VonTobias Stephan

SwiftUI toggle action events

Der Toggle Switch in SwiftUI hat leider keinen “action” event, wie der Button. Wenn man in die geschweiften Klammern einen Funktionsaufruf einträgt, für das zu folgender Fehlermeldung:

Static method ‘buildBlock’ requires that ‘String’ conform to ‘View’

Der Trick ist, dass man hier ein View erzeugen muss.

Im Beispielcode findest Du die Zeile:

Text("Toggle \(ToggleAction(State: showResubmission))")

//
//  ContentView.swift
//  ToggleSwitchActionDemo
//
//  Created by T. Stephan on 22.02.20.
//  Copyright © 2020 eCommerce - Tobias Stephan. All rights reserved.
//

import SwiftUI
import Combine

class MainClass: ObservableObject {
   public var ToggleSwitchState = false

    init(){

    }
}

struct ContentView: View {
    @ObservedObject var oMainClass = MainClass()
       @State private var showResubmission = false
    var body: some View {
        Toggle(isOn: $showResubmission){
            Text("Toggle \(ToggleAction(State: showResubmission))")
            .padding()
        }
    }

    func ToggleAction(State: Bool) -> String {
        if (State != oMainClass.ToggleSwitchState)
        {
            oMainClass.ToggleSwitchState = State
            //do something else...
            print("Toggle switched...")
        }
        return String(State)
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}