Firestore 数据不会显示在列表视图中。可识别设置不正确？

Question

我正在尝试从 firebase 文档中获取一些数据并将其显示在 ListView 中。获取数据并将其解码到我自己的结构中效果很好（通过让控制台打印它进行测试），但它不会显示在实际的 ListView 中。我尝试创建 2 个示例数据集来查看我的 struct 和/或 ListView 的实现是否有任何问题，但它们显示得很好。 我最好的猜测是 ListView 对我从 firebase 文档中获得的 id 不满意。

这是我获取数据的方法（请暂时忽略 checkAvailablePkgs() 中丑陋的解决方案，这将会改变）：

class firebaseController : ObservableObject {
    let databaseFIRB = Firestore.firestore()
    @Published var forUserAvailablePkgs : [DLPackage] = []
   
func checkAvailablePkgs() {
        if Auth.auth().currentUser != nil {
            var allAccessiblePkgs : [String] = []
            let userUID = Auth.auth().currentUser!.uid
            databaseFIRB.collection("user-access").document(userUID).getDocument { (document, error) in
                if let document = document, document.exists {
                    let dataDescription = document.data().map(String.init(describing:)) ?? "nil"
                    let pkgArr = dataDescription.components(separatedBy: ", ")
                    for partString in pkgArr {
                        var tmpStringSlicing : String
                        tmpStringSlicing = partString.replacingOccurrences(of: "\": <null>", with: "")
                        tmpStringSlicing = tmpStringSlicing.replacingOccurrences(of: "[\\[\\]\"]", with: "", options: .regularExpression)
                        allAccessiblePkgs.append(tmpStringSlicing)
                    }
                    self.checkIndividualPkgInformation(pkgIDs: allAccessiblePkgs)
                } else {
                    print("Document does not exist")
                }
            }
        }
    }

    func checkIndividualPkgInformation(pkgIDs: [String]) {
        for id in pkgIDs {
            databaseFIRB.collection("download-pkgs").document(id).getDocument { (document, error) in
                if let document = document, document.exists {
                    let result = Result {
                        try document.data(as: DLPackage.self)
                    }
                    switch result {
                        case .success(let pkg):
                            if let pkg = pkg {
                                // A `Package` value was successfully initialized from the DocumentSnapshot.
                                print("Package: \(pkg)")
                                self.forUserAvailablePkgs.append(pkg)
                            } else {
                                // A nil value was successfully initialized from the DocumentSnapshot,
                                // or the DocumentSnapshot was nil.
                                print("Document does not exist")
                            }
                        case .failure(let error):
                            // A `City` value could not be initialized from the DocumentSnapshot.
                            print("Error decoding package: \(error)")
                        }
                } else {
                    print("Package-Document does not exist")
                }
            }
        }
    }
}

这是我想要将其保存为的结构：

struct DLPackage: Identifiable, Codable {
    @DocumentID var id = UUID().uuidString
    var name : String = ""
    var size : String = ""
    var contentpaths : [String] = [""]
}

这是拒绝显示获取的数据的 ListView ：

struct FIRBauthView: View {
    let firebaseCtrl: firebaseController = firebaseController()
    var body: some View {
        VStack() {
            List(firebaseCtrl.forUserAvailablePkgs) {item in
                HStack() {
                    Text(String(item.name)).font(.custom("Avenir", size: 26))
                    Spacer()
                    Text(String(item.size)).font(.custom("Avenir", size: 26))
                }
            }
            Button {
                firebaseCtrl.checkAvailablePkgs()
            } label: {
                Text("Check")
            }
        }
    }
}

我可以给我的 firebaseControler().forUserAvailablePkgs 一个初始值：

forUserAvailablePkgs.append(contentsOf: [DLPackage(name: "Example", size: "1GB", contentpaths: ["hello","something"]),DLPackage(name: "Nr2", size: "1GB", contentpaths: ["hello","something else"])])

并且它们会很好地显示。

这是我从加载到 forUserAvailablePkgs 数组中的 firebase 数据中打印出来的：

[Light_Player.DLPackage(_id: FirebaseFirestoreSwift.DocumentID<Swift.String>(value: Optional("CDB68E0C-DCE2-4FAA-AD55-872322A55E56")), name: "Example", size: "1GB", contentpaths: ["hello", "something"]), 
Light_Player.DLPackage(_id: FirebaseFirestoreSwift.DocumentID<Swift.String>(value: Optional("DCAAF136-24FE-470A-B897-2D178AEDB3A0")), name: "Nr2", size: "1GB", contentpaths: ["hello", "something else"]), 
Light_Player.DLPackage(_id: FirebaseFirestoreSwift.DocumentID<Swift.String>(value: Optional("package2")), name: "Bewährte Klassiker", size: "3.4GB", contentpaths: ["placeholder for another path", "placeholder for a different path"]), 
Light_Player.DLPackage(_id: FirebaseFirestoreSwift.DocumentID<Swift.String>(value: Optional("package1")), name: "Basic", size: "7.3GB", contentpaths: ["placeholder for path", "placeholder for path 2"])]

我尝试将结构的 id 更改为：

@DocumentID var id: String?

因为我在在线教程中找到了它，但是代码不会以这种方式进行复制。

我还尝试在从数据库获取数据后使用生成的 UUID 覆盖 firebase 数据中的 id，但我仍然无法让 ListView 显示它。

任何帮助表示赞赏。

Answer 1

经过一晚的良好睡眠后，我的暂时失明得到了治愈，并发现我在视图中缺少 @ObservedObject 属性。

struct FIRBauthView: View {
    @ObservedObject var firebaseCtrl: firebaseController = firebaseController()

而不是

struct FIRBauthView: View {
    let firebaseCtrl: firebaseController = firebaseController()

现在数据按预期显示。