错误：页面控制在单页交换时跳转两次

Question

使用以下代码，页面控件在单页交换期间跳转了两次而不是一次。我需要将import UIKit class ViewController: UIViewController, UIPageViewControllerDataSource, UIPageViewControllerDelegate{ var pageViewController: UIPageViewController! let pagesArray = ["Page1ViewController", "Page2ViewController","Page3ViewController"] let pageControl : UIPageControl = UIPageControl(frame: CGRectMake(100, 600, 200, 20)) func viewControllerAtIndex(index: Int) -> UIViewController? { let vc = storyboard?.instantiateViewControllerWithIdentifier (pagesArray[index]) return vc } func pageViewController(pageViewController:UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController?{ if var index = pagesArray.indexOf(viewController.restorationIdentifier!){ if index > 0 { index-- self.pageControl.currentPage = index return viewControllerAtIndex(index) } } return nil } func pageViewController(pageViewController:UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController?{ if var index = pagesArray.indexOf(viewController.restorationIdentifier!){ if index < pagesArray.count - 1 { index++ return viewControllerAtIndex(index) } } return nil } override func viewDidLoad() { super.viewDidLoad() pageControl.numberOfPages = 3 pageControl.currentPage = 0 pageControl.tintColor = UIColor.redColor() pageControl.pageIndicatorTintColor = UIColor.blackColor() pageControl.currentPageIndicatorTintColor = UIColor.orangeColor() if let vc = storyboard?.instantiateViewControllerWithIdentifier("MyPageViewController") { self.addChildViewController(vc) self.view.addSubview(vc.view) self.view.addSubview(pageControl) pageViewController = vc as! UIPageViewController pageViewController.dataSource = self pageViewController.delegate = self pageViewController.setViewControllers([viewControllerAtIndex(0)!], direction: .Forward, animated: true, completion: nil) pageViewController.didMoveToParentViewController(self) } } } 添加为如下子视图，如何才能使页面控制行为正确？谢谢！

map[string]interface{}

Answer 1

试试这个

func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? 
{

     let identifier = viewController.restorationIdentifier

     self.index = self.identifiers.indexOfObject(identifier!)

     if index == identifiers.count - 1 {
          return nil
     }

     //increment the index to get the viewController before the current one
     self.index = self.index + 1

     return self.viewControllerAtIndex(self.index)

 }

 func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? 
 {

      let identifier = viewController.restorationIdentifier

      self.index = self.identifiers.indexOfObject(identifier!)

      if index == 0 {

           return nil
      }

      //decrement the index to get the viewController before the current one
      self.index = self.index - 1

      return self.viewControllerAtIndex(self.index)

 }

  func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int 
 {
        return self.identifiers.count
 }

  func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int 
 {
        return 0
 }