UIkit과 SwiftUI이용하여 Scroll Paging 구현하기

[뷰 설명]

StackView: Text와 ContentView를 묶어주는 뷰

ViewController: UiKit -> 실제 페이지 올라가는 뷰

ContentView: currentPage 값만 받아옴. UIKit을 SwiftUI로 변환

                         Coordinator가 존재하여 페이지 넘김이 이루어졌을 때, UIScrollViewDelegate를 채택.

StackView

import SwiftUI

struct StackView: View {
    @State var currentPage: Int = 0
    
    var body: some View {
        ZStack{
            ContentView(currentPage: $currentPage)
            Text("\(currentPage)").foregroundStyle(.white)
            
        }
    }
}

ViewController

import UIKit
import SwiftUI

class ViewController: UIViewController {

    let scrollView = UIScrollView()
    let numberOfPages = 3
    let pageWidth: CGFloat = UIScreen.main.bounds.width
    let pageHeight: CGFloat = UIScreen.main.bounds.height

    var currentPage = 0
    var currentPageBinding: Binding<Int>?

    override func viewDidLoad() {
        super.viewDidLoad()

        scrollView.frame = CGRect(x: 0, y: 0, width: pageWidth, height: pageHeight)
        scrollView.isPagingEnabled = true
        scrollView.contentSize = CGSize(width: pageWidth * CGFloat(numberOfPages), height: pageHeight)
        scrollView.delegate = self
        view.addSubview(scrollView)

        for i in 0..<numberOfPages {
            let imageView = UIImageView()
            imageView.contentMode = .scaleAspectFit
            imageView.clipsToBounds = true
            imageView.frame = CGRect(x: pageWidth * CGFloat(i), y: 0, width: pageWidth, height: pageHeight)
            imageView.image = UIImage(named: "image\(i+1)") // 이미지 이름에 따라 변경해주세요.
            scrollView.addSubview(imageView)
        }
    }
    
}

extension ViewController: UIScrollViewDelegate {
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        let contentOffsetX = scrollView.contentOffset.x
        let page = Int(contentOffsetX / pageWidth)
        currentPage = page
        
        currentPageBinding?.wrappedValue = currentPage

    }
}

ContentView

import SwiftUI

struct ContentView: UIViewControllerRepresentable {
    @Binding var currentPage: Int 
    
    func makeUIViewController(context: Context) -> ViewController {
           let viewController = ViewController()
           viewController.currentPageBinding = $currentPage
           return viewController
       }

    func updateUIViewController(_ uiViewController: ViewController, context: Context) {

    }
    
    class Coordinator: NSObject, UIScrollViewDelegate {
            var parent: ContentView

            init(parent: ContentView) {
                self.parent = parent
            }

            func scrollViewDidScroll(_ scrollView: UIScrollView) {
                let contentOffsetX = scrollView.contentOffset.x
                let page = Int(contentOffsetX / scrollView.frame.size.width)
                parent.currentPage = page
            }
        }

        func makeCoordinator() -> Coordinator {
            return Coordinator(parent: self)
        }
}

#Preview {
        ContentView(currentPage: .constant(0))
}