ios - swift:向前和向后翻转 Action

Question

我有UIPageViewController。我想通过单击按钮来翻转页面。我想像 viewControllerAfter 和 viewControllerBefore 一样向前和向后翻转页面。我使用此代码来翻页，但它不起作用:

@IBAction func nextAction(_ sender: Any) {

    let pageController = self.storyboard?.instantiateViewController(withIdentifier: "PageViewController") as! UIPageViewController

    pageController.dataSource = self
    pageController.delegate = self

    let firstController = getContentViewController(withIndex: 0)!
    let secondController = getContentViewController(withIndex: 1)!
    let contentControllers = [firstController, secondController]

    pageController.setViewControllers(contentControllers, direction: .forward, animated: true, completion: nil)
}

如何解决？

更新

extension UIPageViewController {

    func goToNextPage(animated: Bool = true) {
        guard let currentViewController = self.viewControllers?.first else { return }
        guard let nextViewController = dataSource?.pageViewController(self, viewControllerAfter: currentViewController) else { return }
        setViewControllers([nextViewController], direction: .forward, animated: animated, completion: nil)
    }

    func goToPreviousPage(animated: Bool = true) {
        guard let currentViewController = self.viewControllers?.first else { return }
        guard let previousViewController = dataSource?.pageViewController(self, viewControllerBefore: currentViewController) else { return }
        setViewControllers([previousViewController], direction: .reverse, animated: animated, completion: nil)
    }

}

Answer 1

首先，您必须有一个事件的 pageVC 才能导航到特定的 VC ，而不是

pageController.setViewControllers(contentControllers, direction: .forward, animated: true, completion: nil)

您必须仅设置要导航到的 vc

pageController.setViewControllers([firstController], direction: .forward, animated: true, completion: nil)

并跟踪它的索引，因此当用户再次滚动时，将调用 dataSource 方法来加载正确的 VC ，我创建了一个演示 Here做同样的工作