TL;DR UIPageViewController done properly.

Pageboy is a simple, highly informative page view controller.

⭐️ Features

• Simplified data source management.
• Enhanced delegation; featuring exact relative positional data and reliable updates.
• Infinite scrolling support.
• Automatic timer-based page transitioning.
• Support for custom page transitions.

📋 Requirements

Pageboy requires iOS 9 / tvOS 10 or above; and is written in Swift 4.

📲 Installation

CocoaPods

Pageboy is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'Pageboy', '~> 2.0'

And run pod install.

Carthage

Pageboy is available through Carthage. Simply install carthage with Homebrew using the following command:

$ brew update
$ brew install carthage

Add Pageboy to your Cartfile:

github "uias/Pageboy" ~> 2.0

🚀 Usage

Getting Started

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
}

3. Enjoy.

Delegation

Unfortunately, UIPageViewController doesn't provide the most useful delegate methods for detecting positional data. PageboyViewControllerDelegate provides a number of functions for being able to detect where the page view controller is, and where it's headed.

willScrollToPageAtIndex

The page view controller is about to embark on a transition to a new page.

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

didScrollToPosition

The page view controller was scrolled to a relative position along the way transitioning to a new page. Also provided is the direction of the transition.

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

didScrollToPage

The page view controller has successfully completed a scroll transition to a page.

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

didReload

The page view controller has reloaded its child view controllers.

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

⚡️ Extras

• reloadPages() - Reload the view controllers in the page view controller. (Refreshes the data source).

• scrollToPage() - Scroll the page view controller to a new page programatically.

   public func scrollToPage(_ pageIndex: PageIndex,
                              animated: Bool,
                              completion: PageTransitionCompletion? = nil)

• .navigationOrientation - Whether to orientate the pages horizontally or vertically.

• .isScrollEnabled - Whether or not scrolling is allowed on the page view controller.

• .isInfiniteScrollEnabled - Whether the page view controller should infinitely scroll at the end of page ranges.

• .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.

• .showsPageControl - Whether to show the built-in page control.

• .parentPageboy - Access the parent PageboyViewController from any child UIViewController.

  class ChildViewController: UIViewController {
  
      func doSomething() {
          parentPageboy?.scrollToPage(.next, animated: true)
      }
  }

Transitioning

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

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

The following styles are available:

• .push
• .fade
• .moveIn
• .reveal

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

Auto Scrolling

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.

👨🏻‍💻 About

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

❤️ Contributing

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

👮🏻‍♂️ License

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