Ios 以编程方式更改UIPageViewController页面

我使用的UIPageViewController具有“下一步”按钮，其功能与“滑动到下一个视图”相同

@IBAction func next(sender: UIButton!) {

    let pageContentViewController = pageViewController.viewControllers![0] as! WelcomeViewController
    let index = pageContentViewController.pageIndex + 1

    if index < titleArray.count {
        let vctoMove = self.viewControllerAtIndex(index) as WelcomeViewController
        let viewControllers = NSArray(objects: vctoMove)
        pageViewController.setViewControllers(viewControllers as? [UIViewController], direction: .Forward, animated: true, completion: nil)
    }
}

@IBAction func next（发送方：UIButton！）{
让pageContentViewController=pageViewController.ViewController！[0]作为！WelcomeViewController
让index=pageContentViewController.pageIndex+1
如果索引

它不工作吗？它更改视图但页面控制指示器不更新它不工作吗？它更改视图但页面控制指示器不更新