[SwiftUI] UIHostingViewController(UIKit에서 SwiftUI 사용하기)

SwiftUI의 뷰 계층에서 UIKit을 사용하기 위한 방법으로 UIViewRepresentable, UIViewControllerRepresentable 을 제공.
(https://swifty-cody.tistory.com/44)
 
반대로 UIKit 뷰 계층에서 SwiftUI를 사용하기 위한 방법으로 UIHostingViewController를 제공함.
https://developer.apple.com/documentation/swiftui/uihostingcontroller

UIHostingController | Apple Developer Documentation

 
UIHostingViewController는 SwiftUI의 View를 rootView로 주입받아서
UIViewController의 view처럼 호스팅해줌.
 
UIHostingViewController의 예시.

import UIKit
import SwiftUI

// SomeSwiftUIView를 호스팅해주는 UIHostingController
class SomeHostingViewController: UIHostingController<SomeSwiftUIView> {
    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

struct SomeSwiftUIView: View {
    var body: some View {
        VStack(alignment: .leading) {
            Text("Some SwiftUI View")
            
        }
    }
}

#Preview {
    SomeSwiftUIView()
}

 
이 UIHostingController는 UIKit 뷰 계층에서 UIViewController처럼 사용할 수 있음.
예시.

class ViewController: UIViewController {
    private let button: UIButton = {
        let button = UIButton()
        button.setTitle("SwiftUI View 띄우기", for: .normal)
        button.setTitleColor(.systemBlue, for: .normal)
        return button
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        setupView()
    }
    
    
    func setupView() {
        view.addSubview(button)
        button.addTarget(self, action: #selector(tapButton), for: .touchUpInside)
        button.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            button.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            button.centerYAnchor.constraint(equalTo: view.centerYAnchor),
        ])
    }
    
    @objc private func tapButton() {
        // SomeHostingViewController를 present
        present(SomeHostingViewController(rootView: SomeSwiftUIView()), animated: true)
    }
}