Swift 为什么将my UIPageViewController的转换样式更改为.scroll会使所有UIViewController消失？

我正在尝试将UIPageViewController的转换样式从默认的pageCurl更改为scroll。我试着用程序来完成这一切。在下面显示的代码中，当注释掉这两个init函数时，我的两个视图控制器，

teamVC

和

teamVC2

显示得非常好

override init(transitionStyle style: UIPageViewController.TransitionStyle, navigationOrientation: UIPageViewController.NavigationOrientation, options: [UIPageViewController.OptionsKey : Any]? = nil) {
    super.init(transitionStyle: .scroll, navigationOrientation: .horizontal, options: nil)
}

required init?(coder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

然而，当他们留在我运行的代码，没有出现在屏幕上

class PagingViewController: UIPageViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate {

var teamViewControllers: [UIViewController] = []

func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
    let currentIndex = teamViewControllers.firstIndex(of: viewController) ?? 0
    if currentIndex <= 0 {
        return nil
    }
    return teamViewControllers[currentIndex - 1]
}

func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
    let currentIndex = teamViewControllers.firstIndex(of: viewController) ?? 0
    if currentIndex >= teamViewControllers.count - 1 {
        return nil
    }
    return teamViewControllers[currentIndex + 1]
}
func presentationCount(for pageViewController: UIPageViewController) -> Int {
    return teamViewControllers.count
}

//this function and the required init function below make my view controllers disappear
override init(transitionStyle style: UIPageViewController.TransitionStyle, navigationOrientation: UIPageViewController.NavigationOrientation, options: [UIPageViewController.OptionsKey : Any]? = nil) {
    super.init(transitionStyle: .scroll, navigationOrientation: .horizontal, options: nil)
}

required init?(coder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

override func viewDidLoad() {
    super.viewDidLoad()

    self.delegate = self
    self.dataSource = self

    let teamVC = TeamViewController()
    teamVC.teamName = "Atlanta Hawks"
    teamViewControllers.append(teamVC)

    let teamVC2 = TeamViewController()
    teamVC2.teamName = "Boston Celtics"
    teamViewControllers.append(teamVC2)

    setViewControllers([teamViewControllers[0]], direction: .forward, animated: true, completion: nil)
}
}

class PagingViewController:UIPageViewController、UIPageViewControllerDataSource、UIPageViewControllerDelegate{
var TeamViewController:[UIViewController]=[]
func pageViewController（uPageViewController:UIPageViewController，viewController在viewController:UIViewController之前）->UIViewController{
让currentIndex=TeamViewController.firstIndex（of:viewController）？？0
如果是currentIndex UIViewController{
让currentIndex=TeamViewController.firstIndex（of:viewController）？？0
如果currentIndex>=TeamViewController.count-1{
归零
}
返回TeamViewController[currentIndex+1]
}
func presentationCount（对于pageViewController:UIPageViewController）->Int{
返回teamViewControllers.count
}
//此函数和下面所需的init函数使my view控制器消失
重写初始化（transitionStyle:UIPageViewController.transitionStyle，navigationOrientation:UIPageViewController.navigationOrientation，选项：[UIPageViewController.OptionKey:Any]？=nil）{
super.init（transitionStyle:.滚动，navigationOrientation:.水平，选项：nil）
}
必需初始化？（编码器：NSCoder）{
fatalError（“初始化（编码者：）尚未实现”）
}
重写func viewDidLoad（）{
super.viewDidLoad（）
self.delegate=self
self.dataSource=self
让teamVC=TeamViewController（）
teamVC.teamName=“亚特兰大鹰队”
TeamViewController.append（teamVC）
让teamVC2=TeamViewController（）
teamVC2.teamName=“波士顿凯尔特人”
TeamViewController.append（teamVC2）
SetViewController（[TeamViewController[0]]，方向：。正向，动画：true，完成：nil）
}
}

我看不到任何创建PagingViewController并将其放在屏幕上的代码。它在哪里？为什么要重写

init

？你应该只调用

init

，而不是重写它。另外，让页面视图控制器成为它自己的委托是一个非常糟糕的主意。一般来说，这不是视图控件oller说，您应该完全需要子类化。