我正在创建pageViewController内部createViewController()方法。我定义了UIPageViewController的一个属性self.pageController。
由于重复的代码块，当这些页面打开时，当我们离开滚动页面时，它也会显示在视图后面。
func createPageController()
{
var deviceFrame:CGSize = UIScreen.mainScreen().bounds.size
self.pageController = UIPageViewController(transitionStyle: UIPageViewControllerTransitionStyle.Scroll,
navigationOrientation: UIPageViewControllerNavigationOrientation.Horizontal,
options: [UIPageViewControllerOptionInterPageSpacingKey : 0])
self.pageController!.view.frame = CGRectMake(0,108, deviceFrame.width, deviceFrame.height-110)
self.dailyChallengeViewController = UIStoryboard(name: "Main_iPhone", bundle: nil).instantiateViewControllerWithIdentifier("DailyChallengeViewController") as? DailyChallengeViewController
self.winnersViewController = UIStoryboard(name: "Main_iPhone", bundle: nil).instantiateViewControllerWithIdentifier("WinnersViewController") as? WinnersViewController
// All the below code will repeat 1 more time
self.winnersViewController!.view.frame = self.pageController!.view.frame
self.dailyChallengeViewController!.view.frame = self.pageController!.view.frame
self.dailyChallengeViewController!.index = 0
self.winnersViewController!.index = 1
self.viewControllers = [self.dailyChallengeViewController!,self.winnersViewController!]
self.pageController!.setViewControllers([self.dailyChallengeViewController!],
direction:UIPageViewControllerNavigationDirection.Forward,
animated:false,
completion:nil)
self.addChildViewController(self.pageController!)
self.view.addSubview(self.pageController!.view)
self.pageController!.dataSource = self
self.pageController!.delegate = self
self.pageController!.didMoveToParentViewController(self)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController?{
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController?{
}
最佳答案
据我所知，很多人都有这个问题。
这是因为viewControllerBeforeViewController和viewControllerAfterViewController。
建议使用willTransitionToViewControllers来获取PVC的当前索引以及上述的其他两种方法。
换句话说，如果希望在索引x处发生特定的事情，请在willTransitionToViewControllers委托方法中编写if语句。
希望这对你有帮助！
PageViewController delegate functions called twice
关于ios - 为什么PageViewController中的代码发生两次？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/27152997/