json - 从 JSON 映射模型在映射 int 值时给我一个错误

Question

您好，我正在尝试从 JSOn 获取值，但是当我映射一个 INT 值时，flutter 显示该错误并且没有返回数据:

flutter: type 'String' is not a subtype of type 'int'

这是我的模型:

import 'package:http/http.dart' as http;
import 'dart:async';
import 'dart:convert';


class Kits {

  final String country;
  final String franchise;
  final String type;
   String brand;
   String procedure;
   String setdesc;
   int traymaterialid;
   String traydesc;
   int referencia;
   String descart;
   int cantidad;
   int homologado;
   int bajopresu;
   DateTime insdate;


   Kits(this.country,this.franchise,this.type, this.brand, this.procedure,this.traydesc, this.traymaterialid);

  factory Kits.fromJson(Map<String, dynamic>  json) {
         return Kits(json['COUNTRY'], json['FRANCHISE'], json['TYPE'], json['BRAND'], json['PROCEDURE'], json['TRAYDESCRIPTION'], json['TRAYMATERIALID'] /* <-- INT*/ );
  }

}

class KitsData {

  static const url = 'http://app-smith.com/en/kits_API.php?email=miquel@winfor.es&macid=888&passwd=Wcz95f4UGkax5G';
  final JsonDecoder _decoder = new JsonDecoder();

    Future<List<Kits>> fetch(){    
  return http.get(url).then((http.Response response){
    final String jsonBody = response.body;
    //final statusCode = response.statusCode;

      /*if (statusCode < 200 || statusCode >= 300 || jsonBody == null){ 
        return List();
      }*/

      final kitsContainer = _decoder.convert(jsonBody);
      final List kitsItems = kitsContainer['kits'];

      return kitsItems.map( (kitsRaw) => new Kits.fromJson(kitsRaw) ).toList();

    });

  } 

}

class FetchDataException implements Exception {
  String _message;

  FetchDataException(this._message);

  String toString() {
    return "Exception: $_message";
  }
}

我不明白为什么会这样，因为 fromJson 只获取我传递的值，然后在我的列表中我将值转换为字符串。

JSON 片段:

{"kits": [{"COUNTRY":"FR","FRANCHISE":"KNEE","TYPE":"LEGION","BRAND":"REVISION","PROCEDURE":"LEGION REVISION","SETDESCRIPTION":"LEGION REVISION - INSTRUMENTS","TRAYMATERIALID":"551820141LRC","TRAYDESCRIPTION":"INSTR LEGION REVISION","REFERENCIA":"71431722","DESCRIPCIONARTICULO":"LGN SCW LWDG TRL S3 5D X 10P","CANTIDAD":"1","HOMOLOGADO":"","BAJOPRESUPUESTO":"","INS_DATE":"2018-08-23 18:57:04"}

Answer 1

所有数值都在引号内，因此它们不是作为 int 而是作为 String 传输的。错误信息是正确的。如果您希望它们作为 String 要么确保值不被引用，如果您不控制使用 int.parse() 将它们从 String< 转换 到 int