如何使它成为我的页面视图控制器不是永无止境的？

我有一个页面视图控制器，允许我滚动浏览各种注册页面并输入必要的信息。问题是它只是滚动一圈。我如何制作它，以便PlayerInfo页面是我可以滚动到的最后一页？如何使它成为我的页面视图控制器不是永无止境的？

lazy var SignupArray : [UIViewController] = { 
    return [self.VCInstance(name: "ParkSelect"), 
      self.VCInstance(name: "SportSelect"), 
      self.VCInstance(name: "PlayerInfo")] 
}() 

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

override func viewDidLoad() { 
    super.viewDidLoad() 

    self.dataSource = self 
    self.delegate = self 

    if let firstVC = SignupArray.first { 
     setViewControllers([firstVC], direction: .forward, animated: true, completion: nil) 

    } 
} 

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

    let previousIndex = viewControllerIndex - 1 

    guard previousIndex >= 0 else { 
     return SignupArray.last 
    } 

    guard SignupArray.count > previousIndex else { 
     return nil 
    } 

    return SignupArray[previousIndex] 
} 

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

    let nextIndex = viewControllerIndex + 1 

    guard nextIndex < SignupArray.count else { 
     return SignupArray.first 
    } 

    guard SignupArray.count > nextIndex else { 
     return nil 
    } 

    return SignupArray[nextIndex] 
}

来源

2017-09-14 Alexander

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

    let previousIndex = viewControllerIndex - 1 

    guard previousIndex >= 0 else { 
     return nil 
    } 

    return SignupArray[previousIndex] 
} 


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

    let nextIndex = viewControllerIndex + 1 

    guard SignupArray.count > nextIndex else { 
     return nil 
    } 

    return SignupArray[nextIndex] 
}

的原因是因为

时previousIndex变为零传递最后一个VC的阵列

guard previousIndex >= 0 else { 
    return SignupArray.last 
}

时nextIndex等于算注册阵列u的传递是无止境阵列中的第一个VC。

guard nextIndex < SignupArray.count else { 
    return SignupArray.first 
}

删除这两个代码和UR PageViewer将停止

来源

2017-09-14 16:32:09

介意告诉我你更改或添加什么？ – Alexander

@Alexander：正在输入解释发布的代码第一个即所有 –

现在，页面根本不滚动。 – Alexander

返回nil代替缠绕的。例如：

public func pageViewController(_ pvc: UIPageViewController, viewControllerAfter vc: UIViewController) -> UIViewController?{ 
    guard 
     let i = SignupArray.index(of: vc), 
     i < SignupArray.count - 1 
    else { 
     return nil 
    } 
    return SignupArray[i + 1] 
}

，或者更简洁：

public func pageViewController(_ pvc: UIPageViewController, viewControllerAfter vc: UIViewController) -> UIViewController?{ 
    let i = 1 + (SignupArray.index(of: vc) ?? SignupArray.count) 
    return i < SignupArray.count ? SignupArray[i] : nil 
}

来源

2017-09-14 16:33:30

如何使它成为我的页面视图控制器不是永无止境的？

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