打印 Firebase 文档

Question

我只想打印一个 firebase 文档而不是整个集合，我不知道该怎么做。 目前我的代码看起来像这样，但它打印整个“用户”集合，我希望能够只打印专用于所选用户的文档：

struct Users: Identifiable {
    var id: String = UUID().uuidString
    var code_postal: String
    var creatdAt: String
    var email: String
    var is_new: String
    var nom: String
    var prenom: String
    var tel: String
    var ville: String
}

class UsersViewModel: ObservableObject {
    @Published var users = [Users]()
    private var db = Firestore.firestore()
    let is_user = Auth.auth().currentUser

    func fetchDate() {
        db.collection("users").addSnapshotListener { (querySnapshot, error) in
            guard let documents = querySnapshot?.documents else {
                print("No documents")
                return
            }
            
            self.users = documents.map { queryDocumentSnapshot -> Users in
                let data = queryDocumentSnapshot.data()
            
                let code_postal = data["code_postal"] as? String ?? ""
                let creatdAt = data["creatdAt"] as? String ?? ""
                let email = data["email"] as? String ?? ""
                let is_new = data["is_new"] as? String ?? ""
                let nom = data["nom"] as? String ?? ""
                let prenom = data["prenom"] as? String ?? ""
                let tel = data["tel"] as? String ?? ""
                let ville = data["ville"] as? String ?? ""

                
                return Users(id : .init(), code_postal: code_postal, creatdAt: creatdAt, email: email, is_new: is_new, nom: nom, prenom: prenom, tel: tel, ville: ville)
            }
        }
    }
}

这是我打印数据库的功能：

struct ProfileView: View {
    @ObservedObject private var viewModel = UsersViewModel()
    var body: some View {
        HStack(alignment: .top){
                List(viewModel.users) { users in
                    VStack(alignment: .leading) {
                            Section(header: Text("Prenom: ")) {
                                Text(users.prenom)
                            }
                            Section(header: Text ("Nom : ")) {
                                Text(users.nom)
                            }
                            Section(header: Text ("Ville : ")) {
                                Text(users.ville)
                            }
//                        Text ("Code postal : ")
//                        Text(users.code_postal)
//                            .font(.subheadline)
//                        Text ("Téléphone : ")
//                        Text(users.tel)
//                            .font(.subheadline)
//                        Text ("Email : ")
//                        Text(users.email)
//                            .font(.subheadline)
//                        Text ("Date d'inscription : ")
//                        Text(users.createdAt)
//                            .font(.subheadline)
                    }
                }
                .navigationBarTitle("News")
            }
            .onAppear() {
                self.viewModel.fetchDate()
            }
        Button(action: {
            try! Auth.auth().signOut()
            UserDefaults.standard.set(false, forKey: "status")
            NotificationCenter.default.post(name: NSNotification.Name("status"), object: nil)
        }, label: {
            Text("Déconnexion")
        })
    }
}

感谢您的帮助

Answer 1

您必须获取文档本身：

db.collection("users").document("userxyz789").addSnapshotListener { (docSnapshot, error) in
    ...
}

或在集合中查询：

db.collection("users").whereField("userId", isEqualTo: "userxyz789").addSnapshotListener { (querySnapshot, error) in
    ...
}

您当前正在做的是获取整个集合。