UIKitAndSwiftUIDataFlow.swift

import UIKit
import SwiftUI

final class LoginViewController: UIHostingController<LoginView> {
    private let viewModel: LoginViewModel
    
    init(viewModel: LoginViewModel) {
        self.viewModel = viewModel
        super.init(rootView: LoginView(viewModel: viewModel))
    }
    
    @MainActor @objc required dynamic init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    private func changeNameBarItemDidTap() {
        viewModel.userName = "Christian"
    }
}

final class LoginViewModel: ObservableObject {
    @Published var userName = "Luis"
}

struct LoginView: View {
    @ObservedObject var viewModel: LoginViewModel

    var body: some View {
        Text(viewModel.userName)
    }
}