TutorialViewController.swift
import UIKit
class TutorialViewController: UIViewController {
@IBOutlet weak var pageControl: UIPageControl!
@IBOutlet weak var containerView: UIView!
var tutorialPageViewController: TutorialPageViewController? {
didSet {
tutorialPageViewController?.tutorialDelegate = self
}
}
override func viewDidLoad() {
super.viewDidLoad()
pageControl.addTarget(self, action: #selector(TutorialViewController.didChangePageControlValue), for: .valueChanged)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let tutorialPageViewController = segue.destination as? TutorialPageViewController {
self.tutorialPageViewController = tutorialPageViewController
}
}
@IBAction func didTapNextButton(_ sender: UIButton) {
tutorialPageViewController?.scrollToNextViewController()
}
/**
Fired when the user taps on the pageControl to change its current page.
*/
func didChangePageControlValue() {
tutorialPageViewController?.scrollToViewController(index: pageControl.currentPage)
}
}
extension TutorialViewController: TutorialPageViewControllerDelegate {
func tutorialPageViewController(_ tutorialPageViewController: TutorialPageViewController,
didUpdatePageCount count: Int) {
pageControl.numberOfPages = count
}
func tutorialPageViewController(_ tutorialPageViewController: TutorialPageViewController,
didUpdatePageIndex index: Int) {
pageControl.currentPage = index
}
}
TutorialPageViewController.swift
import UIKit
class TutorialPageViewController: UIPageViewController {
weak var tutorialDelegate: TutorialPageViewControllerDelegate?
fileprivate(set) lazy var orderedViewControllers: [UIViewController] = {
// The view controllers will be shown in this order
return [self.newColoredViewController(“Green”),
self.newColoredViewController(“Red”),
self.newColoredViewController(“Blue”)]
}()
override func viewDidLoad() {
super.viewDidLoad()
dataSource = self
delegate = self
if let initialViewController = orderedViewControllers.first {
scrollToViewController(initialViewController)
}
tutorialDelegate?.tutorialPageViewController(self,
didUpdatePageCount: orderedViewControllers.count)
}
/**
Scrolls to the next view controller.
*/
func scrollToNextViewController() {
if let visibleViewController = viewControllers?.first,
let nextViewController = pageViewController(self,
viewControllerAfter: visibleViewController) {
scrollToViewController(nextViewController)
}
}
/**
Scrolls to the view controller at the given index. Automatically calculates
the direction.
– parameter newIndex: the new index to scroll to
*/
func scrollToViewController(index newIndex: Int) {
if let firstViewController = viewControllers?.first,
let currentIndex = orderedViewControllers.index(of: firstViewController) {
let direction: UIPageViewControllerNavigationDirection = newIndex >= currentIndex ? .forward : .reverse
let nextViewController = orderedViewControllers[newIndex]
scrollToViewController(nextViewController, direction: direction)
}
}
fileprivate func newColoredViewController(_ color: String) -> UIViewController {
return UIStoryboard(name: “Main”, bundle: nil) .
instantiateViewController(withIdentifier: “\(color)ViewController”)
}
/**
Scrolls to the given ‘viewController’ page.
– parameter viewController: the view controller to show.
*/
fileprivate func scrollToViewController(_ viewController: UIViewController,
direction: UIPageViewControllerNavigationDirection = .forward) {
setViewControllers([viewController],
direction: direction,
animated: true,
completion: { (finished) -> Void in
// Setting the view controller programmatically does not fire
// any delegate methods, so we have to manually notify the
// ‘tutorialDelegate’ of the new index.
self.notifyTutorialDelegateOfNewIndex()
})
}
/**
Notifies ‘_tutorialDelegate’ that the current page index was updated.
*/
fileprivate func notifyTutorialDelegateOfNewIndex() {
if let firstViewController = viewControllers?.first,
let index = orderedViewControllers.index(of: firstViewController) {
tutorialDelegate?.tutorialPageViewController(self,
didUpdatePageIndex: index)
}
}
}
// MARK: UIPageViewControllerDataSource
extension TutorialPageViewController: UIPageViewControllerDataSource {
func pageViewController(_ pageViewController: UIPageViewController,
viewControllerBefore viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.index(of: viewController) else {
return nil
}
let previousIndex = viewControllerIndex – 1
// User is on the first view controller and swiped left to loop to
// the last view controller.
guard previousIndex >= 0 else {
return orderedViewControllers.last
}
guard orderedViewControllers.count > previousIndex else {
return nil
}
return orderedViewControllers[previousIndex]
}
func pageViewController(_ pageViewController: UIPageViewController,
viewControllerAfter viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.index(of: viewController) else {
return nil
}
let nextIndex = viewControllerIndex + 1
let orderedViewControllersCount = orderedViewControllers.count
// User is on the last view controller and swiped right to loop to
// the first view controller.
guard orderedViewControllersCount != nextIndex else {
return orderedViewControllers.first
}
guard orderedViewControllersCount > nextIndex else {
return nil
}
return orderedViewControllers[nextIndex]
}
}
extension TutorialPageViewController: UIPageViewControllerDelegate {
func pageViewController(_ pageViewController: UIPageViewController,
didFinishAnimating finished: Bool,
previousViewControllers: [UIViewController],
transitionCompleted completed: Bool) {
notifyTutorialDelegateOfNewIndex()
}
}
protocol TutorialPageViewControllerDelegate: class {
/**
Called when the number of pages is updated.
– parameter tutorialPageViewController: the TutorialPageViewController instance
– parameter count: the total number of pages.
*/
func tutorialPageViewController(_ tutorialPageViewController: TutorialPageViewController,
didUpdatePageCount count: Int)
/**
Called when the current index is updated.
– parameter tutorialPageViewController: the TutorialPageViewController instance
– parameter index: the index of the currently visible page.
*/
func tutorialPageViewController(_ tutorialPageViewController: TutorialPageViewController,
didUpdatePageIndex index: Int)
}
iOS Development Swift 