How do I change the bool value of an item that comes from a struct and hence update a checklist?

Question

Background
I am trying to build a list with a checkmark/tick box next to it. A struct is used to create the "data" for each item. This is then passed on to a class which holds an array of the items created by the struct. From here I used the observable object protocol and passed the class into a list.

Objective
I would like to be able to individually mark each item as completed when it is done.

Current Analysis
I know the image switches when I manually change the 'completed' value from false to true. I also tested the onTapAction just to be sure it is working. I think the problem lies in "self.one.completed.toggle()" or the binding or something I am unaware of.

struct One: Identifiable, Codable {
     let id = UUID()
     var item: String
    var completed:Bool = false
}

class OneList: ObservableObject{
    @Published var items1 = [One]()





struct ContentView: View {

    @ObservedObject var itemss1 = OneList()
    @ObservedObject var itemss2 = TwoList()
    @ObservedObject var itemss3 = ThreeList()
    @ObservedObject var itemss4 = FourList()

    @State private var  showingAdditem: Bool = false

    @Binding var one:One

    var body: some View {

        NavigationView{
            ZStack{
                List{
                    Section(header: Text("Vital")){
                        ForEach(itemss1.items1){ item in
                                    HStack{

                                        Image(systemName: self.one.completed ? "checkmark.circle":"circle")
                                            .onTapGesture {
                                                self.one.completed.toggle()

                                        }

                                        Text(item.item)}

P.S. I am relatively new to Swift and Stack overflow so any other suggestions would be appreciated

Can you update your code listing so that it can actually be compiled and run? You have `@Binding var one: One`, and it probably matters where that is coming from, for starters. Your listing should be the most minimal example that demonstrates your problem. — arsenius, Dec 18 '19 at 01:22

score 0 · Accepted Answer · answered Dec 18 '19 at 03:35

In my other answer I achieved something like this with ObservableObject protocol for needed object and then playing with EnvironmentObject. Actually I didn't try to do this with other wrappers. Here is the code, where you can see switching images:

import SwiftUI

class One: Identifiable, ObservableObject { // ObservableObject requires class

    let id: UUID
    var item: String = "[undefined]"
    @Published var completed: Bool = false // this will affect the UI

    init(item: String, completed: Bool) {
        id = UUID()
        self.item = item
        self.completed = completed
    }

}

class OneList: ObservableObject{
    @Published var items = [One(item: "first", completed: false),
                            One(item: "second", completed: false),
                            One(item: "third", completed: false)]
}

struct CheckboxList: View {

    @EnvironmentObject var itemList: OneList

    var body: some View {
        List {
            Section(header: Text("Vital")) {
                ForEach(itemList.items.indices) { index in
                    VitalRow()
                        .environmentObject(self.itemList.items[index])
                        .onTapGesture {
                            self.itemList.items[index].completed.toggle()
                        }
                }
            }
        }
    }
}

struct VitalRow: View {
    @EnvironmentObject var item: One
    var body: some View {
        HStack{
            Image(systemName: item.completed ? "checkmark.circle" : "circle")
            Text("\(item.item)")
        }
    }
}

struct CheckboxList_Previews: PreviewProvider {
    static var previews: some View {
        CheckboxList().environmentObject(OneList())
    }
}

Just following up with this, I have a "plus button" that lets me add items to the list. Using the suggested method I am now unable to add these items to the list. Any suggestions or do you need to see the button code? — Murray Gordon, Dec 18 '19 at 20:15
@MurrayGordon, sorry for late answer, I'm unable for few days to work. But I'm surprised, why it is so? It must be easy, something like ```Button(action: { self.itemList.items.append(One(item: "third", completed: false)) } ) ...```. Or better to make ```func addItem(_ newItem) { items.append...}``` in ```OneList``` class and it should affect the UI. Text me, does this code work or not, but I'll answer only in few days =( — Hrabovskyi Oleksandr, Dec 20 '19 at 05:48
The button seems to be working well but I get this from the terminal- AddGestureModifier<_EndedGesture>>> count (2) != its initial count (1). `ForEach(_:content:)` should only be used for *constant* data. Instead conform data to `Identifiable` or use `ForEach(_:id:content:)` and provide an explicit `id`! — Murray Gordon, Dec 20 '19 at 07:24
Might be something to do with the ForEach(itemList.items.indicies)? — Murray Gordon, Dec 20 '19 at 07:25

How do I change the bool value of an item that comes from a struct and hence update a checklist?

1 Answers1