當用戶點擊 SwiftUI 中的列表行時如何顯示警報

Question

當用戶在 SwiftUI 中點擊列表中的行時，顯示包含該行數據的警報的最佳方式是什么？

我正在使用此代碼。

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()
    }
}

我試圖通過這種方式解決問題：

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()
    }
}

但是這個解決方案會導致這個警告：

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

尋找更好的解決方案或避免此警告的解決方案。

Answer 1

這是由於更新時為所有單元格呈現單個變量，因此您可以嘗試

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

您的代碼為每個項目創建一個單獨的警報。 將alert調用ForEach之外，那么只會創建一個警報實例。