LoginViewController") as! LoginViewController
window?.rootViewController=loginView;
return true
}