如何在 SwiftUI 中禁用带有切换的文本字段？

Question

在swiftUI中使用Toogle时应该如何正确禁用TextField？如果我们禁用其中输入了一些值的 TextField，以下简单示例会在控制台中发出警告，删除它也不能解决问题。

struct ContentView: View {
@State var isToogleOn = false
@State var textFieldValue = ""

var body: some View {
    HStack {
        TextField("Placeholder", text: $textFieldValue)
            .disabled(!isToogleOn)
        Toggle("Activate textField", isOn: $isToogleOn)
        }
    }
}

关闭文本框时的警告：

=== AttributeGraph: cycle detected through attribute 160396 === 2022-01-08 15:27:46.182588+0100 CrochetIo[15460:1558507] [SwiftUI] Modifying state during view update, this will cause undefined behavior

Answer 1

其实是Apple的日志，所以我们不应该关心它们，但是如果它们打扰了你，那么可以解决，因为它们是由于TextField在禁用期间仍然处于焦点状态而发布的.

可能的方法是在带有注入的预设副作用的切换上使用代理绑定。

测试 Xcode 13.2 / iOS 15.2

struct ContentViewTestToggleText: View {
    @State var isToogleOn = false
    @State var textFieldValue = ""

    var body: some View {
        HStack {
            TextField("Placeholder", text: $textFieldValue)
                .disabled(!isToogleOn)

            let onToggle = Binding(
                get: { self.isToogleOn },
                set: {
                    if ![=10=] {
                        UIApplication.shared.endEditing()     // << here !!
                    }
                    
                    self.isToogleOn = [=10=]
                }
            )
            Toggle("Activate textField", isOn: onToggle)
        }
    }
}

extension UIApplication {
    func endEditing() {
        sendAction(#selector(UIResponder.resignFirstResponder), to: nil, from: nil, for: nil)
    }
}

Answer 2

@Asperi 给出的理由是正确的，但我会建议其他解决方案。当关闭 Toogle 时，让我们将焦点放在 TextField 上，然后才将其禁用。

    @State var isToogleOn = false
    @State var textFieldIsDisabled = false
    @State var textFieldValue = ""
    
    @FocusState private var focusField: Field?
    
    var body: some View {
        HStack {
            TextField("Placeholde", text: $textFieldValue)
                .focused($focusField, equals: .textField1)
                .disabled(textFieldIsDisabled)
            Toggle("Activate textField", isOn: $isToogleOn)
                .onChange(of: isToogleOn) { newValue in
                    focusField = nil
                    textFieldIsDisabled = !newValue
                }
        }
    }
}

如何在 SwiftUI 中禁用带有切换的文本字段？

How to disable TextField with Toogle in SwiftUI?

textfield

ios

swift

swiftui