嗨，对不起，如果这是一个愚蠢的问题。
我一直在关注HackingWithSwift SwiftUI教程第19天（link）但我面临着一个问题。我试图使用.focus()修饰符和布尔值来处理一个按钮，并在用户按下完成时隐藏我的键盘。每当我试图隐藏我的键盘时，我有2个"完成"按钮，即使我刚刚添加了一个到我的UI，即使我删除了一个按钮，它也不会显示"完成"按钮，我无法隐藏我的键盘。
注意：我在Preview和iPhone模拟器上试用过，但没有在物理设备上试用。
我添加了一个截图和代码以及。
下面是我的代码：

//  ContentView.swift
//  WeSplit

import SwiftUI

struct ContentView: View {
    @State private var checkAmount = 0.0
    @State private var numberOfPeople = 2
    @State private var tipPercentage = 20
    @FocusState private var amountIsFocused: Bool
    
    let tipPercentages = [10, 15, 20, 25, 0]
    
    //For Total cost + tip
    var grandTotal: Double{
        let tipSelection = Double(tipPercentage)
        let tipValue = checkAmount / 100 * tipSelection
        let grandTotal = checkAmount + tipValue
        
        return grandTotal
    }
    
    
    //For individual share
    var totalPerPerson: Double{
        let peopleCount = Double(numberOfPeople + 2)
        let amountPerPerson = grandTotal / peopleCount
    
        return amountPerPerson
    }
    
    
    
    var body: some View {
        NavigationView {
            Form{
                Section{
                    TextField("Amount: ", value: $checkAmount, format: .currency(code: Locale.current.currencyCode ?? "USD"))
                        .keyboardType(.decimalPad)
                        .focused($amountIsFocused)
                    
                    Picker("Number of people", selection: $numberOfPeople){
                        ForEach(2..<100){
                            Text("\($0) people")
                        }
                    }
                }
                
                Section{
                    Picker("Tip Percentage", selection: $tipPercentage){
                        ForEach(tipPercentages, id:\.self){
                            Text($0, format: .percent)
                        }
                    }.pickerStyle(.segmented)
                                        
                }header: {
                    Text("How much tip do you want to leave?")
                }
                
                
                //Grand Total
                Section{
                    Text(grandTotal, format:.currency(code: Locale.current.currencyCode ?? "USD"))
                }header: {
                    Text("Total Cost + Tip")
                }
                
                
                //Showing each person's share
                Section{
                    Text(totalPerPerson, format: .currency(code: Locale.current.currencyCode ?? "USD"))
                }header: {
                    Text("Amount Per Person")
                }.navigationTitle("WeSplit")
                    .toolbar(){
                        ToolbarItemGroup(placement: .keyboard){
                            
                            Button("Done"){
                                amountIsFocused = false
                            }
                        }
                    }
                
                
                
            
            }
        }
    }
        
}


struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

下面是截图：