ForEach 和 SwiftUI 的索引不断提供"Closure containing control flow statement cannot be used with result build

Question

我正在尝试创建一个ForEach循环，用于查找当前所选选择器值的索引。但我不断收到这些错误消息：CCD_ 1，CCD_ 2，Closure containing control flow statement cannot be used with result builder 'TableRowBuilder'

@State private var loc: Double = 0
@State private var selectedLine = "N Q R W"
Picker("Lines", selection: $selectedLine) {
ForEach(station.groups, id: .self) {
Text($0)
}
}
.padding(.all, 6.0)
.pickerStyle(.segmented)
ForEach (0 ..< station.groups.count, id: .self) { i in //first 2 errors here
Text("Value: (station.groups[i])")
if station.groups[i] == selectedLine { //second error
loc = station.groups.index(of: selectedLine)
}
}

station.group是JSON文件中的非静态变量。例如["N Q R W","one two three"]或["A C E","B D F M"]非常感谢。

编辑：我找到了一个变通办法。

Picker("Lines", selection: $selectedLine) {
ForEach(0..<station.groups.count, id: .self) { i in
Text(station.groups[i])
}
}
.padding(.all, 6.0)
.pickerStyle(.segmented)

selectedLine是Int，现在它输出0，1，2，&3而不是数组值。

Answer 1

ForEach是一个Referencing initializer 'init(_:id:content:)' on 'ForEach' requires that 'Text' conform to 'TableRowContent'0，它不是for循环，不能使用.self或array.count，必须提供一个作为数据唯一标识符的键，或者让数据结构实现Identifiable，并从JSON数据中设置let id。