I'm very new to Swift and SwiftUI so apologies for the very basic question. I must be misunderstanding something about the SwiftUI lifecycle and it's interaction with @State.

I've have a list, and when you click on the row, it increments a counter. If I click on some row items to increment the counter, scroll down, and scroll back up again - the state is reset to 0 again. Can anyone point out where I'm going wrong? Many thanks.

struct TestView : View {
    @State private var listItems:[String] = (0..<50).map { String($0) }
    var body: some View {
        List(listItems, id: \.self) { listItem in
            TestViewRow(item: listItem)
        }
    }
}

struct TestViewRow: View {
    var item: String
    @State private var count = 0

    var body: some View {
        HStack {
            Button(item, action: {
                self.count += 1
            })
            Text(String(self.count))
            Spacer()
        }
    }
}