在 SwiftUI 的 Picker 中添加新元素 [英] Add new Element in Picker in SwiftUI

问题描述

我找不到如何在 SwiftUI 的选择器视图中添加某些元素，在我的示例中，我想在单击按钮时在选择器中添加Z"值.

I can't find how to add some element in a picker view in SwiftUI, in my sample, I want add "Z" value in picker when I click the button.

struct ContentView: View {
@State var values: [String] = ["A", "B", "C"]

@State private var selectedValue = 0

var body: some View {
    NavigationView {
        Form {
            Section {
                Picker(selection: $selectedValue, label: Text("Value")) {
                    ForEach(0 ..< values.count) {
                        Text(self.values[$0])

                    }
                }
            }
            Button(action: {
        self.values.append("Z")
            }, label: {
                Text("Add")
            })
        }.navigationBarTitle("Select a value")

    }
}

当我点击按钮时，Z 被添加到values"数组中，但 Picker 没有刷新.

When I click on the button, Z is added to "values" array but Picker is not refreshed.

谢谢:)

推荐答案

您必须通过 id 来识别 SwiftUI 的值，以使其更改可检测:

You must identify values by id for SwiftUI to make it's changes detectable:

ForEach(0 ..< self.values.count, id: \.self) {
    Text(self.values[$0])
}

这样 SwiftIU 就知道它应该在更改时重建选择器.

This way SwiftIU knowns it should rebuild the picker on change.

提示:您可以像这样直接使用元素:

Tip: You can use elements directly like this:

ForEach(values, id: \.self) {
    Text($0)
}

不要忘记更改 selectedValue 类型和值以匹配您遵循上述提示的数据源 IF:

Don't forget to change the selectedValue type and value to match with the dataSource IF you followed the tip above:

@State private var selectedValue = "A"

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