UIPageViewController delegate/datasource methods not firing

Question

I've a set up as such:

UIWindow->UIViewController->UIPageViewController->UIViewController.

I've set the delegate and datasource for the UIPageViewController to self inside the UIViewController, however every time I try to update the UIPageViewController with data, it will only display one image. I am scaling the parent UIViewController's frame up from small to large, perhaps that's affecting it? I have virtually identical code elsewhere thats not in a UIWindow and that works. Is there something about UIWindows?

Any help would be appreciated!

--EDIT--

Ok a bit more info. I'm calling this from when a user selects a table view cell. First I create a new UIWindow that's the same size as the current main UIWindow but lies on top of the status bar. Then I create an ExpandedViewController from the storyboard, set it a frame size the same as the UITableViewCell, give it some images to load into the UIPageViewController, then tell it to reload its data. I also adjust the centre of a UIImageView inside the UIPageViewController's view controller which I can animate later, but that's irrelevant. Then I add the view of the ExpandedViewController to the UIWindow. Here's that in code:

    let cell = tableView.dequeueReusableCellWithIdentifier("aCell", forIndexPath: indexPath) as! ContentTableCell

    var cellRect = tableView.rectForRowAtIndexPath(indexPath)
    var convertedFrame = tableView.convertRect(cellRect, toView: UIApplication.sharedApplication().keyWindow!)

    newWindow = UIWindow(frame: self.view.window!.bounds)
    newWindow.hidden = false
    newWindow.windowLevel = (UIWindowLevelStatusBar + 1)

    var expandedViewController = self.storyboard!.instantiateViewControllerWithIdentifier("ExpandedViewController")! as! ExpandedViewController
    expandedViewController.view.frame = convertedFrame
    expandedViewController.pageImages = imagesForTableView
    expandedViewController.reloadData(indexPath.row)

    var expandedContentViewController = (expandedViewController.pageViewController.viewControllers.last! as! ExpandedContentViewController)

    expandedContentViewController.imageView.frame = self.view.frame
    expandedContentViewController.imageView.center = CGPointMake(cellRect.width/2, cellRect.height/2 + 5)

    newWindow.backgroundColor = UIColor(red: 30/255, green: 1/255, blue: 42/255, alpha: 1)
    newWindow.addSubview(expandedViewController.view)
    newWindow.makeKeyAndVisible()

The ExpandedViewController has this code in its ViewDidLoad() method:

    self.view.clipsToBounds = true

    pageImages = []

    // Initialise the Page View Controller from storyboard. Set ourselves as delegate and datasource to it.
    pageViewController = storyboard!.instantiateViewControllerWithIdentifier("ExpandedPageViewController")! as! UIPageViewController
    pageViewController.dataSource = self
    pageViewController.delegate = self

    // Get the View Controller for the first page of the Page View Controller and store in an array
    if let startingViewController: ExpandedContentViewController = viewControllerAtIndex(0) {
        let viewControllers: NSArray = [startingViewController]
        // Set the first page of the Page View Controller
        pageViewController.setViewControllers(viewControllers as [AnyObject], direction: .Forward, animated: false, completion: nil)
    }

    // Make sure the Page View Controller takes up full area of screen
    pageViewController.view.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)

    // Add the Page View Controller to current view
    self.addChildViewController(pageViewController)
    self.view.addSubview(pageViewController.view)
    self.pageViewController.didMoveToParentViewController(self)

Answer 1

I solved it by replacing

newWindow.addSubview(expandedViewController.view)

with

newWindow.rootViewController = expandedViewController

It turns out .rootViewController is the recommended way for adding a view to a UIWindow