Flutter - 映射 JSON

Posted 2023-04-14

【中文标题】Flutter - 映射 JSON

【英文标题】：Flutter - Map JSON

【发布时间】：2020-05-20 20:42:02

【问题描述】：

我是 DART / FLUTER 的新手，仍然有很多困难。我有一个注册功能，我需要返回 Json MAP 中的 2 个属性。构造下面的函数但返回错误

[错误：flutter/lib/ui/ui_dart_state.cc(157)]未处理异常：类型_InternalLinkedHashMap'不是List类型的子类型

你能帮帮我吗？

关于我的代码：

    saveClient(Cliente cliente) async 
      final Map<String, dynamic> clienteMap = 
        "nome": cliente.nome,
        "email": cliente.email,
        "senha": cliente.senha,
        "celular": cliente.celular,
      ;

      final String clientJson = jsonEncode(clienteMap);
      client.post(baseUrl + '/usuario',
          headers: 'Content-type': 'application/json', 'password': 'admin',
          body: clientJson);


      final Response response = await client.get(baseUrl + '/usuario/id');
      final List<dynamic> decodedJson = jsonDecode(response.body);
      final List<ClienteDto> dataUser = List();
      for (Map<String, dynamic> clienteJson in decodedJson) 
        final ClienteDto cliente = ClienteDto(
          clienteJson['id'],
          clienteJson['nome'],
        );
        dataUser.add(cliente);
        print(dataUser);
      
      return dataUser;
    

【问题讨论】：

您在哪一行收到此错误？没有更多细节很难给出答案。

这一行：final List decodedJson = jsonDecode(response.body);

【参考方案1】：

您正在尝试将解码后的 JSON 响应（Map）分配给无效分配的 List。您应该尝试打印jsonDecode(response.body) 的结果，以找出您关心的结果的实际部分在响应中的位置。

【讨论】：

对不起，正如我所说，我是 Dart 语言的新手，我在 2 周前才开始使用它。代码中的打印只是为了测试目的。我真正需要的是将作为注册数据发送的 [id] 和 [nome] 的值分配给一个变量。我怎样才能做到这一点？

没问题，我很乐意提供帮助。你能分享jsonDecode(response.body)的输出吗？

只是提醒@Hudson_Nunes - 你没有更新你的帖子，你添加了一个更新来回答你的问题。您应该获取其他内容并将其添加到您的问题中，因为它不是您问题的有效答案。

+1 到 BJHStudios 评论。此外，您似乎没有发出有效的请求，因此您的响应正文包含错误。

感谢您的评论。我会在另一篇文章中重新提出我的问题。

【参考方案2】：

这是我的 WebClient 类的所有代码：

import 'dart:async';
import 'dart:convert';
import 'package:http/http.dart';
import 'package:http_interceptor/http_interceptor.dart';
import 'package:owlwee/Models/Cartao.dart';
import 'package:owlwee/Models/Cliente.dart';
import 'package:owlwee/Models/ClienteDto.dart';

final Client client =
    HttpClientWithInterceptor.build(interceptors: [LoggingInterceptor()]);

const String baseUrl = 'http://xxxxxxxxxxxxxx:8080'; // LEROMA
const String baseUrlCheckIn = 'http://xxxxxxxxxxxxx:8081'; // LEROMA


class LoggingInterceptor implements InterceptorContract 
  @override
  Future<RequestData> interceptRequest(RequestData data) async 
    print('Request');
    print('Headers: $data.headers');
    print('body: $data.body');
    return data;
  

  @override
  Future<ResponseData> interceptResponse(ResponseData data) async 
    print('Status $data.statusCode');
    print('Headers: $data.headers');
    print('body: $data.body');
    return data;
  


saveClient(Cliente cliente) async 
  final Map<String, dynamic> clienteMap = 
    "nome": cliente.nome,
    "email": cliente.email,
    "senha": cliente.senha,
    "celular": cliente.celular,
  ;

  final String clientJson = jsonEncode(clienteMap);
  client.post(baseUrl + '/usuario',
      headers: 'Content-type': 'application/json', 'password': 'admin',
      body: clientJson);


  final Response response = await client.get(baseUrl + '/usuario/id');
  final List<dynamic> decodedJson = jsonDecode(response.body);
  final List<ClienteDto> dataUser = List();
  for (Map<String, dynamic> clienteJson in decodedJson) 
    final ClienteDto cliente = ClienteDto(
      clienteJson['id'],
      clienteJson['nome'],
    );
    dataUser.add(cliente);
    print(dataUser);
  
  return dataUser;

这是控制台的答案：

√ Built build\app\outputs\apk\debug\app-debug.apk.
Installing build\app\outputs\apk\app.apk...
Syncing files to device android SDK built for x86...
I/flutter (15631): Request
I/flutter (15631): Headers: Content-type: application/json; charset=utf-8, password: admin
I/flutter (15631): body: "nome":"Hudson","email":"[e-mail]","senha":"123456","celular":21987987987
I/flutter (15631): Request
I/flutter (15631): Headers: 
I/flutter (15631): body: 
I/flutter (15631): Status 400
I/flutter (15631): Headers: connection: close, content-type: application/json, date: Wed, 05 Feb 2020 00:38:37 GMT, transfer-encoding: chunked
I/flutter (15631): body: "timestamp":"2020-02-05T00:38:37.040+0000","status":400,"error":"Bad Request","message":"Failed to convert value of type 'java.lang.String' to required type 'int'; nested exception is java.lang.NumberFormatException: For input string: \"id\"","trace":"org.springframework.web.method.annotation.MethodArgumentTypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'int'; nested exception is java.lang.NumberFormatException: For input string: \"id\"\r\n\tat org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver.resolveArgument(AbstractNamedValueMethodArgumentResolver.java:133)\r\n\tat org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:167)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(Invocable
E/flutter (15631): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'List<dynamic>'
E/flutter (15631): #0      saveClient (package:owlwee/http/webclient.dart:83:23)
E/flutter (15631): <asynchronous suspension>
E/flutter (15631): #1      _CadastroState.build.<anonymous closure> (package:owlwee/Views/Cadastro.dart:192:25)
E/flutter (15631): #2      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:706:14)
E/flutter (15631): #3      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:789:36)
E/flutter (15631): #4      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter (15631): #5      TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:486:11)
E/flutter (15631): #6      BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:264:5)
E/flutter (15631): #7      BaseTapGestureRecognizer.acceptGesture (package:flutter/src/gestures/tap.dart:236:7)
E/flutter (15631): #8      GestureArenaManager.sweep (package:flutter/src/gestures/arena.dart:156:27)
E/flutter (15631): #9      GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:222:20)
E/flutter (15631): #10     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
E/flutter (15631): #11     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
E/flutter (15631): #12     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
E/flutter (15631): #13     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
E/flutter (15631): #14     _rootRunUnary (dart:async/zone.dart:1138:13)
E/flutter (15631): #15     _CustomZone.runUnary (dart:async/zone.dart:1031:19)
E/flutter (15631): #16     _CustomZone.runUnaryGuarded (dart:async/zone.dart:933:7)
E/flutter (15631): #17     _invoke1 (dart:ui/hooks.dart:273:10)
E/flutter (15631): #18     _dispatchPointerDataPacket (dart:ui/hooks.dart:182:5)
E/flutter (15631): 
I/flutter (15631): Status 201
I/flutter (15631): Headers: content-type: application/json, location: http://192.168.1.9:8080/usuario/9, date: Wed, 05 Feb 2020 00:38:37 GMT, transfer-encoding: chunked
I/flutter (15631): body: "id":9,"nome":"Hudson"

这是你问的吗？