main.storyboard 없이 하기

sceneDelegate.swift

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
  // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
  // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
  // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).
  guard let windowScene = (scene as? UIWindowScene) else { return }
  window = UIWindow(frame: windowScene.coordinateSpace.bounds)
  window?.windowScene = windowScene
  window?.rootViewController = ViewController()
  window?.makeKeyAndVisible()
}