Flutter解析Accommodation模型返回空数组问题求助

问题概述 #

在GetX Controller中调用GET API，网络请求正常（返回200状态码），但解析Accommodation模型后得到空数组，预期应填充对应数据。

API调用代码 #

accommodationUpdateOrCreationDecision() async {
    List<Accommodation> accommdationModelsList = [];
  
    try {
      var headers = {
        "Authorization":
            "..u3nHlV7nZ5-BlGfoBb91of_RZ4W-Qn_tJOUwremWUA",
      };
      acTitleController.value.text = "hello world";
      var response = await _apiServices.getReq(
        endPoint: '${StringConstants.apiBaseUrl}/host/accommodation',
        headers: headers,
      );
      if (response.statusCode == 400) {
        log("Error Code ==> ${response.statusCode}");
      }
      log("Status Code ==> ${response.statusCode}");
      var accommDataModel = ApiResponseModel.fromJson(
        response.data,
      );
      if (accommDataModel.success == true) {
        accommadateUpdateDeleteBool.value = true;

        for (var data in response.data["data"]["accommodations"]) {
          Accommodation model = Accommodation.fromJson(data);
          accommdationModelsList.add(model);
        }

        log("response Model : ${accommdationModelsList}");
      } else {
        accommadateUpdateDeleteBool.value = false;
      }

      log("response Model success: ${accommDataModel.success.toString()}");
    } catch (e) {
      log("error : ${e.toString()}");
          }
  }

终端输出 #

[log] Status Code ==> 200
[log] response Model : []
[log] response Model success: true

核心问题代码段 #

for (var data in response.data["data"]["accommodations"]) {
  Accommodation model = Accommodation.fromJson(data);
  accommdationModelsList.add(model);
}

预期API响应 #

{
    "success": true,
    "data": {
        "message": "Accommodation fetched successfully",
        "baseUrl": "http://64.226.125.111/rev-be/uploads/",
        "accommodations": [
            {
                "location": {
                    "type": "Point",
                    "coordinates": [
                        67,
                        24
                    ]
                },
                "status": "Available",
                "_id": "64fc661abdd6042a77392b85",
                "host": "64e762462bbed117abce4cac",
                "title": "Updated Riverside Retreat",
                "desc": "Relax by the river at our tranquil retreat.",
                "images": [
                    "1695389483120-card-img-logo.png"
                ],
                "roomPrice": 2999,
                "dinnerPrice": 699,
                "roomCapacity": 12,
                "dinnerCapacity": 9,
                "services": [],
                "isActive": true,
                "createdAt": "2023-09-09T12:33:30.047Z",
                "updatedAt": "2023-09-22T13:31:23.121Z",
                "__v": 0,
                "reviewsId": [
                    "6501bc9189fcd2743e9d0e28",
                    "6501bca689fcd2743e9d0e2f"
                ],
                "rating": 3.7
            }
        ]
    }
}

解析模型代码 #

class Accommodation {
  final String? id;
  final String? host;
  final String? title;
  final String? desc;
  final List<String>? images;
  final int? roomPrice;
  final int? dinnerPrice;
  final Location? location;
  final int? roomCapacity;
  final int? dinnerCapacity;
  final List<dynamic>? services;
  final bool? isActive;
  final DateTime? createdAt;
  final DateTime? updatedAt;
  final int? v;
  final List<dynamic>? bookings;

  Accommodation({
    this.id,
    this.host,
    this.title,
    this.desc,
    this.images,
    this.roomPrice,
    this.dinnerPrice,
    this.location,
    this.roomCapacity,
    this.dinnerCapacity,
    this.services,
    this.isActive,
    this.createdAt,
    this.updatedAt,
    this.v,
    this.bookings,
  });

  factory Accommodation.fromJson(Map<String, dynamic> json) => Accommodation(
        id: json["_id"],
        host: json["host"],
        title: json["title"],
        desc: json["desc"],
        images: List<String>.from(json["images"].map((x) => "${StringConstants.imageBaseUrl}$x")),
        roomPrice: json["roomPrice"],
        dinnerPrice: json["dinnerPrice"],
        location: Location.fromJson(json["location"]),
        roomCapacity: json["roomCapacity"],
        dinnerCapacity: json["dinnerCapacity"],
        services: List<dynamic>.from(json["services"].map((x) => x)),
        isActive: json["isActive"],
        createdAt: DateTime.parse(json["createdAt"]),
        updatedAt: DateTime.parse(json["updatedAt"]),
        v: json["__v"],
        bookings: json["bookings"] == null
            ? []
            : List<dynamic>.from(json["bookings"]!.map((x) => x)),
      );

  Map<String, dynamic> toJson() => {
        "_id": id,
        "host": host,
        "title": title,
        "desc": desc,
        "images": List<dynamic>.from(images!.map((x) => x)),
        "roomPrice": roomPrice,
        "dinnerPrice": dinnerPrice,
        "location": location!.toJson(),
        "roomCapacity": roomCapacity,
        "dinnerCapacity": dinnerCapacity,
        "services": List<dynamic>.from(services!.map((x) => x)),
        "isActive": isActive,
        "createdAt": createdAt!.toIso8601String(),
        "updatedAt": updatedAt!.toIso8601String(),
        "__v": v,
        "bookings":
            bookings == null ? [] : List<dynamic>.from(bookings!.map((x) => x)),
      };
}

class Location {
  final String? type;
  final List<double>? coordinates;

  Location({
    this.type,
    this.coordinates,
  });

  factory Location.fromJson(Map<String, dynamic> json) => Location(
        type: json["type"],
        coordinates:
            List<double>.from(json["coordinates"].map((x) => x?.toDouble())),
      );

  Map<String, dynamic> toJson() => {
        "type": type,
        "coordinates": List<dynamic>.from(coordinates!.map((x) => x)),
      };
}

排查与解决步骤 #

1. 验证响应数据结构
   在循环前添加日志，打印response.data["data"]的完整内容，确认accommodations字段是否存在、字段名拼写是否正确：

   log("完整数据对象: ${response.data["data"]}");
   

2. 捕获解析异常
   当前try-catch未覆盖循环内的模型解析逻辑，若Accommodation.fromJson抛出异常会直接终止循环且无日志。修改代码添加局部捕获：

   for (var data in response.data["data"]["accommodations"]) {
     try {
       Accommodation model = Accommodation.fromJson(data);
       accommdationModelsList.add(model);
     } catch (parseError) {
       log("单条数据解析错误: ${parseError.toString()}");
     }
   }
   

   从预期JSON看，模型未包含status、reviewsId、rating字段，但这些为非必填项不会导致解析失败；需注意Location中整数转double的逻辑是否正常，以及images拼接的StringConstants.imageBaseUrl是否有效。

3. 统一数据来源
   既然已解析ApiResponseModel，直接从该模型获取数据，避免重复访问原始响应可能出现的不一致：

   // 需根据ApiResponseModel的实际结构调整data字段的访问方式
   for (var data in accommDataModel.data["accommodations"]) {
     Accommodation model = Accommodation.fromJson(data);
     accommdationModelsList.add(model);
   }
   

4. 检查ApiResponseModel的实现
   确认ApiResponseModel.fromJson未修改原始response.data，若模型对数据做了转换或过滤，会导致后续访问原始数据出现偏差。

内容的提问来源于stack exchange，提问作者Ali Jawad