I'm trying to add a custom button to the decimalPad so that I can input negative integers for various fields, but I'm stuck. I have no idea what to put in the Button code. I've seen other apps do this and I tried searching on the Internet but couldn't really find anything relavent. I know a workaround is to use the numbersAndPunctuation keyboard but I'd prefer the decimalPad. Can someone please help?

struct ContentView: View {
    @State private var amount1 = 0
    @State private var amount2 = 0
    @State private var amount3 = 0
    @FocusState var amountIsFocused: Bool

    var body: some View {
        NavigationView{
            Form {
                TextField("Amount 1", value: $amount1, format: .number)
                    .focused($amountIsFocused)
                    .keyboardType(.decimalPad)
                TextField("Amount 2", value: $amount2, format: .number)
                    .focused($amountIsFocused)
                    .keyboardType(.decimalPad)
                TextField("Amount 3", value: $amount3, format: .number)
                    .focused($amountIsFocused)
                    .keyboardType(.decimalPad)
            }
            .toolbar {
                ToolbarItemGroup(placement: .keyboard) {
                    Spacer()
                    Button("-") {

                    }
                    Button("Done") {
                        amountIsFocused = false
                    }
                }
            }
        }
    }
}

I played around with this some more and still haven't figured out how to implement it on the keyboard. This is a step in the direction, I'm trying to go, though it seems like duct tape coding. There's got to be a better way to do this.

enum WhichAmount {
    case one, two, three
}

class Amounts: ObservableObject {
    @Published var amount1 = 0
    @Published var amount2 = 0
    @Published var amount3 = 0
}

struct MinusView: View {
    @ObservedObject var amounts: Amounts
    let whichAmount: WhichAmount
    @FocusState var amountIsFocused: Bool

    var body: some View {
        HStack {
            TextField("Enter value:", value: whichAmount == .one ? $amounts.amount1 : whichAmount == .two ? $amounts.amount2 : $amounts.amount3, format: .number)
                .keyboardType(.decimalPad)
                .focused($amountIsFocused)
            Button("-") {
                switch whichAmount {
                case .one:
                    amountIsFocused = false
                    amounts.amount1 *= -1
                case .two:
                    amountIsFocused = false
                    amounts.amount2 *= -1
                case .three:
                    amountIsFocused = false
                    amounts.amount3 *= -1
                }
            }
        }
    }
}

struct ContentView: View {
    @StateObject var amounts = Amounts()
    @FocusState var amountIsFocused: Bool

    var body: some View {
        NavigationView{
            Form {
                MinusView(amounts: amounts, whichAmount: .one)
                MinusView(amounts: amounts, whichAmount: .two)
                MinusView(amounts: amounts, whichAmount: .three)
            }
        }
    }
}