Swift-单击“保存”按钮后无法返回我的主页

Question

我开始使用Xcode和Swift，但现在陷入困境。我在网上学习Apple教程的过程中确实做过，但是我的问题是，保存项目后就无法回到主页。

我对他们的控制器有两个视图：我的主页和新项目页面。 我之间有一个导航控制器，我尝试使用按钮（而不是按钮栏）从主页转到newItem页面。工作正常。

我在我的newItem页面中设置了segue设置和我的prepare函数，但是一旦我填写了所有必填字段，我的Save按钮就启用了，但是当我单击它时什么也没有发生，并且没有任何内容被写为输出来帮助我

这是我的准备和展开功能（进入主页）：

//MARK: Navigation
    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        super.prepare(for: segue, sender: sender)

        switch(segue.identifier ?? "") {
        case "AddLending":
            os_log("Adding a new lending.", log: OSLog.default, type: .debug)

        case "ShowItems":
            guard segue.destination is NewLendingViewController else {
                fatalError("Unexpected destination: \(segue.destination)")
            }

            /*guard let selectedMealCell = sender as? MealTableViewCell else {
                fatalError("Unexpected sender: \(sender)")
            }

            guard let indexPath = tableView.indexPath(for: selectedMealCell) else {
                fatalError("The selected cell is not being displayed by the table")
            }

            let selectedMeal = meals[indexPath.row]
            mealDetailViewController.meal = selectedMeal*/

        default:
            fatalError("Unexpected segue identifier: \(segue.identifier)")
        }
    }

    //MARK: Actions
    // This function is dealing with calling back the homePage once a lending has been created
    @IBAction func unwindToHomePage(sender: UIStoryboardSegue) {
        if let sourceViewController = sender.source as? NewLendingViewController, let lending = sourceViewController.lending {

            money += lending.amount
            updateMoneyButton()
            // Save tne lendings.
            saveLendings()
        }
    }

这是我的newItem页面的prepare函数：

// MARK: - Navigation
    @IBAction func lendingCancelButton(_ sender: UIBarButtonItem) {
        // Depending on style of presentation (modal or push presentation), this view controller needs to be dismissed in two different ways
        let isPresentingInAddLendingMode = presentingViewController is UINavigationController
        if isPresentingInAddLendingMode {
            dismiss(animated: true, completion: nil)
        } else if let owningNavigationController = navigationController {
            owningNavigationController.popViewController(animated: true)
        } else {
            fatalError("the NewLendingViewController is not inside a navigation controller.")
        }
    }


    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        super.prepare(for: segue, sender: sender)

        // Configure the destination view controller only when the saved button is pressed.
        guard let button = sender as? UIBarButtonItem, button === lendingSaveButton else {
            os_log("The saved button was not pressed, cancelling", log: OSLog.default, type: .debug)
            return
        }
        let title = lendingTitle.text ?? ""
        guard let amount = Int(lendingAmount.text ?? "0") else {
            os_log("It seems that the amount entered is incorrect", log: OSLog.default, type: .debug)
            return
        }
        let contact = lendingContact.text ?? ""
        //let date = lendingDate.text ?? ""
        let date = formatStringToDate(date: lendingDate.text ?? "")

        // Set the lending to be passed to HomePageViewController after the unwind segue.
        lending = Lending(amount: amount, title: title, contact: contact, lendingDate: date)

    }

仅需说明一下，我的“取消”按钮可以正常工作，并且可以正确地将我带回到首页。