PageViewController.swift


  1. import SwiftUI
  2. import UIKit
  4. struct PageViewController<Page: View>: UIViewControllerRepresentable {
  5. var pages: [Page]
  6. @Binding var currentPage: Int
  8. func makeCoordinator() -> Coordinator {
  9. Coordinator(self)
  10. }
  12. func makeUIViewController(context: Context) -> UIPageViewController {
  13. let pageViewController = UIPageViewController(
  14. transitionStyle: .scroll,
  15. navigationOrientation: .horizontal)
  16. pageViewController.dataSource = context.coordinator
  17. pageViewController.delegate = context.coordinator
  19. return pageViewController
  20. }
  22. func updateUIViewController(_ pageViewController: UIPageViewController, context: Context) {
  23. pageViewController.setViewControllers(
  24. [context.coordinator.controllers[currentPage]], direction: .forward, animated: true)
  25. }
  27. class Coordinator: NSObject, UIPageViewControllerDataSource, UIPageViewControllerDelegate {
  28. var parent: PageViewController
  29. var controllers = [UIViewController]()
  31. init(_ pageViewController: PageViewController) {
  32. parent = pageViewController
  33. controllers = parent.pages.map { UIHostingController(rootView: $0) }
  34. }
  36. func pageViewController(
  37. _ pageViewController: UIPageViewController,
  38. viewControllerBefore viewController: UIViewController) -> UIViewController?
  39. {
  40. guard let index = controllers.firstIndex(of: viewController) else {
  41. return nil
  42. }
  43. if index == 0 {
  44. return controllers.last
  45. }
  46. return controllers[index - 1]
  47. }
  49. func pageViewController(
  50. _ pageViewController: UIPageViewController,
  51. viewControllerAfter viewController: UIViewController) -> UIViewController?
  52. {
  53. guard let index = controllers.firstIndex(of: viewController) else {
  54. return nil
  55. }
  56. if index + 1 == controllers.count {
  57. return controllers.first
  58. }
  59. return controllers[index + 1]
  60. }
  62. func pageViewController(
  63. _ pageViewController: UIPageViewController,
  64. didFinishAnimating finished: Bool,
  65. previousViewControllers: [UIViewController],
  66. transitionCompleted completed: Bool) {
  67. if completed,
  68. let visibleViewController = pageViewController.viewControllers?.first,
  69. let index = controllers.firstIndex(of: visibleViewController) {
  70. parent.currentPage = index
  71. }
  72. }
  73. }
  74. }