SwiftUIRepresentable.swift

import SwiftUI
import Combine

struct MyContentView: View {
    @State var isPresentingModal = false

    // comment this out
     @Environment(\.presentationMode) var presentationMode: Binding<PresentationMode>

    var body: some View {
        VStack {
            Button("Show modal") {
                isPresentingModal = true
            }
            .padding()
        }
        .sheet(isPresented: $isPresentingModal) {
            MyModalView(viewModel: TempViewModel())
        }
        .navigationBarTitle("Details")
    }
}

class TempViewModel: ObservableObject {
    @Published var sliderText = ""
    @Published var sliderValue: Double = 0
    private var cancellable = Set<AnyCancellable>()

    init() {
        $sliderValue
            .print("view model")
            .sink { [weak self] value in
                self?.sliderText = "\(value) C = \(String(format: "%.2f" ,value * 9 / 5 + 32)) F"
            }
            .store(in: &cancellable)
    }
}

struct MyModalView: View {
    @ObservedObject var viewModel: TempViewModel

    var body: some View {
        VStack(alignment: .leading) {
            Text("SwiftUI Slider")
            Slider(value: $viewModel.sliderValue, in: -100...100, step: 0.5)
                .padding(.bottom)

            Text("UIViewRepresentable Slider")
            SwiftUISlider(minValue: -100, maxValue: 100, value: $viewModel.sliderValue)
            Text(viewModel.sliderText)
        }
        .padding()
    }
}

struct SwiftUISlider: UIViewRepresentable {
    final class Coordinator: NSObject {
        @Binding var value: Double
        init(value: Binding<Double>) {
            _value = value
        }

        @objc func valueChanged(_ sender: UISlider) {
            let index = Int(sender.value + 0.5)
            sender.value = Float(index)
            print("value changed \(sender.value)")
            self.value = Double(sender.value)
        }
    }

    var minValue: Int = 0
    var maxValue: Int = 0

    @Binding var value: Double

    func makeUIView(context: Context) -> UISlider {
        let slider = UISlider(frame: .zero)
        adapt(slider, context: context)
        return slider
    }

    func updateUIView(_ uiView: UISlider, context: Context) {
        adapt(uiView, context: context)
    }

    func makeCoordinator() -> SwiftUISlider.Coordinator {
        Coordinator(value: $value)
    }

    private func adapt(_ slider: UISlider, context: Context) {
        slider.minimumTrackTintColor = .systemRed
        slider.maximumTrackTintColor = .systemRed
        slider.maximumValue = Float(maxValue)
        slider.minimumValue = Float(minValue)
        slider.value = Float(value)

        slider.addTarget(
            context.coordinator,
            action: #selector(Coordinator.valueChanged(_:)),
            for: .valueChanged
        )
    }
}

struct PresentationMode_Previews: PreviewProvider {
    static var previews: some View {
        MyContentView()
    }
}