如何在滑动PageViewController页面时保存用户输入的数据？

// 数据模型
struct UserData {
    var page1Data: String = ""
    var page2Data: String = ""
    var page3Data: String = ""
}

class MyPageViewController: UIPageViewController, UIPageViewControllerDelegate {
    var userData = UserData()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置代理
        self.delegate = self
    }
    
    // 页面切换前保存数据
    func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
        guard let nextViewController = pendingViewControllers.first as? MyContentViewController else {
            return
        }
        
        // 根据页面索引保存对应的数据
        let currentIndex = nextViewController.pageIndex
        switch currentIndex {
        case 0:
            userData.page1Data = nextViewController.textField.text ?? ""
        case 1:
            userData.page2Data = nextViewController.textField.text ?? ""
        case 2:
            userData.page3Data = nextViewController.textField.text ?? ""
        default:
            break
        }
    }
    
    // 页面切换完成后恢复数据
    func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
        guard let currentViewController = pageViewController.viewControllers?.first as? MyContentViewController else {
            return
        }
        
        // 根据页面索引恢复对应的数据
        let currentIndex = currentViewController.pageIndex
        switch currentIndex {
        case 0:
            currentViewController.textField.text = userData.page1Data
        case 1:
            currentViewController.textField.text = userData.page2Data
        case 2:
            currentViewController.textField.text = userData.page3Data
        default:
            break
        }
    }
}

class MyContentViewController: UIViewController {
    @IBOutlet weak var textField: UITextField!
    var pageIndex: Int = 0
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 在视图加载时填充数据
        let pageViewController = self.parent as? MyPageViewController
        switch pageIndex {
        case 0:
            textField.text = pageViewController?.userData.page1Data
        case 1:
            textField.text = pageViewController?.userData.page2Data
        case 2:
            textField.text = pageViewController?.userData.page3Data
        default:
            break
        }
    }
}