SwiftUI TextField with formatter not working?

Question

I\'m trying to get a numeric field updated so I\'m using a TextField with the formatter: parameter set. It formats the number into the entry field just fine, but does not up

Answer 1

Inspired by above accepted proxy answer, here is a ready to use struct with fair amount of code. I really hope Apple can add an option to toggle the behavior.

struct TextFieldRow: View {
    var value: Binding
    var title: String
    var subtitle: String?

    var valueProxy: Binding {
        switch T.self {
        case is String.Type:
            return Binding(
                get: { self.value.wrappedValue as! String },
                set: { self.value.wrappedValue = $0 as! T } )
        case is String?.Type:
            return Binding(
                get: { (self.value.wrappedValue as? String).bound },
                set: { self.value.wrappedValue = $0 as! T })
        case is Double.Type:
            return Binding( get: { String(self.value.wrappedValue as! Double) },
                set: {
                    let doubleFormatter = NumberFormatter()
                    doubleFormatter.numberStyle = .decimal
                    doubleFormatter.maximumFractionDigits = 3

                    if let doubleValue = doubleFormatter.number(from: $0)?.doubleValue {
                        self.value.wrappedValue = doubleValue as! T
                    }
                }
            )
        default:
            fatalError("not supported")
        }
    }
    
    var body: some View {
        return HStack {
            VStack(alignment: .leading) {
                Text(title)
                if let subtitle = subtitle, subtitle.isEmpty == false {
                    Text(subtitle)
                        .font(.caption)
                        .foregroundColor(Color(UIColor.secondaryLabel))
                }
            }
            Spacer()
            TextField(title, text: valueProxy)
            .multilineTextAlignment(.trailing)
        }
    }
}