如何在 SwiftUI 中使用 ForEach 参数？

Question

我们来看一个简单的代码：

 struct ContentView: View { let vocals = ["A", "E", "I", "O", "U"] var body: some View { HStack { ForEach(vocals, id: \.self) { letter in Button { } label: { Text(letter) } } } } func example() { // I would like to use letter here } }

如何在 ForEach 之外使用 letter 参数？

Answer 1

如果您想使用单个字母来修改vocals数组中的数据，您可以使用带index号的ForEach 。

struct ContentView: View {
@State var vocals = ["A", "E", "I", "O", "U"]
@State var catchLetter = "" //for store the clicked letter
var body: some View {
    VStack {
        HStack {
            ForEach(0..<vocals.count, id: \.self) { index in
                Button {
                    catchLetter = vocals[index]
                    example(modifyIndex: index)
                } label: {
                    Text(vocals[index])
                }
            }
        }
        Text("Caught letter: \(catchLetter)") //clicked letter
    }
}

func example(modifyIndex: Int) {
    vocals[modifyIndex] = "X" //change the clicked letter to "X"
}
}

Answer 2

更改您的函数，以便当您从按钮调用它时，它需要一个参数

func example(_ letter: String)

然后在 Button 中调用它

example(letter)

Answer 3

附加示例解决方案代码（复制类似问题）：

struct TestViewPage: View {
@State var animal: [String] = ["DOG", "CAT", "ELEPHANT", "ANT", "ZEBRA"]
@State var indexCatch = 0
var body: some View {
    TabView(selection: $indexCatch) {
        ForEach(animal.indices, id: \.self) { index in
            Text("swipe to move page\n\(animal[index])")
                .multilineTextAlignment(.center)
                .padding()
                .background(.blue)
                .cornerRadius(10)
        }
    }
    .tabViewStyle(PageTabViewStyle())
    .toolbar {
        ToolbarItem(placement: .navigationBarLeading) {
            Text("Current Page: \(animal[indexCatch])")
        }
        ToolbarItem(placement: .navigationBarTrailing) {
            Button("reset") {
                withAnimation {
                    indexCatch = 0 //go back to first page
                }
            }
        }
    }
}
}