Simple UIPageViewController Bridge

PageView.swift

import SwiftUI
import UIKit

// Add refinements to this official practice:
// https://developer.apple.com/tutorials/swiftui/interfacing-with-uikit
struct PageView<Page : View> : View {
    
    var pages: () -> [Page]
    
    @State private var currentIndex: Int = 0

    init(@PagesBuilder<Page> pages: @escaping () -> [Page]) {
        self.pages = pages
    }
    
    var body: some View {
        ZStack {
            PageViewController(currentIndex: $currentIndex, pages: pages).ignoresSafeArea(edges: .bottom)
            VStack {
                Spacer()
                PageControl(numberOfPages: pages().count, currentPage: $currentIndex)
            }
        }
    }

}

@resultBuilder
struct PagesBuilder<Page : View> {
    public static func buildBlock(_ components: Page...) -> [Page] {
        components
    }
}

struct PageViewController<Page : View> : UIViewControllerRepresentable {
    
    var pages: () -> [Page]
    
    @Binding var currentIndex: Int
    
    init(currentIndex: Binding<Int>, @PagesBuilder<Page> pages: @escaping () -> [Page]) {
        self._currentIndex = currentIndex
        self.pages = pages
    }
        
    func makeUIViewController(context: Context) -> UIPageViewController {
        let viewController = UIPageViewController(transitionStyle: .scroll, navigationOrientation: .horizontal)
        viewController.dataSource = context.coordinator
        viewController.delegate = context.coordinator
        return viewController
    }
    
    func updateUIViewController(_ uiViewController: UIPageViewController, context: Context) {
        uiViewController.setViewControllers([context.coordinator.controllers[currentIndex]], direction: .forward, animated: false)
    }
    
    func makeCoordinator() -> Coordinator {
        return Coordinator(parent: self)
    }
    
    class Coordinator: NSObject, UIPageViewControllerDelegate, UIPageViewControllerDataSource {
        
        var parent: PageViewController
        var controllers: [UIViewController] = []
        
        init(parent: PageViewController) {
            self.parent = parent
            self.controllers = parent.pages().map({ UIHostingController(rootView: $0) })
        }
                
        func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
            
            guard let index = controllers.firstIndex(of: viewController), index != 0 else {
                return nil
            }
            
            return controllers[index - 1]
        }
        
        func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
            
            guard let index = controllers.firstIndex(of: viewController), index != (controllers.endIndex - 1) else {
                return nil
            }
            
            return controllers[index + 1]
        }
        
        func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
            if completed,
               let visibleViewController = pageViewController.viewControllers?.first,
               let index = controllers.firstIndex(of: visibleViewController) {
                parent.currentIndex = index
            }

        }
        
    }
    
    
}

struct PageControl: UIViewRepresentable {
    
    var numberOfPages: Int
    @Binding var currentPage: Int

    func makeUIView(context: Context) -> UIPageControl {
        let control = UIPageControl()
        control.numberOfPages = numberOfPages
        control.backgroundStyle = .prominent
        control.addTarget(context.coordinator, action: #selector(Coordinator.updateCurrentPage(_:)), for: .valueChanged)

        return control
    }

    func updateUIView(_ uiView: UIPageControl, context: Context) {
        uiView.currentPage = currentPage
    }
    
    func makeCoordinator() -> Coordinator {
        return Coordinator(parent: self)
    }
    
    class Coordinator: NSObject {
        
        var parent: PageControl
        
        init(parent: PageControl) {
            self.parent = parent
        }
        
        @MainActor @objc func updateCurrentPage(_ sender: UIPageControl) {
            self.parent.currentPage = sender.currentPage
        }
        
    }
    
}