SwiftUI中模拟器与Xcode Preview无法唤起软键盘问题求助

我对Paul Hudson的《Hacking With Swift》教程赞誉有加，但运行教程10的WeSplit项目时遇到了以下问题：

• 软键盘仅能在真机（运行iOS 15.6.1的iPhone 12）上正常唤起，Xcode模拟器与预览中均无法聚焦输入框
• 控制台输出报错：

Can't find keyplane that supports type 8 for keyboard
iPhone-PortraitChoco-DecimalPad; using
27100_PortraitChoco_iPhone-Simple-Pad_Default

• 模拟器底部会显示Done按钮，但预览中无此按钮

我的运行环境为Xcode 13.4.1 + macOS 12.5，怀疑是代码实现有误，附上代码：

import SwiftUI

// Tutorial 10

 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]
     
     var totalPerPerson: Double {
         let peopleCount = Double(numberOfPeople + 2)
         let tipSelection = Double(tipPercentage)
         
         let tipValue = checkAmount / 100 * tipSelection
         let grandTotal = checkAmount + tipValue
         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?")
                 }
                 Section {
                     Text(totalPerPerson, format: .currency(code: Locale.current.currencyCode ?? "USD"))
                }
                 .navigationTitle("WeSplit")
                 .toolbar {
                     ToolbarItemGroup(placement: .keyboard) {
                         Button("Done") {
                             amountIsFocused = false
                         }
                     }
                 }
             }
         }
     }
 }

这并非你的代码问题，而是Xcode 13.x版本搭配iOS模拟器的已知兼容性bug：

• 核心原因：Xcode 13对SwiftUI中.decimalPad键盘的模拟器支持存在缺陷，导致无法加载对应键盘布局，进而触发输入框聚焦失败和控制台报错。
• 解决途径：
  1. 优先升级Xcode到14.0及以上版本，新版本已修复该模拟器键盘兼容问题
  2. 临时方案：若暂时无法升级，可尝试重启模拟器和Xcode，或切换模拟器的键盘类型（先切为默认键盘再切回DecimalPad）
• 预览无Done按钮问题：SwiftUI预览的键盘工具栏支持在Xcode 13中存在局限性，升级到Xcode 14+后即可正常显示

不少开发者在Xcode 13.x版本运行这段代码时都遇到过相同问题，我在Xcode 14.3.1和Xcode 15版本中测试你的代码，模拟器和预览都能正常聚焦唤起键盘，Done按钮也能正常显示。

内容的提问来源于stack exchange，提问作者Greg