Page Indicator out of sync swift - ios

Question

I have the following PageViewController class :
class ProjectorPageViewController : UIPageViewController, UIPageViewControllerDataSource {
var randUsed : [String]?
var pageViewMatches : [SingleMatch]? {
didSet {
//irrelevant code
}
let initialcontroller = viewControlerAtIndex(0)
let viewControllers = [initialcontroller!]
setViewControllers(viewControllers, direction: .Forward, animated: true, completion: nil)
}
}
override func viewDidLoad() {
super.viewDidLoad()
dataSource = self
let pageControl = UIPageControl.appearance()
pageControl.currentPageIndicatorTintColor = UIColor.whiteColor()
pageControl.pageIndicatorTintColor = UIColor(red: (69/255.0), green: (209/255.0), blue: (153/255.0), alpha: 1.0)
}
func viewControlerAtIndex(index : Int) -> PageViewContentViewController? {
if (self.pageUsers!.count == 0 || index >= self.pageUsers!.count) {
return nil
}
let controller = PageViewContentViewController()
controller.location = pageLocations![index]
controller.image_name = pageImages![index]
controller.user_name = pageUsers![index]
controller.pageIndex = index
return controller
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
let curr_index = (viewController as! PageViewContentViewController).pageIndex
print ("attempting after with index : " + String(curr_index))
if (curr_index! < pageViewMatches!.count - 1) {
return viewControlerAtIndex(curr_index! + 1) }
else {
return nil
}
}
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
let curr_index = (viewController as! PageViewContentViewController).pageIndex
print ("attempting before with index : " + String(curr_index))
if (curr_index! > 0 ) {
return viewControlerAtIndex(curr_index! - 1)
}
else {
return nil
}
}
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int {
if let matches = pageViewMatches {
return matches.count
}
else {
return 0
}
}
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int {
return pageViewController.viewControllers!.indexOf((pageViewController.viewControllers?.first)!)!
}
}
The problem is that if I swipe fast enough between the pages, the page indicator becomes out of sync, and points to the wrong page. If I swipe at a moderate pace this doesn't occur. I have seen a similar post which said the solution was to implement the presentationIndexForPageViewController method, however translating this from Objective-C (unless I made a mistake in translation) did not solve the problem. Here is the post I am referring to : UIPageViewController setViewControllers, UIPageControl not showing right current number

Answer 1

func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int {
let vc = pageViewController.viewControllers!.first as! PageViewContentViewController
return vc.pageIndex
}
You must return pageIndex... pageViewController.viewControllers!.indexOf((pageViewController.viewControllers?.first)!)! won't return right index