FullScreenPresenter modifier

FullScreenPresenter.swift

import SwiftUI
import UIKit

struct FullScreenPresenter<Overlay: View>: UIViewControllerRepresentable {
  @Binding var isPresented: Bool
  let overlay: () -> Overlay

  func makeUIViewController(context: Context) -> UIViewController {
    UIViewController() // container
  }

  func updateUIViewController(_ host: UIViewController, context: Context) {
    if isPresented && context.coordinator.presented == nil {
      let vc = UIHostingController(rootView: overlay())
      vc.modalPresentationStyle = .overFullScreen
      vc.modalTransitionStyle = .crossDissolve
      context.coordinator.presented = vc
      host.present(vc, animated: true)
    }
    else if !isPresented, let vc = context.coordinator.presented {
      vc.dismiss(animated: true) {
        context.coordinator.presented = nil
      }
    }
  }

  func makeCoordinator() -> Coordinator { Coordinator() }
  class Coordinator { var presented: UIViewController? }
}

extension View {
  /// Usage: .fullScreenOverlay(isPresented: $show) { MyOverlay() }
  func fullScreenOverlay<Overlay: View>(
    isPresented: Binding<Bool>,
    @ViewBuilder _ overlay: @escaping () -> Overlay
  ) -> some View {
    background( // attach it anywhere
      FullScreenPresenter(isPresented: isPresented, overlay: overlay)
        .frame(width: 0, height: 0)
    )
  }
}