SwiftUI View to UIView

Example.swift

import UIKit
import SwiftUI

// SwiftUI
struct SomeView: View, HostingViewInitialization {
  
    var body: some View { 
        Text("Hello World!") 
    }
}

// UIKit
class RootViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // SwiftUI View -> UIView
        let uiView = HostingView<SomeView>()
    }
}

HostingView.swift

import UIKit
import SwiftUI

protocol HostingViewInitialization {
    init()
}

class HostingView<T: View & HostingViewInitialization>: UIView {

    private(set) var hostingController: UIHostingController<T>!

    var rootView: T {
        get { hostingController.rootView }
        set { hostingController.rootView = newValue }
    }
  
    override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setup()
    }
}

// MARK: - Private

private extension HostingView {

    func setup() {
        backgroundColor = .clear
        hostingController = UIHostingController(rootView: T.init())
        hostingController.view.backgroundColor = backgroundColor
        hostingController.view.frame = self.bounds
        hostingController.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]

        addSubview(hostingController.view)
    }
}