change binding of List with button press

Question

Created Feb ’21

Replies 2

Boosts 0

Participants 2

Hi, I'm new to swiftUI and am having a few issues getting my head around how it works.

My immediate issue is that I'm getting a response from an api in the form of a JSON string that I'm splitting into 2 arrays of my data model.

This works fine and I have 2 lists in my view that if I change the binding in my list, the data changes to the other list.

I can't seem to get it to change on a button click though. I want 2 buttons (one for each list) and clicking them will change the binding.
I've got to the stage where I feel I'm soooooo close, but am missing something obvious.

This is the code in my view:

Code Block struct SplitView: View {
    @EnvironmentObject var viewRouter: ViewRouter
    @State var list1 = [MyModel]()
    @State var list2 = [MyModel]()
    private var viewingModels: [MyModel] {
        list1
    }
    var body: some View {
        HStack {
            Button(action: {
                //selected = 1
            }){
                Text("List 1")
            }
            Button(action: {
                //selected = 2
            }){
                Text("List 2")
            }
        }
        List(viewingModels, id: \.ID) { myitem in
                HStack(alignment: .center) {
                    VStack(alignment: .leading) {
                        Text(myitem.Name)
                            .font(.subheadline)
                            .fontWeight(.bold)
                            Spacer()
                    }
                }
        } //end list
        .onAppear(perform: loadList)
        Spacer()
    }
}

So, I have my @State variables list1 and list2 and if I change which one appears in viewingModels, the list changes.

How can I do this on the button presses?

Thanks

Answered by OOPer in 660614022

I may be missing something, but why don't you simply add an @State variable to choose the lists?

Code Block struct SplitView: View {
    @EnvironmentObject var viewRouter: ViewRouter
    @State var list1 = [MyModel]()
    @State var list2 = [MyModel]()
    
    @State var selected: Int = 1
    private var viewingModels: [MyModel] {
        switch selected {
        case 1:
            return list1
        case 2:
            return list2
        default:
            return []
        }
    }
    var body: some View {
        HStack {
            Button(action: {
                selected = 1
            }){
                Text("List 1")
            }
            Button(action: {
                selected = 2
            }){
                Text("List 2")
            }
        }
        List(viewingModels, id: \.ID) { myitem in
                HStack(alignment: .center) {
                    VStack(alignment: .leading) {
                        Text(myitem.Name)
                            .font(.subheadline)
                            .fontWeight(.bold)
                            Spacer()
                    }
                }
        }
        .onAppear(perform: loadList)
        Spacer()
    }
    
}

Boost

Answer 1

OOPer OP

Feb ’21

Accepted Answer

I may be missing something, but why don't you simply add an @State variable to choose the lists?

Code Block struct SplitView: View {
    @EnvironmentObject var viewRouter: ViewRouter
    @State var list1 = [MyModel]()
    @State var list2 = [MyModel]()
    
    @State var selected: Int = 1
    private var viewingModels: [MyModel] {
        switch selected {
        case 1:
            return list1
        case 2:
            return list2
        default:
            return []
        }
    }
    var body: some View {
        HStack {
            Button(action: {
                selected = 1
            }){
                Text("List 1")
            }
            Button(action: {
                selected = 2
            }){
                Text("List 2")
            }
        }
        List(viewingModels, id: \.ID) { myitem in
                HStack(alignment: .center) {
                    VStack(alignment: .leading) {
                        Text(myitem.Name)
                            .font(.subheadline)
                            .fontWeight(.bold)
                            Spacer()
                    }
                }
        }
        .onAppear(perform: loadList)
        Spacer()
    }
    
}

0

Answer 2

Gimbal5401 OP

Feb ’21

You are a star. Thank you so much.
I had a feeling it was something silly I was missing. I was just going round and round in circles.

Thanks again.

0