swift - 如何将值从EnvironmentObject传递到SwiftUI中的类实例？

我正在尝试从名为userSettings的EnvironmentObject的值分配给名为categoryData的类实例，在这里尝试将值分配给类ObserverCategory(userID: self.userSettings.id)时出现错误

错误提示:Cannot use instance member 'userSettings' within property initializer; property initializers run before 'self' is available
这是我的代码:

这是我的环境对象类:

//user settings
final class UserSettings: ObservableObject {
    @Published var name : String = String()
    @Published var id : String = "12345"
}

接下来是我尝试分配其值的代码:

//user settings
@EnvironmentObject var userSettings: UserSettings

//instance of observer object
@ObservedObject var categoryData = ObserverCategory(userID: userSettings.id)

class ObserverCategory : ObservableObject {

    let userID : String

    init(userID: String) {

        let db = Firestore.firestore().collection("users/\(userID)/categories") //

        db.addSnapshotListener { (snap, err) in
            if err != nil {
                print((err?.localizedDescription)!)
                return
            }

            for doc in snap!.documentChanges {

                //code

            }
        }
    }
}

有人可以指导我解决此错误吗？

谢谢

最佳答案

因为@EnvironmentObject和@ObservedObject正在同时初始化。因此，您不能将其中一个用作另一个参数。

您可以使ObservedObject更加懒惰。因此，您可以在EnvironmentObject可用时将其关联。例如:

struct CategoryView: View {

    //instance of observer object
    @ObservedObject var categoryData: ObserverCategory

    var body: some View { ,,, }
}

然后像这样传递它:

struct ContentView: View {

    //user settings
    @EnvironmentObject var userSettings: UserSettings

    var body: some View {
        CategoryView(categoryData: ObserverCategory(userID: userSettings.id))
    }
}