Pageboy

To use Pageboy, create a subclass of PageboyViewController and assign it a PageboyViewControllerDataSource. You must implement the following three methods to provide your view controllers:

1. numberOfViewControllers(in:): Returns the total count of pages.
2. viewController(for:at:): Returns the specific UIViewController for a given PageIndex.
3. defaultPage(for:): Returns an optional Page to serve as the default page (can return nil).

class PageViewController: PageboyViewController, PageboyViewControllerDataSource {

    override func viewDidLoad() {
        super.viewDidLoad()
	self.dataSource = self
    }
}

// Implementation of PageboyViewControllerDataSource
func numberOfViewControllers(in pageboyViewController: PageboyViewController) -> Int {
    return viewControllers.count
}

func viewController(for pageboyViewController: PageboyViewController,
                    at index: PageboyViewController.PageIndex) -> UIViewController? {
    return viewControllers[index]
}

func defaultPage(for pageboyViewController: PageboyViewController) -> PageboyViewController.Page? {
    return nil
}

In Pageboy 2.0, PageboyViewControllerDataSource has been redesigned to support dynamic view controller loading and better performance. Instead of returning a static array of view controllers, you must now implement methods to provide the page count and fetch specific view controllers by index.

Key changes:

• Replace viewControllers(forPageboyViewController:) with a combination of numberOfViewControllers(in:) and viewController(for:at:).
• Update defaultPageIndex(forPageboyViewController:) to defaultPage(for:).
• Use PageboyViewController.PageIndex (an Int typealias) for index values.

// Pageboy 2.x implementation
func numberOfViewControllers(in pageboyViewController: PageboyViewController) -> PageboyViewController.PageIndex {
    return 2
}
    
func viewController(for pageboyViewController: PageboyViewController,
                    at index: PageboyViewController.PageIndex) -> UIViewController? {
    return self.viewControllers[index]
}

func defaultPage(for pageboyViewController: PageboyViewController) -> PageboyViewController.Page? {
    return nil
}

The PageboyViewControllerDelegate methods have been refactored to support the new data source and updated syntax. When migrating, ensure you update the method signatures for scrolling and reloading events.

Signature updates:

• willScrollToPageAt: Uses PageboyViewController.PageIndex instead of Int.
• didScrollTo: Now includes an animated: Bool parameter.
• didScrollToPageAt: Uses PageboyViewController.PageIndex instead of Int and includes animated: Bool.
• didReloadWith: Replaces didReload to provide the currentViewController and currentPageIndex instead of an array of view controllers.

// Pageboy 2.x Delegate Examples

func pageboyViewController(_ pageboyViewController: PageboyViewController,
                            willScrollToPageAt index: PageboyViewController.PageIndex,
                            direction: PageboyViewController.NavigationDirection,
                            animated: Bool)

func pageboyViewController(_ pageboyViewController: PageboyViewController,
                            didScrollTo position: CGPoint,
                            direction: PageboyViewController.NavigationDirection,
                            animated: Bool)

func pageboyViewController(_ pageboyViewController: PageboyViewController,
                            didScrollToPageAt index: PageboyViewController.PageIndex,
                            direction: PageboyViewController.NavigationDirection,
                            animated: Bool)

func pageboyViewController(_ pageboyViewController: PageboyViewController,
                            didReloadWith currentViewController: UIViewController,
                            currentPageIndex: PageboyViewController.PageIndex)