在UIPageViewController中以编程方式转到下一页

// 获取当前UIPageViewController实例
guard let pageViewController = self.pageViewController else {
    return
}

// 获取当前显示的页面索引
guard let currentViewController = pageViewController.viewControllers?.first,
      let currentIndex = orderedViewControllers.firstIndex(of: currentViewController) else {
    return
}

// 计算下一页的索引
let nextIndex = currentIndex + 1

// 检查下一页的索引是否超出范围
guard nextIndex < orderedViewControllers.count else {
    return
}

// 创建下一页的视图控制器实例
let nextViewController = orderedViewControllers[nextIndex]

// 设置下一页的视图控制器为当前显示的视图控制器
pageViewController.setViewControllers([nextViewController], direction: .forward, animated: true, completion: nil)