Q&A
そのアプリの対応 iOS バージョンは？ また、SwiftUI を使用しますか？
実現したいこと
・SceneDelegate.swiftを後から追加したい。
現状
SceneDelegate.swiftがデフォルトで追加される前のverのXcodeでプログラムを作成していました。
新規で別のプロジェクトを作成して、SceneDelegate.swiftを移植先に移すとエラーがでます。
全体のソースコード
import UIKit import SwiftUI class SceneDelegate: UIResponder, UIWindowSceneDelegate { var window: UIWindow? 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). // Create the SwiftUI view that provides the window contents. let contentView = ContentView() // Use a UIHostingController as window root view controller. if let windowScene = scene as? UIWindowScene { let window = UIWindow(windowScene: windowScene) window.rootViewController = UIHostingController(rootView: contentView) self.window = window window.makeKeyAndVisible() } } func sceneDidDisconnect(_ scene: UIScene) { // Called as the scene is being released by the system. // This occurs shortly after the scene enters the background, or when its session is discarded. // Release any resources associated with this scene that can be re-created the next time the scene connects. // The scene may re-connect later, as its session was not neccessarily discarded (see `application:didDiscardSceneSessions` instead). } func sceneDidBecomeActive(_ scene: UIScene) { // Called when the scene has moved from an inactive state to an active state. // Use this method to restart any tasks that were paused (or not yet started) when the scene was inactive. } func sceneWillResignActive(_ scene: UIScene) { // Called when the scene will move from an active state to an inactive state. // This may occur due to temporary interruptions (ex. an incoming phone call). } func sceneWillEnterForeground(_ scene: UIScene) { // Called as the scene transitions from the background to the foreground. // Use this method to undo the changes made on entering the background. } func sceneDidEnterBackground(_ scene: UIScene) { // Called as the scene transitions from the foreground to the background. // Use this method to save data, release shared resources, and store enough scene-specific state information // to restore the scene back to its current state. } }
エラーメッセージ（一部）
試したこと
多すぎたのでひとまずFIXで直せるものは上から順に変更しました。
変更後のソースコード
import UIKit import SwiftUI class SceneDelegate: UIResponder, UIWindowSceneDelegate { var window: UIWindow? @available(iOS 13.0, *) 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). // Create the SwiftUI view that provides the window contents. let contentView = ContentView() // Use a UIHostingController as window root view controller. if let windowScene = scene as? UIWindowScene { let window = UIWindow(windowScene: windowScene) window.rootViewController = UIHostingController(rootView: contentView) self.window = window window.makeKeyAndVisible() } } @available(iOS 13.0, *) func sceneDidDisconnect(_ scene: UIScene) { // Called as the scene is being released by the system. // This occurs shortly after the scene enters the background, or when its session is discarded. // Release any resources associated with this scene that can be re-created the next time the scene connects. // The scene may re-connect later, as its session was not neccessarily discarded (see `application:didDiscardSceneSessions` instead). } @available(iOS 13.0, *) func sceneDidBecomeActive(_ scene: UIScene) { // Called when the scene has moved from an inactive state to an active state. // Use this method to restart any tasks that were paused (or not yet started) when the scene was inactive. } @available(iOS 13.0, *) func sceneWillResignActive(_ scene: UIScene) { // Called when the scene will move from an active state to an inactive state. // This may occur due to temporary interruptions (ex. an incoming phone call). } @available(iOS 13.0, *) func sceneWillEnterForeground(_ scene: UIScene) { // Called as the scene transitions from the background to the foreground. // Use this method to undo the changes made on entering the background. } @available(iOS 13.0, *) func sceneDidEnterBackground(_ scene: UIScene) { // Called as the scene transitions from the foreground to the background. // Use this method to save data, release shared resources, and store enough scene-specific state information // to restore the scene back to its current state. } }
エラー内容
新規で作り直さないと厳しいのでしょうか。
hoshi-takanori様
コメントありがとうございます。
バージョンは12.4
SwiftUI はつかいません。
iOS 12.4 には SceneDelegate は存在しないので、iOS 12.4 では SceneDelegate は使わずに今まで通りの挙動、iOS 13 以降では SceneDelegate を使用するという場合分けのコードが必要になります。また、質問文の SceneDelegate は SwiftUI を使う前提のものなので、使わないのであればそのように修正（または、SwiftUI を使わない設定せ新規プロジェクトを生成して、その SceneDelegate を使用）する必要があります。自分はまだ SceneDelegate は詳しくないので、詳細な方法は分かりません。
hoshi-takanori様
ご返答ありがとうございます。
場合分けのコードが必要なのですね。。
もう少し考えてみます！いつもありがとうございます。
たぶん古い Xcode で作ったプロジェクトをそのまま新しい Xcode でビルドしても、しばらくは大丈夫だと思うので、iOS 12 の対応も必要であれば、急いで SceneDelegate に移行しなくても良いのではないかと思います。
自己解決
