How to edit an array in one struct from another struct in Swift?

Question

I have an array of "Workout Sets" in a struct called WorkoutBuilderView. My issue is that I need to access the contents of that array from a struct that is nested within the WorkoutBuilderView (as seen below). This struct does not need to be nested within the WorkoutBuilderView, but it is preferred. The only thing I really need is to be able to edit the sets array from another struct.

Possibly create an "inout" sort of parameter for a struct? (that only works in methods as far as I'm aware)

The array that needs to be accessed is called sets.
The location where it needs to be accessed is marked by a comment //access point

The code:

struct WorkoutBuilderView: View {


@State var sets = [WorkoutSet(id: 0, percentage: -1, repetitions: -1, alteredValue: .max)]

var body: some View {
    Background {
        Group {
            ...
            if self.sets.count > 0 {
                ScrollView {
                    ForEach(self.sets) { set in
                        WorkoutSetLayout(index: set.id) //where sets needs to be passed in
                    }
                }

            }
            ...
        }
    }
    }

//this is the struct where the array needs to be accessed
struct BuilderPicker: View {

    let name: String
    let options: Array<String>
    let setIndex: Int


    @State var selectedOption = 0
    var body: some View {
        HStack {
            ...
        }

        .onReceive([self.selectedOption].publisher.first()) { (value) in

            //change sets here
            //access point
            print(value)

        }
    }

}

//layout (sets needs to pass through here too)
struct WorkoutSetLayout: View {
    let index: Int
    var body: some View {
        VStack(alignment: .leading) {
            Text("Set \(index + 1)")
            ...
            //the array needs to go into the BuilderPicker where it will be edited
            BuilderPicker(name: "Weight % of", options: [AlteredValue.max.rawValue, AlteredValue.weight.rawValue], setIndex: index)
            ...
        }
    }
}
//you probably don't need to worry about the Background
struct Background<Content: View>: View {
    private var content: Content

    init(@ViewBuilder content: @escaping () -> Content) {
        self.content = content()
    }

    var body: some View {
        EmptyView()
            .frame(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
            .overlay(content)
            .padding(.top, 75)
    }
}


}

score 1 · Accepted Answer · answered Nov 04 '19 at 06:00

If I correctly understand your question, the @Binding is exactly for this purpose

1) Add binding var to nested struct, as

//layout (sets needs to pass through here too)
struct WorkoutSetLayout: View {
    let index: Int
    @Binding var data: [WorkoutSet]
    ...

2) Bind model in parent with nested via initialiser, as

ForEach(self.sets) { set in
    WorkoutSetLayout(index: set.id, data: self.$sets)
}

How to edit an array in one struct from another struct in Swift?

1 Answers1