     // MARK: - pageviewcontroller delegate
     
     public func pageViewController(pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
+        print("pageViewController didFinishAnimating")
     }
     
     public func pageViewController(pageViewController: UIPageViewController, willTransitionToViewControllers pendingViewControllers: [UIViewController]) {
+        print("pageViewController willTransitionToViewControllers", pendingViewControllers)
     }
     
     // MARK: - pageviewcontroller datasource

    public private(set) var backgroundContentView:UIView?
    public private(set) var viewControllers:Array<UIViewController> = []
    
    private var scrollViewUpdatesEnabled:Bool = true
    public private(set) var pageViewController:UIPageViewController!
    
    public init(viewControllers:Array<UIViewController>, backgroundContentView:UIView? = nil, progressView:UIView? = nil) {
        super.init(nibName: nil, bundle: nil)

        super.viewDidLoad()
        
        if let firstViewController = self.viewControllers.first {
            self.pageViewController?.setViewControllers([firstViewController],
                direction: .Forward,
                animated: false,
                completion: nil)
