SwiftUI：手势不起作用，它不会移动

Question

我有一个User数组，我的目标是构建类似Tinder的东西。这样用户可以向右或向左滑动，但是我在手势上失败了，该卡不会移动。

import SwiftUI

struct ContentView: View {
    var users: [User] = [
        User(id: "1", imageName: "Card2", position: CGSize.zero),
        User(id: "2", imageName: "Card3", position: CGSize.zero),
        User(id: "3", imageName: "Card4", position: CGSize.zero)
    ]

    var body: some View {
            ZStack {
                ForEach(users, id: \.imageName) { user in
                    CardView(imageName: user.imageName, position: user.position)
                        .offset(x: user.position.width, y: user.position.height)
                        .animation(.spring(response: 0.3, dampingFraction: 0.6, blendDuration: 0))
                        .gesture(
                            DragGesture()
                                .onChanged { value in
                                    user.position = value.translation

                                }
                                .onEnded { value in
                                    user.position = .zero
                                }
                    )
                }

            }
    }
}

这是用户结构

struct User: Identifiable {
    var id: String
    var imageName: String
    @State var position: CGSize
}

卡，当我尝试移动它时不会移动。