ObservableObjectDemo.swift

import SwiftUI

class MyModel: ObservableObject {
  @Published var segmentedControlValue: Int = 0 {
    didSet {
      self.accumulator += 1
      print("segmentedControlValue set to \(self.segmentedControlValue)")
    }
  }
  @Published var accumulator: Int = 0
}

struct TestView: View {
  @ObservedObject var model = MyModel()
  var body: some View {
    VStack {
      Text("Pressed \(model.accumulator) times")
      Picker(selection: $model.segmentedControlValue, label: Text("Choose one")) {
        Text("0").tag(0)
        Text("1").tag(1)
      }.pickerStyle(SegmentedPickerStyle())
    }
  }
}

struct TestView_Previews: PreviewProvider {
  static var previews: some View {
    TestView()
  }
}