Firebase Flutter Riverpod：在使用 Riverpod 跨模型映射值时，如何从 Firebase 获取 documentID？ 包含代码

Question

我需要在 firebase 集合中获取我的文档的 documentID。 documentID 不存储为文档中的字段。 该 ID 由 Firebase 在导入时选择。

其他字段，如姓名、电话、完整地址，都完美显示。 如何使用我的地图/模型访问自动生成的 docID？

非常感谢任何指导。

服务：

import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'restaurant_model.dart';

final restaurantProvider = StreamProvider.autoDispose((ref) {
  final service = ref.watch(restaurantServiceProvider);
  return service.restaurantModel();
});

final restaurantServiceProvider = Provider<RestaurantService>((ref) {
  final firebase = FirebaseFirestore.instance;
  return RestaurantService(firebase);
});

class RestaurantService {
  final FirebaseFirestore _firebase;
  
  RestaurantService(this._firebase);
  
  Stream<List<RestaurantModel>> restaurantModel() {
    return _firebase.collection('restaurantsPensacola').snapshots().map((event) => event.docs.map((e) => RestaurantModel.fromFirebase(e.data())).toList());
  }
}

模型

import 'package:cloud_firestore/cloud_firestore.dart';

class RestaurantModel {
  final String? name;
  final String? phone;
  final String? fullAddress;
  final String? yearsInBusiness;
  final String? priceRange;
  final String? websiteLink;
  final String? documentID;

  RestaurantModel({
    required this.name,
    required this.phone,
    required this.fullAddress,
    required this.yearsInBusiness,
    required this.priceRange,
    required this.websiteLink,
    required this.documentID,
});

  factory RestaurantModel.fromFirebase(Map<String, dynamic> restaurantModel) {

    return RestaurantModel(
        name: restaurantModel['name'],
        phone: restaurantModel['phone'],
        fullAddress: restaurantModel['fullAddress'],
        yearsInBusiness: restaurantModel['yearsInBusiness'],
        priceRange: restaurantModel['priceRange'],
        websiteLink: restaurantModel['websiteLink'],
        //THIS IS WHERE I AM LOST AS THIS GENERATES ERROR
        //Instance members can't be accessed from a factory constructor.
        documentID: restaurantModel[documentID],
    );
  }
}

Answer 1

可以通过e.id访问文档 ID。 对于您的 RestaurantModel，您可能希望将其重命名为restaurantId以使其描述的内容更加准确，并且只需在创建时将自动生成的文档 ID 保存为 restaurantId。 您还可以生成自己的唯一 ID（使用 uuid 包或类似的东西）并使用该 ID 创建一个新文档。

例子：

    Future<dynamic> createRestaurantRecord(
      String id, Map<String, dynamic> data) async {
    return await _firestore.doc('restaurants/$id').set(data);
    }

您的工厂将无法工作，因为文档 ID 不会自动与文档的其余数据一起存储。

Answer 2

我能够与我的导师会面，并被告知我可以通过在 e.data 之后添加 e.id 从 Firebase 获取 ID。

    Stream<List<RestaurantModel>> restaurantModel() {
    return _firebase.collection('restaurantsPensacola').snapshots().map(
        (event) => event.docs.map((e) => RestaurantModel.fromFirebase(e.data(), e.id)).toList());
  }

然后，建议我稍微更改名称以更容易区分值。 您将看到我是如何从 Firebase 合并 documentID 的。

import 'package:cloud_firestore/cloud_firestore.dart';

class RestaurantModel {
  final String? name;
  final String? phone;
  final String? fullAddress;
  final String? yearsInBusiness;
  final String? priceRange;
  final String? websiteLink;
  final String? id;

  RestaurantModel({
    required this.name,
    required this.phone,
    required this.fullAddress,
    required this.yearsInBusiness,
    required this.priceRange,
    required this.websiteLink,
    required this.id,
  });

  factory RestaurantModel.fromFirebase(
      Map<String, dynamic> restaurantModel, String documentIDFromFirebase) {
    return RestaurantModel(
      name: restaurantModel['name'],
      phone: restaurantModel['phone'],
      fullAddress: restaurantModel['fullAddress'],
      yearsInBusiness: restaurantModel['yearsInBusiness'],
      priceRange: restaurantModel['priceRange'],
      websiteLink: restaurantModel['websiteLink'],
      id: documentIDFromFirebase,
    );
  }
}