UIKit.swift

class ViewController: UIViewController {
   override func viewDidLoad() {
     super.viewDidLoad()
     let swiftUIView = UIHostingController(rootView: SwiftUIView())
      swiftUIView.view.translatesAutoresizingMaskIntoConstraints = false
      self.addSubview(swiftUIView.view)
        
        swiftUIView.view.layout {
            $0.top == self.view.topAnchor
            $0.leading == self.view.leadingAnchor
            $0.trailing == self.view.trailingAnchor
            $0.bottom == self.view.bottomAnchor
        }
     
   }
}