How do you get a bound variable to clear?

Question

If $score is bound to score, how come the textfield won't clear? How do I make it clear? Also, how would I get "Enter Score" to show rather than "0"? Thanks.

import SwiftUI

struct keyType: View {
    
    @State private var score: Double = 0
    
    let formatter: NumberFormatter = {
        let formatter = NumberFormatter()
        formatter.numberStyle = .decimal
        formatter.maximumFractionDigits = 2
        return formatter
    }()
    
    func buttonClear() {
        self.score = 0;
    }
    
    var body: some View {
        VStack {
            TextField("Enter Score", value: $score, formatter: formatter)
                .textFieldStyle(RoundedBorderTextFieldStyle())
                .padding()
            Text(String(format: "Your Score: %.2f", score))
            
            Button("CLEAR") {buttonClear()}
                .padding()
        }
    }
}

Answer 1

If you use TextField(value: format:) the "empty" value is 0, but the prompt "Enter score" is only shown when the input string is "".

But you can use the standard TextField(text:) version and convert to a value manually. Then the prompt shows.

struct ContentView: View {
    
    @State private var score: Double = 0
    
    @State private var scoreTextInput = ""
    
    func buttonClear() {
        self.score = 0
        self.scoreTextInput = ""
    }
    
    var body: some View {
        VStack {
            TextField("Enter Score", text: $scoreTextInput, onCommit: {
                score = Double(scoreTextInput) ?? 0
            })
            .textFieldStyle(RoundedBorderTextFieldStyle())
            .padding()
            Text("Your Score: \(score, specifier: "%.2f")")
            
            Button("CLEAR") {buttonClear()}
                .padding()
        }
    }
}