ios - SwiftUI @FocusState - 如何赋予它初始值

Question

我很高兴看到 TextField 增强:focused(...): https://developer.apple.com/documentation/swiftui/view/focused(_:)
我想用它来展示一个非常简单的 SwitfUI View ，它只包含一个 TextField，它的焦点是立即打开键盘。无法使其工作:

    struct EditTextView: View {
        @FocusState private var isFocused: Bool
        @State private var name = "test"
// ...
        var body: some View {
            NavigationView {
                VStack {
                    HStack {
                        TextField("Enter your name", text: $name).focused($isFocused)
                            .onAppear {
                                isFocused = true
                            }
// ...

哪里不对了？我很难给它默认值。

Answer 1

我也无法在 Xcode 13，beta 5 上完成这项工作。为了解决这个问题，我推迟了对 isFocused = true 的调用。 . 那行得通!
我在这个错误背后的理论是在 onAppear 的时候TextField 还没有准备好成为第一响应者，所以 isFocused = true和 iOS 调用 becomeFirstResponder在幕后，但它失败了(例如， View 层次结构尚未完成设置)。

struct MyView: View {

  @State var text: String
  @FocusState private var isFocused: Bool

  var body: some View {
    Form {
      TextEditor(text: $text)
        .focused($isFocused)
        .onChange(of: isFocused) { isFocused in
          // this will get called after the delay
        }
        .onAppear {
          // key part: delay setting isFocused until after some-internal-iOS setup
          DispatchQueue.main.asyncAfter(deadline: .now()+0.5) {
            isFocused = true
          }
        }
    }
  }
}