当用户点击 SwiftUI 中的列表行时如何显示警报

Question

当用户在 SwiftUI 中点击列表中的行时，显示包含该行数据的警报的最佳方式是什么？

我正在使用此代码。

import SwiftUI

struct ContentView: View {

    var testData = ["One","Two","Three"]

    var body: some View {

        List{
            ForEach(testData, id: \.self) { item in
                Text(item).onTapGesture {

                    if item == "One" {

                        print("One selected")

                        print("NEED TO SHOW THE ALERT HERE")

                    }

                }
            }

        }

    }

}

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

我试图通过这种方式解决问题：

import SwiftUI

struct ContentView: View {

    @State private var showingAlert = false

    var testData = ["One","Two","Three"]

    var body: some View {

        List{
            ForEach(testData, id: \.self) { item in

                Button(action: {
                    self.showingAlert = true

                }) {
                    Text("\(item)")

                }
                .alert(isPresented: self.$showingAlert) {
                    Alert(title: Text("Text"), message: Text(item), dismissButton: .default(Text("Ok")))

                }

            }

        }

    }

}

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

但是这个解决方案会导致这个警告：

Attempt to present <UIAlertController:>  which is already presenting <UIAlertController:>

寻找更好的解决方案或避免此警告的解决方案。

Answer 1

这是由于更新时为所有单元格呈现单个变量，因此您可以尝试

struct ContentView: View {

    @State private var showingAlert = false

    @State private var item = "" // track last clicked item

    var testData = ["One","Two","Three"]

    var body: some View {

        List{
            ForEach(testData, id: \.self) { item in

                Button(action: {
                    self.item = item
                    self.showingAlert = true

                }) {
                    Text("\(item)")

                }

            }

        }.alert(isPresented: self.$showingAlert) {
                Alert(title: Text("Text"), message:Text(item), dismissButton: .default(Text("Ok")))
        }

    }

}

Answer 2

您的代码为每个项目创建一个单独的警报。 将alert调用ForEach之外，那么只会创建一个警报实例。