TL;DR UIPageViewController done properly.

• Simplified data source management & enhanced delegation.
• Dynamically insert & remove pages.
• Infinite scrolling support.
• Automatic timer-based page transitioning.
• Support for custom animated page transitions.

Pageboy requires iOS 12 / tvOS 12; and is compatible with Swift 5.

Pageboy is compatible with Swift Package Manager and can be integrated via Xcode.

Pageboy is also available through CocoaPods:

pod 'Pageboy', '~> 4.2'

Pageboy is also available through Carthage:

github "uias/Pageboy" ~> 4.2

• The Basics
• PageboyViewControllerDelegate
• Navigation
• Insertion & Deletion

1. Create an instance of a PageboyViewController and provide it with a PageboyViewControllerDataSource.

class PageViewController: PageboyViewController, PageboyViewControllerDataSource {

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

2. Implement the PageboyViewControllerDataSource functions.

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
}

The delegate functions provided by a PageboyViewController are much more reliable and useful than what a raw UIPageViewController provides. You can use them to find out exactly where the current page is, and when it's moved, where it's headed.

About to embark on a transition to a new page.

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

Scrolled to a relative position along the way transitioning to a new page.

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

Successfully completed a scroll transition to a page.

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

Child view controllers have been reloaded.

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

You can navigate programmatically through a PageboyViewController using scrollToPage():

pageViewController.scrollToPage(.next, animated: true)

• Infinite scrolling can be enabled with .isInfiniteScrollEnabled.
• Interactive scrolling can also be controlled with .isScrollEnabled.

Pageboy provides the ability to insert and delete pages dynamically in the PageboyViewController.

func insertPage(at index: PageIndex, then updateBehavior: PageUpdateBehavior)
func deletePage(at index: PageIndex, then updateBehavior: PageUpdateBehavior)

This behaves similarly to the insertion of rows in UITableView, in the fact that you have to update the data source prior to calling any of the update functions.

Example:

let index = 2
viewControllers.insert(UIViewController(), at: index)
pageViewController.insertPage(at: index)

The default behavior after inserting or deleting a page is to scroll to the update location, this however can be configured by passing a PageUpdateBehavior value other than .scrollToUpdate.

• reloadData() - Reload the view controllers in the page view controller. (Reloads the data source).
• .navigationOrientation - Whether to orientate the pages horizontally or vertically.
• .currentViewController - The currently visible view controller if it exists.
• .currentPosition - The exact current relative position of the page view controller.
• .currentIndex - The index of the currently visible page.
• .parentPageboy - Access the immediate parent PageboyViewController from any child view controller.

Pageboy also provides custom transition support for animated transitions. This can be customized via the .transition property on PageboyViewController.

pageboyViewController.transition = Transition(style: .push, duration: 1.0)

Note: By default this is set to nil, which uses the standard animation provided by UIPageViewController.

PageboyAutoScroller is available to set up timer based automatic scrolling of the PageboyViewController:

pageboyViewController.autoScroller.enable()

Support for custom intermission duration and other scroll behaviors is also available.

• Created by Merrick Sapsford (@MerrickSapsford)
• Contributed to by a growing list of others.

Bug reports and pull requests are welcome on GitHub at https://github.com/uias/Pageboy.

The library is available as open source under the terms of the MIT License.