将变量从页面视图控制器传递到另一个

我正在尝试使用 制作注册表单UIPageViewController，因此我正在尝试将变量从子视图传递到另一个视图。

这是我的页面视图控制器：

    class PageViewController: UIPageViewController, UIPageViewControllerDelegate, UIPageViewControllerDataSource {


var pageControl = UIPageControl()

// MARK: UIPageViewControllerDataSource

lazy var orderedViewControllers: [UIViewController] = {
    return [self.newVc(viewController: "First"),
            self.newVc(viewController: "Second"),
            self.newVc(viewController: "Third")]
}()

override func viewDidLoad() {
    super.viewDidLoad()
    self.dataSource = self
    self.delegate = self



    // This sets up the first view that will show up on our page control
    if let firstViewController = orderedViewControllers.first {
        setViewControllers([firstViewController],
                           direction: .forward,
                           animated: true,
                           completion: nil)
    }

    configurePageControl()

    // Do any additional setup after loading the view.
}

func configurePageControl() {
    // The total number of pages that are available is based on how many available colors we have.
    pageControl = UIPageControl(frame: CGRect(x: 0,y: UIScreen.main.bounds.maxY - 50,width: UIScreen.main.bounds.width,height: 50))
    self.pageControl.numberOfPages = orderedViewControllers.count
    self.pageControl.currentPage = 0
    self.pageControl.tintColor = UIColor.black
    self.pageControl.pageIndicatorTintColor = UIColor.white
    self.pageControl.currentPageIndicatorTintColor = UIColor.black
    self.view.addSubview(pageControl)
}

func newVc(viewController: String) -> UIViewController {
    return UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: viewController)
}


// MARK: Delegate methords
func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
    let pageContentViewController = pageViewController.viewControllers![0]
    self.pageControl.currentPage = orderedViewControllers.index(of: pageContentViewController)!
}

// MARK: Data source functions.
func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
    guard let viewControllerIndex = orderedViewControllers.index(of: viewController) else {
        return nil
    }

    let previousIndex = viewControllerIndex - 1

    // User is on the first view controller and swiped left to loop to
    // the last view controller.
    guard previousIndex >= 0 else {
        return orderedViewControllers.last
        // Uncommment the line below, remove the line above if you don't want the page control to loop.
        // return nil
    }

    guard orderedViewControllers.count > previousIndex else {
        return nil
    }

    return orderedViewControllers[previousIndex]
}

func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
    guard let viewControllerIndex = orderedViewControllers.index(of: viewController) else {
        return nil
    }

    let nextIndex = viewControllerIndex + 1
    let orderedViewControllersCount = orderedViewControllers.count

    // User is on the last view controller and swiped right to loop to
    // the first view controller.
    guard orderedViewControllersCount != nextIndex else {
        return orderedViewControllers.first
        // Uncommment the line below, remove the line above if you don't want the page control to loop.
        // return nil
    }

    guard orderedViewControllersCount > nextIndex else {
        return nil
    }

    return orderedViewControllers[nextIndex]

这是我的注册控制器

class RegisterViewController: UIViewController {
var username = ""
var email  = ""
var password = ""
var money = ""
var usn  = ""
@IBOutlet weak var textUsername: UITextField!
@IBOutlet weak var textEmail: UITextField!
@IBOutlet weak var textPassword: UITextField!
@IBOutlet weak var textMoney: UITextField!
@IBOutlet weak var labelUsername: UILabel!


@IBAction func btnValidate(_ sender: Any) {
    username = textUsername.text!
    usn = username
    email = textEmail.text!
    password = textPassword.text!
    print (username)
 //   labelUsername.text = username
  //  API.register(username: username, email: email, password: password)

}

@IBAction func btnSaveMoney(_ sender: Any) {
    money = String(textMoney.text!)
    print(money)
    print(username)

}
@IBAction func btnBegin(_ sender: Any) {
//   API.setMoney(money: money, username: username)
//   print(textMoney.text!)
    print("your name"+usn)
}
override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
}


/*
// 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?) {
    // Get the new view controller using segue.destination.
    // Pass the selected object to the new view controller.
}
*/

我的主要目标是将用户名从第一个孩子传递给第二个孩子，以便我可以使用它来使用网络服务这些是我的故事板和我的注册表单

故事板

我试图在第一页上获取用户名、密码和电子邮件，然后将用户名传递给下一个子视图，以便我可以将金额发送到数据库