UIPageViewController doesn't stop scroll - ios

Question

I am Using UIPageController having 2 images in it. While running the app, The UIPageController shows the first page perfectly, but then scrolls infinitely from the second page. It maintains the same image and continues to show the similar image even after it has reached the limit. It only changes the image for the first swipe, and then neither changes the image nor revert back to the initial image on the subsequent scroll.
Given is the source. Please help.
import UIKit
class SignUpViewController: UIViewController, UIPageViewControllerDataSource {
var pageViewController : UIPageViewController!
var InfoImages : NSArray!
override func viewDidLoad() {
super.viewDidLoad()
self.InfoImages = NSArray(objects: "blue","red")
self.pageViewController = self.storyboard?.instantiateViewControllerWithIdentifier("IntroPageController") as! UIPageViewController
self.pageViewController.dataSource = self
let startVC = self.viewControllerAtIndex(0) as ContentViewController
let viewControllers = NSArray(object: startVC)
self.pageViewController.setViewControllers(viewControllers as? [UIViewController], direction: .Forward, animated: true, completion: nil)
self.pageViewController.view.frame = CGRectMake(0, 0, self.view.frame.width, self.view.frame.height)
self.addChildViewController(self.pageViewController)
self.view.addSubview(self.pageViewController.view)
self.pageViewController.didMoveToParentViewController(self)
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func viewControllerAtIndex(index: Int) -> ContentViewController
{
if ((self.InfoImages.count == 0) || (index >= self.InfoImages.count)){
return ContentViewController()
}
let info = storyBoard.instantiateViewControllerWithIdentifier("ContentViewController") as! ContentViewController
info.imageFile = self.InfoImages[index] as! String
return info
}
//MARK : -DataSource
func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController?
{
let vc = viewController as! ContentViewController
var index = vc.pageIndex as Int
if( index == 0 || index == NSNotFound ){
return nil
}
index--
return self.viewControllerAtIndex(index)
}
func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController?
{
let vc = viewController as! ContentViewController
var index = vc.pageIndex as Int
if( index == NSNotFound ){
return nil
}
index++
if(index == self.InfoImages.count){
return nil
}
return self.viewControllerAtIndex(index)
}
#available(iOS 6.0, *)
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int
{
return self.InfoImages.count
}
#available(iOS 6.0, *)
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int
{
return 0
}
#IBAction func SkipInfo(sender: AnyObject) {
let skipinfo = storyBoard.instantiateViewControllerWithIdentifier("afterLoginview") as! LoginViewController
self.presentViewController(skipinfo , animated: true, completion: nil)
}
Cheers and Thanks in advance!
P.S : I am using Xcode 7.0 beta (swift 2.0)