android - 在 flutter 上解析 json 时出错。类型 '_InternalLinkedHashMap' 不是类型转换中类型 'ResultData' 的子类型

Question

我有如下的 json。

{  
   "result_data":{  
      "id":"b57457b0-4f73-11e8-92ae-01912016d38c",
      "rates":[  
         {  },
         {  }
      ]
   }
}

我想解析，下面是我解析它的代码。获取“result_data”

class RootModel {
  ResultData resultData;

  RootModel(this.resultData);

  RootModel.fromJSON(Map<String, dynamic> response) {
    var list = response['result_data'] as ResultData;
    print(list.runtimeType);
  }
}

解析结果数据对象。

class ResultData {
  String id;
  List<Rate> rates;
  ResultData(this.id, this.rates);

  ResultData.fromJSON(Map<String, dynamic> parsedJson) {
    this.id = parsedJson['id'] as String;
    this.rates = (parsedJson['rates'] as List)
        .map((json) => Rate.fromJSON(json))
        .toList();
  }
}

进一步的费率模型还有其他模型和模型列表。我得到的上述代码的错误是:

 E/flutter: [ERROR:flutter/shell/common/shell.cc(184)] Dart Error: Unhandled exception:
    type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'ResultData' in type cast
    #0      new RootModel.fromJSON (package:movies_streams/models/RootModel.dart:16:40)

Answer 1

您不能将 map 转换到 ResultData。

class RootModel {
  ResultData resultData;

  RootModel(this.resultData);

  RootModel.fromJSON(Map<String, dynamic> response) {
//    var list = response['result_data'] as ResultData;
    var list = ResultData.fromJSON(response['result_data']);
    print(list.runtimeType);
  }
}