Suddenly, the problem was solved. What I did was simple, I just changed the function name as follows: onReturn() -> toReverse() I don't know the cause, but since the previous reply said the following, I tried the simplest thing to do, which is to change the name, and the problem was solved. Thank you. "Try rewriting that code a little bit to achieve the same goal"

Program including onReturn() is below. class PhotosViewer: UIViewController { override func viewDidLoad() { super.viewDidLoad() // ダウン対策 if newImageDT.count <= page || page < 0 { page = newImageDT.count - 1 } initImageView(image1: newImageDT[page]) if newImageDT.count - 1 > page { let rightButton = UIBarButtonItem(title: "button_next".localized, style: UIBarButtonItem.Style.plain, target: self, action: #selector(onNext)) self.navigationItem.rightBarButtonItem = rightButton } else { let rightButton = UIBarButtonItem(title: "".localized, style: UIBarButtonItem.Style.plain, target: self, action: #selector(onNext)) self.navigationItem.rightBarButtonItem = rightButton } let leftButton = UIBarButtonItem(title: "menu_Return".localized, style: UIBarButtonItem.Style.plain, target: self, action: #selector(onReturn)) self.navigationItem.leftBarButtonItem = leftButton self.navigationItem.title = shotDates[page] let cDateTime = cm.datestring(targetDate: Date(), format: "yyyy-MM-dd HH:mm:ss") let parm = "checkAt=cast(\"" + cDateTime + "\" as datetime), checkBy=\"" + accountantName + "\" WHERE id = \"" + contract.contID + "\" AND file_name = \"" + fileNames[page] + "\" AND checkBy = \"\"" // 画像確認記録を登録 let currentPage = page db.updateImage(fileName: fileNames[currentPage], parm: parm) { [self] completion in if completion == 0 { dm.updateImagerecord(fileName: fileNames[currentPage], checkAt: cDateTime, checkBy: accountantName) // 内部データも更新 } } let pinchGesture = UIPinchGestureRecognizer() pinchGesture.addTarget(self, action: #selector(pinchAction(_:) ) ) view.addGestureRecognizer(pinchGesture) let rotateGesture = UIRotationGestureRecognizer() rotateGesture.addTarget(self, action: #selector(rotateAction(_:) ) ) view.addGestureRecognizer(rotateGesture) let panOrSwipe = UIPanGestureRecognizer(target: self, action: #selector(didPan(_:))) view.addGestureRecognizer(panOrSwipe) let tapGesture = UITapGestureRecognizer() tapGesture.addTarget(self, action: #selector(tapAction(_:))) view.addGestureRecognizer(tapGesture) let longPressGesture = UILongPressGestureRecognizer() longPressGesture.addTarget(self, action: #selector(longPressAction(_:))) view.addGestureRecognizer(longPressGesture) } 〜 〜 〜 @objc func onReturn() { page -= 1 if page > 0 { self.loadView() self.viewDidLoad() return } else { self.navigationController?.popViewController(animated: true) return } } 〜 〜 〜 } onReturn() is in Line 173. This file displays images. onReturn() returns the image to the previous one, or returns to the screen it was called from if all images have been returned. I do not know what is the FB number.