ByTobias Stephan

SwiftUI toggle action events

The toggle switch in SwiftUI unfortunately has no “action” event like the button. If you enter a function call in the curly brackets, you will get the following error message:

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

The trick is to create a view here.

In the example code you will find the line:

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

That’s solution. Take the ToggleAction function and expand it for your purposes. In this example, the status variable is simply entered as return value.

//
//  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()
    }
}