Swift UIPageControl以编程方式点不再出现

Question

需要一些帮助。我已经实现了一个uipagecontrol，其中以编程方式添加点。它只是工作。我没有触及代码，但我正在编写故事板中的UI。然后我跑了它们，它们已经消失了。我尝试使用调试工具View Hierarchy但没有运气。他们没有出现在那里。我可以在故事板中处理用户界面吗？

import UIKit

class EmployeeTutorialViewController: UIPageViewController, UIPageViewControllerDelegate, UIPageViewControllerDataSource {

var pageControl = UIPageControl()

// MARK: UIPageViewControllerDataSource

lazy var orderedViewControllers: [UIViewController] = {
    return [self.newVc(viewController: "employee1"),
            self.newVc(viewController: "employee2"),
            self.newVc(viewController: "employee3"),
            self.newVc(viewController: "employee4"),
            self.newVc(viewController: "employee5"),
            self.newVc(viewController: "employee6"),
            self.newVc(viewController: "employee7"),
            self.newVc(viewController: "employee8")]
}()

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.gray
    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]
}

}