Error binding textfield to object in array - macos

Question

I have an array of SplitItem objects I am trying to do a for loop on them and show a textfield. I keep getting the error Use of unresolved identifier '$item' for this code,
import SwiftUI
struct ContentView: View {
#State var selectedAccount:Int = -1
#State var splitItems:[SplitItem] = [
SplitItem(account: 0, amount: "1.00", ledger: .Accounts),
SplitItem(account: 0, amount: "2.00", ledger: .Accounts),
SplitItem(account: 0, amount: "3.00", ledger: .Budgets),
SplitItem(account: 0, amount: "4.00", ledger: .Budgets)
]
var body: some View {
VStack {
ForEach(self.splitItems) { item in
TextField(item.amount, text: $item.amount)
}
}.frame(maxWidth: .infinity, maxHeight: .infinity)
}
}
struct SplitItem: Identifiable {
#State var id:UUID = UUID()
#State var account:Int
#State var amount:String
#State var ledger:LedgerType
}
enum LedgerType:Int {case Accounts=0,Budgets=1}
if I change the text: $item.amount to text: item.$amount it compiles but the resulting textfield does not let me change it. The same thing if I change the for loop to indices and try to bind based on the index,
ForEach(self.splitItems.indices) { index in
TextField(self.splitItems[index].amount, text: self.$splitItems[index].amount)
}
it has no problem showing a Text(item.amount) its only when I try to bind do I have a problem. I think it has something to do with it being an array because if I try to bind a single splititem not in an array to a textfield it works just fine.
edit I also tried making a subview with the textfield and calling that from the foreach loop but I got the same error.
also this is swiftui for Mac not iOS.

Answer 1

It is not Mac nor iOS specific.
First of all, use the state as the single source of truth for a given view only.
In your case, move your data and business logic to your model, represented by some ObservableObject. In your View use #ObservedObject property wrapper.
Your (simplified) data structure and model could be defined as
struct Item: Identifiable {
let id = UUID()
var txt = ""
}
class Model: ObservableObject {
#Published var items = [Item(txt: "alfa"), Item(txt: "beta")]
}
Now you are ready tu use this model in View. When the state value changes, the view invalidates its appearance and recomputes the body, and the same is true for ObservedObject.
struct ContentView: View {
#ObservedObject var model = Model()
var body: some View {
VStack {
ForEach(model.items.indices) { idx in
VStack {
Text(self.model.items[idx].txt.capitalized).bold()
TextField("label", text: self.$model.items[idx].txt).frame(idealWidth: 200)
}
}
}.frame(maxWidth: .infinity, maxHeight: .infinity)
}
}