错误：类型 '(dynamic) =>Meta' 不是类型 '(String, dynamic) => MapEntry<dynamic, dynamic>' of 'transform' 的子类型

Question

这是我的 json：

{
  "data": {
    "id": 1,
    "title": "Test-1",
    "description": "Description of test-1.",
    "category_id": "1",
    "product_sizes": [
      {
        "id": 24,
        "name": "name",
        "created_at": "2021-06-28T09:50:12.000000Z",
        "updated_at": "2021-06-28T09:50:12.000000Z",
        "pivot": {
          "product_id": "1",
          "size_id": "24"
        }
      }
    ],
    "stock_images": [
      {
        "id": 13,
        "product_id": "1",
        "stock_id": "109",
        "color_id": "1",
        "meta": {
          "small": "image_path",
          "medium": "image_path",
          "large": "image_path"
        },
      },
      {
        "id": 14,
        "product_id": "1",
        "stock_id": "110",
        "color_id": "2",
        "meta": {
          "small": "image_path",
          "medium": "image_path",
          "large": "image_path"
        },
      },
     
    ],
    "category": {
      "id": 27,
      "title": "Category_title",
    }
  },
}

我的api调用如下：

static Future<Test> getTest(int id) async{
    final response = await client.get(Uri.parse("URL_HERE"));
    if(response.statusCode == 200){
      Map<String, dynamic> json = jsonDecode(response.body);
      dynamic body = json['data'];
      Test test = Test.fromJson(body);
      return test;
    }
    else{
      throw("Couldnot get product detail from the server");
    }
  }

下面是模型类：

class Test {
  final int id;
  final String title;
  final String description;
  final List<StockImage>? stockImages;

Test({
    required this.id,
    required this.title,
    required this.description,
    required this.stockimages
});

factory Test.fromJson(Map<String, dynamic> parsedJson) {
return Test(
       id: parsedJson["id"],
       title: parsedJson["title"],
       stockImages: List<StockImage>.from(parsedJson["stock_images"].map((l)=> 
       StockImage.fromJson(l))),

);
  }
}

class StockImage {
  final int id;
  final String productId;
  final String stockId;
  final String colorId;
  final List<Meta>? meta;
StockImage({
    required this.id,
    required this.productId,
    required this.stockId,
    required this.colorId,
     this.meta,
  });
 factory StockImage.fromJson(Map<dynamic, dynamic> json){
  return StockImage(
      id : json["id"] as int,
      productId : json["product_id"] as String,
      stockId : json["stock_id"] as String,
      colorId : json["color_id"] as String, 
      meta: List<Meta>.from(json["meta"].map((l)=>Meta.fromJson(l))),
 );}
}

class Meta{
  final String small;
  final String medium;
  final String large;

  Meta({
    required this.small,
    required this.medium,
    required this.large
  });


  factory Meta.fromJson(Map<String, dynamic> json) {
    return Meta(
        small : json['small'] as String,
        medium : json['medium'] as String,
        large : json['large'] as String
    );}

}

我不确定我是否采用了有效的方法来创建模型类，但请就我的问题向我提问，因为我可能遗漏了一些东西。我正在尝试从 Meta 类中获取图像列表。提前谢谢！

Answer 1

你可以试试这个

class Meta{
  final String small;
  final String medium;
  final String large;

  Meta({
    required this.small,
    required this.medium,
    required this.large
  });


  factory Meta.fromJson(Map<dynamic, dynamic> json) {
    return Meta(
        small : json['small'] as String,
        medium : json['medium'] as String,
        large : json['large'] as String
    );}

}