当子级vc与父级vc不在同一个情节提要中时，addChild不起作用

Question

我目前正在学习和尝试很多东西，因此我尝试做一个自定义标签栏，而不是使用UITabBar。 为此，我使用了本教程https://guides.codepath.com/ios/Creating-a-Custom-Tab-Bar ，并且当我的子视图控制器与父vc在同一情节提要中一起使用时，一切工作正常（请参见屏幕截图） ： 相同的故事板 ）

但是我只想在主情节提要中拥有主视图控制器，而在自己的情节提要中具有孩子，因为以后会出现更多的视图控制器，因此一切都变得更有条理。

现在的问题是：它像是约束被破坏或其他东西（？）一样接缝。 界面不再正确构建，如您在此屏幕截图中所见： 不同的故事板

如果有人可以帮助我，我会很高兴:)

    @IBOutlet weak var contentView: UIView!
    @IBOutlet weak var fancyTabView: UIView!
    @IBOutlet var fancyTabButtons: [UIButton]!

    var infoViewController: UIViewController!
    var challengesViewController: UIViewController!
    var meViewController: UIViewController!
    var viewControllers: [UIViewController]!

    var selectedIndex = 0

    override func viewDidLoad() {
        super.viewDidLoad()

        infoViewController = UIStoryboard(name: "Info", bundle: nil).instantiateViewController(withIdentifier: "InfoViewController")
        challengesViewController = UIStoryboard(name: "Challenges", bundle: nil).instantiateViewController(withIdentifier: "ChallengesViewController")
        meViewController = UIStoryboard(name: "Me", bundle: nil).instantiateViewController(withIdentifier: "MeViewController")
        viewControllers = [infoViewController, challengesViewController, meViewController]

        // default selected tab button
        fancyTabButtons[selectedIndex].isSelected = true
        didPressTab(fancyTabButtons[selectedIndex])

        configureUI()
    }

    private func configureUI() {
        fancyTabView.layer.cornerRadius = 24
        fancyTabView.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner]
        fancyTabView.layer.shadowColor = UIColor.greyscaleShadow.cgColor
        fancyTabView.layer.shadowOffset = CGSize(width: 0, height: -10)
        fancyTabView.layer.shadowRadius = 40
        fancyTabView.layer.shadowOpacity = 1
    }

    @IBAction func didPressTab(_ sender: UIButton) {
        let previousIndex = selectedIndex
        selectedIndex = sender.tag
        fancyTabButtons[previousIndex].isSelected = false

        let previousVC = viewControllers[previousIndex]
        previousVC.willMove(toParent: nil)
        previousVC.view.removeFromSuperview()
        previousVC.removeFromParent()

        sender.isSelected = true
        let vc = viewControllers[selectedIndex]
        addChild(vc)
        vc.view.frame = contentView.bounds
        contentView.addSubview(vc.view)
        vc.didMove(toParent: self)
    }

当视图控制器一起放在同一情节提要中时，一切工作正常（使用此代码）

infoViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "InfoViewController")
challengesViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ChallengesViewController")
meViewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "MeViewController")

但是当此代码位于不同的情节提要中时，它将无法正常工作

infoViewController = UIStoryboard(name: "Info", bundle: nil).instantiateViewController(withIdentifier: "InfoViewController")
challengesViewController = UIStoryboard(name: "Challenges", bundle: nil).instantiateViewController(withIdentifier: "ChallengesViewController")
meViewController = UIStoryboard(name: "Me", bundle: nil).instantiateViewController(withIdentifier: "MeViewController")