Flutter 从地图中获取数据 API

Question

你好，我是 Flutter 的新手，我需要使用 API 从地图中获取数据我现在正在苦苦挣扎，不知道该怎么做我总是不断收到错误 Error '_InternalLinkedHashMap' 不是 'Iterable' 类型的子类型这是 class 代码

// To parse this JSON data, do
//
//     final aziz = azizFromJson(jsonString);

import 'dart:convert';

Demandes azizFromJson(String str) => Demandes.fromJson(json.decode(str));

String azizToJson(Demandes data) => json.encode(data.toJson());

class Demandes {
  Demandes({
    required this.srMboSet,
  });

  SrMboSet srMboSet;

  factory Demandes.fromJson(Map<String, dynamic> json) => Demandes(
        srMboSet: SrMboSet.fromJson(json["SRMboSet"]),
      );

  Map<String, dynamic> toJson() => {
        "SRMboSet": srMboSet.toJson(),
      };
}

class SrMboSet {
  SrMboSet({
    required this.rsStart,
    required this.rsCount,
    required this.sr,
  });

  int rsStart;
  int rsCount;
  List<Sr> sr;

  factory SrMboSet.fromJson(Map<String, dynamic> json) => SrMboSet(
        rsStart: json["rsStart"],
        rsCount: json["rsCount"],
        sr: List<Sr>.from(json["SR"].map((x) => Sr.fromJson(x))),
      );

  Map<String, dynamic> toJson() => {
        "rsStart": rsStart,
        "rsCount": rsCount,
        "SR": List<dynamic>.from(sr.map((x) => x.toJson())),
      };
}

class Sr {
  Sr({
    required this.rowstamp,
    required this.attributes,
  });

  String rowstamp;
  Attributes attributes;

  factory Sr.fromJson(Map<String, dynamic> json) => Sr(
        rowstamp: json["rowstamp"],
        attributes: Attributes.fromJson(json["Attributes"]),
      );

  Map<String, dynamic> toJson() => {
        "rowstamp": rowstamp,
        "Attributes": attributes.toJson(),
      };
}

class Attributes {
  Attributes({
    required this.ticketid,
    required this.attributesClass,
    required this.description,
    required this.status,
    required this.statusdate,
    required this.reportedby,
  });

  Class ticketid;
  Class attributesClass;
  Class description;
  Class status;
  Class statusdate;
  Class reportedby;

  factory Attributes.fromJson(Map<String, dynamic> json) => Attributes(
        ticketid: Class.fromJson(json["TICKETID"]),
        attributesClass: Class.fromJson(json["CLASS"]),
        description: Class.fromJson(json["DESCRIPTION"]),
        status: Class.fromJson(json["STATUS"]),
        statusdate: Class.fromJson(json["STATUSDATE"]),
        reportedby: Class.fromJson(json["REPORTEDBY"]),
      );

  Map<String, dynamic> toJson() => {
        "TICKETID": ticketid.toJson(),
        "CLASS": attributesClass.toJson(),
        "DESCRIPTION": description.toJson(),
        "STATUS": status.toJson(),
        "STATUSDATE": statusdate.toJson(),
        "REPORTEDBY": reportedby.toJson(),
      };
}

class Class {
  Class({
    required this.content,
  });

  String content;

  factory Class.fromJson(Map<String, dynamic> json) => Class(
        content: json["content"],
      );

  Map<String, dynamic> toJson() => {
        "content": content,
      };
}

这是我的主要代码，如果有人可以提供帮助，我总是会出错

// ignore_for_file: use_key_in_widget_constructors, avoid_print, avoid_unnecessary_containers, curly_braces_in_flow_control_structures, prefer_const_constructors, non_constant_identifier_names, unnecessary_new, avoid_function_literals_in_foreach_calls
import 'dart:convert';
import './demandes.dart';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: DataFromAPI(),
    );
  }
}

class DataFromAPI extends StatefulWidget {
  @override
  _DataFromAPIState createState() => _DataFromAPIState();
}

class _DataFromAPIState extends State<DataFromAPI> {
  List<Attributes> MyAllData = [];
  @override
  void initState() {
    loadData();
  }

  loadData() async {
    var response = await http.get(Uri.parse(
        'http://192.168.1.30:9080/maxrest/rest/mbo/sr/?_lid=&_lpwd=&_format=json'));
    if (response.statusCode == 200) {
      String responseBody = response.body;
      Map<String, dynamic> jsonBody = json.decode(responseBody);
      for (var data in jsonBody) {
        MyAllData.add(Attributes(
            ticketid: data["ticketid"],
            attributesClass: data["attributesClass"],
            description: data["description"],
            status: data["status"],
            statusdate: data["statusdate"],
            reportedby: data["reportedby"]));
      }
      setState(() {
        MyAllData.forEach((somedata) => print("Name: ${somedata.ticketid}"));
      });
    } else {
      print("theres something wrong...");
    }
  }

  Widget build(BuildContext context) {
    return MaterialApp(
      home: new Scaffold(
        appBar: AppBar(
          title: Text('Liste des SR'),
        ),
        body: MyAllData.length == 0
            ? new Center(
                child: new CircularProgressIndicator(),
              )
            : showMyUI(),
      ),
    );
  }

  Widget showMyUI() {
    return new ListView.builder(
        itemCount: MyAllData.length,
        itemBuilder: ((_, index) {
          return new Container(
            child: new Card(
              child: new Container(
                child: new Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    new Text(
                      'Ticket ID : ${MyAllData[index].ticketid}',
                    ),
                  ],
                ),
              ),
            ),
          );
        }));
  }
}

Answer 1

所以从你的模型 class，我看到你在 Sr 里面有 Attributes，但是在你的 JSON 解码之后，你继续将数据添加到属性列表，所以这就是你的错误来源，你没有完全反序列化数据这里是你如何做到的并且它会起作用

      loadData() async {
        var response = await http.get(Uri.parse(
            'http://192.168.1.30:9080/maxrest/rest/mbo/sr/?_lid=&_lpwd=&_format=json'));
        if (response.statusCode == 200) {
          final jsonBody = json.decode(response.body);
Demandes data = Demandes.fromJson(jsonBody);
final srAttributes = data.srMboSet.sr;
// SR is your list attributes is just an object, So what you do is this 
          for (int attribute = 0; attribute  < srAttributes.length; attribute++) {
MyAllData.add(srAttributes[attribute].attributes);

          }
          setState(() {
            MyAllData.forEach((somedata) => print("Name: ${somedata.ticketid}"));
          });
        } else {
          print("theres something wrong...");
        }
      }

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