json - Flutter错误类 'StudyList'没有实例方法 '[]'

Question

我正在尝试将JSON数组解析为我的应用程序中的List，它可以与其他模型类一起使用，但仅此特定类会出现错误。我在其他情况下也使用过类似的代码，但是在这里不起作用。如果仅使用列表而不是将类型更改为模型类，然后启动响应，则它将起作用。

════════ Exception caught by widgets library ═══════════════════════════════════════════════════════
Class 'StudyList' has no instance method '[]'.
Receiver: Instance of 'StudyList'
Tried calling: []("reportStatus")
════════════════════════════════════════════════════════════════════════════════════════════════════

这是我的模型课:

class StudyList {
  String studyUID;
  String patientId;
  String patientName;
  String studyDateTime;
  String modalityName;
  String study;
  String studyDescription;
  String refferringPhysician;
  String clinicalHistory;
  String siteName;
  String reportPath;
  String attachmentPath;
  String imageReceviedTime;
  var reportReceviedTime;
  int noOfImages;
  String reportStatus;
  String radiologistName;
  String gender;
  String age;
  int series;
  int siteID;
  int radiologistID;
  var reportReceviedTime1;
  String radiologistAssignedTime;
  int radcentreId;
  String examdate;
  int emergencyst;
  String studycode;
  var repdown;
  String thumbnail;
  int modality;
  int status;
  var studyview;
  var studydown;

  StudyList(
      {this.studyUID,
        this.patientId,
        this.patientName,
        this.studyDateTime,
        this.modalityName,
        this.study,
        this.studyDescription,
        this.refferringPhysician,
        this.clinicalHistory,
        this.siteName,
        this.reportPath,
        this.attachmentPath,
        this.imageReceviedTime,
        this.reportReceviedTime,
        this.noOfImages,
        this.reportStatus,
        this.radiologistName,
        this.gender,
        this.age,
        this.series,
        this.siteID,
        this.radiologistID,
        this.reportReceviedTime1,
        this.radiologistAssignedTime,
        this.radcentreId,
        this.examdate,
        this.emergencyst,
        this.studycode,
        this.repdown,
        this.thumbnail,
        this.modality,
        this.status,
        this.studyview,
        this.studydown});

  StudyList.fromJson(Map<String, dynamic> json) {
    studyUID = json['studyUID'];
    patientId = json['patientId'];
    patientName = json['patientName'];
    studyDateTime = json['studyDateTime'];
    modalityName = json['modalityName'];
    study = json['study'];
    studyDescription = json['studyDescription'];
    refferringPhysician = json['refferringPhysician'];
    clinicalHistory = json['clinicalHistory'];
    siteName = json['siteName'];
    reportPath = json['reportPath'];
    attachmentPath = json['attachmentPath'];
    imageReceviedTime = json['imageReceviedTime'];
    reportReceviedTime = json['reportReceviedTime'];
    noOfImages = json['noOfImages'];
    reportStatus = json['reportStatus'];
    radiologistName = json['radiologistName'];
    gender = json['gender'];
    age = json['age'];
    series = json['series'];
    siteID = json['siteID'];
    radiologistID = json['radiologistID'];
    reportReceviedTime1 = json['reportReceviedTime1'];
    radiologistAssignedTime = json['radiologistAssignedTime'];
    radcentreId = json['radcentreId'];
    examdate = json['examdate'];
    emergencyst = json['emergencyst'];
    studycode = json['studycode'];
    repdown = json['repdown'];
    thumbnail = json['thumbnail'];
    modality = json['modality'];
    status = json['status'];
    studyview = json['studyview'];
    studydown = json['studydown'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['studyUID'] = this.studyUID;
    data['patientId'] = this.patientId;
    data['patientName'] = this.patientName;
    data['studyDateTime'] = this.studyDateTime;
    data['modalityName'] = this.modalityName;
    data['study'] = this.study;
    data['studyDescription'] = this.studyDescription;
    data['refferringPhysician'] = this.refferringPhysician;
    data['clinicalHistory'] = this.clinicalHistory;
    data['siteName'] = this.siteName;
    data['reportPath'] = this.reportPath;
    data['attachmentPath'] = this.attachmentPath;
    data['imageReceviedTime'] = this.imageReceviedTime;
    data['reportReceviedTime'] = this.reportReceviedTime;
    data['noOfImages'] = this.noOfImages;
    data['reportStatus'] = this.reportStatus;
    data['radiologistName'] = this.radiologistName;
    data['gender'] = this.gender;
    data['age'] = this.age;
    data['series'] = this.series;
    data['siteID'] = this.siteID;
    data['radiologistID'] = this.radiologistID;
    data['reportReceviedTime1'] = this.reportReceviedTime1;
    data['radiologistAssignedTime'] = this.radiologistAssignedTime;
    data['radcentreId'] = this.radcentreId;
    data['examdate'] = this.examdate;
    data['emergencyst'] = this.emergencyst;
    data['studycode'] = this.studycode;
    data['repdown'] = this.repdown;
    data['thumbnail'] = this.thumbnail;
    data['modality'] = this.modality;
    data['status'] = this.status;
    data['studyview'] = this.studyview;
    data['studydown'] = this.studydown;
    return data;
  }
}

这是我用于解析API中数据的代码:

List<StudyList> _patientDataapi = List();

setState(() {
             _shimmerLoader = true;
           

             _patientDataapi = (json.decode(res.body))
               .map<StudyList>((item) => StudyList.fromJson(item))
               .toList();
             
           });

最后，这是在制作API时获取的JSON数据:

[
    {
        "studyUID": "1.2.840.113619.2.55.3.2831168001.314.1602949790.991",
        "patientId": "4789",
        "patientName": "MR.ANIKET ADKAKE",
        "studyDateTime": "2020-10-17T22:22:04",
        "modalityName": "CT",
        "study": "NECK PLAIN",
        "studyDescription": "CT-NECK",
        "refferringPhysician": "G.H.S",
        "clinicalHistory": "H/O- LOSS OF VOICE",
        "siteName": "Aditya sangli",
        "reportPath": "",
        "attachmentPath": "",
        "imageReceviedTime": "2020-10-17T22:24:49",
        "reportReceviedTime": null,
        "noOfImages": 215,
        "reportStatus": "Pending",
        "radiologistName": "Dr.Agarwal",
        "gender": "M",
        "age": "026Y",
        "series": 5,
        "siteID": 209,
        "radiologistID": 518,
        "reportReceviedTime1": null,
        "radiologistAssignedTime": "2020-10-17T22:48:00",
        "radcentreId": 6,
        "examdate": "2020-10-17T21:38:57",
        "emergencyst": 0,
        "studycode": "CT-21",
        "repdown": null,
        "thumbnail": "",
        "modality": 1,
        "status": 3,
        "studyview": null,
        "studydown": null
    },
    {
        "studyUID": "1.2.840.113619.2.55.3.2831168001.314.1602949791.126",
        "patientId": "CT-4792",
        "patientName": "MR.ANIKET ADAKE",
        "studyDateTime": "2020-10-17T23:49:32",
        "modalityName": "CT",
        "study": "NECK PLAIN",
        "studyDescription": "CT-NECK PLAIN",
        "refferringPhysician": "G.H.S",
        "clinicalHistory": "H/O- LOSS OF VOICE",
        "siteName": "Aditya sangli",
        "reportPath": "C:\\KINSOLUTIONS\\Team\\Report\\1.2.840.113619.2.55.3.2831168001.314.1602949791.126.docx",
        "attachmentPath": "",
        "imageReceviedTime": "2020-10-17T23:50:29",
        "reportReceviedTime": null,
        "noOfImages": 273,
        "reportStatus": "Final",
        "radiologistName": "Dr.Agarwal",
        "gender": "M",
        "age": "025Y",
        "series": 4,
        "siteID": 209,
        "radiologistID": 518,
        "reportReceviedTime1": "2020-10-18T00:25:07",
        "radiologistAssignedTime": "2020-10-17T23:52:08",
        "radcentreId": 6,
        "examdate": "2020-10-17T23:46:03",
        "emergencyst": 0,
        "studycode": "CT-21",
        "repdown": true,
        "thumbnail": "",
        "modality": 1,
        "status": 5,
        "studyview": null,
        "studydown": null
    }
]

Answer 1

这是您提供的json:

[
    {
        "studyUID": "1.2.840.113619.2.55.3.2831168001.314.1602949790.991",
        "patientId": "4789",
        "patientName": "MR.ANIKET ADKAKE",
        "studyDateTime": "2020-10-17T22:22:04",
        "modalityName": "CT",
        "study": "NECK PLAIN",
        "studyDescription": "CT-NECK",
        "refferringPhysician": "G.H.S",
        "clinicalHistory": "H/O- LOSS OF VOICE",
        "siteName": "Aditya sangli",
        "reportPath": "",
        "attachmentPath": "",
        "imageReceviedTime": "2020-10-17T22:24:49",
        "reportReceviedTime": null,
        "noOfImages": 215,
        "reportStatus": "Pending",
        "radiologistName": "Dr.Agarwal",
        "gender": "M",
        "age": "026Y",
        "series": 5,
        "siteID": 209,
        "radiologistID": 518,
        "reportReceviedTime1": null,
        "radiologistAssignedTime": "2020-10-17T22:48:00",
        "radcentreId": 6,
        "examdate": "2020-10-17T21:38:57",
        "emergencyst": 0,
        "studycode": "CT-21",
        "repdown": null,
        "thumbnail": "",
        "modality": 1,
        "status": 3,
        "studyview": null,
        "studydown": null
    },
    {
        "studyUID": "1.2.840.113619.2.55.3.2831168001.314.1602949791.126",
        "patientId": "CT-4792",
        "patientName": "MR.ANIKET ADAKE",
        "studyDateTime": "2020-10-17T23:49:32",
        "modalityName": "CT",
        "study": "NECK PLAIN",
        "studyDescription": "CT-NECK PLAIN",
        "refferringPhysician": "G.H.S",
        "clinicalHistory": "H/O- LOSS OF VOICE",
        "siteName": "Aditya sangli",
        "reportPath": "C:\\KINSOLUTIONS\\Team\\Report\\1.2.840.113619.2.55.3.2831168001.314.1602949791.126.docx",
        "attachmentPath": "",
        "imageReceviedTime": "2020-10-17T23:50:29",
        "reportReceviedTime": null,
        "noOfImages": 273,
        "reportStatus": "Final",
        "radiologistName": "Dr.Agarwal",
        "gender": "M",
        "age": "025Y",
        "series": 4,
        "siteID": 209,
        "radiologistID": 518,
        "reportReceviedTime1": "2020-10-18T00:25:07",
        "radiologistAssignedTime": "2020-10-17T23:52:08",
        "radcentreId": 6,
        "examdate": "2020-10-17T23:46:03",
        "emergencyst": 0,
        "studycode": "CT-21",
        "repdown": true,
        "thumbnail": "",
        "modality": 1,
        "status": 5,
        "studyview": null,
        "studydown": null
    }
]

这是上述json的更新的模型类:

// To parse this JSON data, do
//
//     final studyList = studyListFromJson(jsonString);

import 'dart:convert';

List<StudyList> studyListFromJson(String str) => List<StudyList>.from(json.decode(str).map((x) => StudyList.fromJson(x)));

String studyListToJson(List<StudyList> data) => json.encode(List<dynamic>.from(data.map((x) => x.toJson())));

class StudyList {
    StudyList({
        this.studyUid,
        this.patientId,
        this.patientName,
        this.studyDateTime,
        this.modalityName,
        this.study,
        this.studyDescription,
        this.refferringPhysician,
        this.clinicalHistory,
        this.siteName,
        this.reportPath,
        this.attachmentPath,
        this.imageReceviedTime,
        this.reportReceviedTime,
        this.noOfImages,
        this.reportStatus,
        this.radiologistName,
        this.gender,
        this.age,
        this.series,
        this.siteId,
        this.radiologistId,
        this.reportReceviedTime1,
        this.radiologistAssignedTime,
        this.radcentreId,
        this.examdate,
        this.emergencyst,
        this.studycode,
        this.repdown,
        this.thumbnail,
        this.modality,
        this.status,
        this.studyview,
        this.studydown,
    });

    String studyUid;
    String patientId;
    String patientName;
    DateTime studyDateTime;
    String modalityName;
    String study;
    String studyDescription;
    String refferringPhysician;
    String clinicalHistory;
    String siteName;
    String reportPath;
    String attachmentPath;
    DateTime imageReceviedTime;
    dynamic reportReceviedTime;
    int noOfImages;
    String reportStatus;
    String radiologistName;
    String gender;
    String age;
    int series;
    int siteId;
    int radiologistId;
    DateTime reportReceviedTime1;
    DateTime radiologistAssignedTime;
    int radcentreId;
    DateTime examdate;
    int emergencyst;
    String studycode;
    bool repdown;
    String thumbnail;
    int modality;
    int status;
    dynamic studyview;
    dynamic studydown;

    factory StudyList.fromJson(Map<String, dynamic> json) => StudyList(
        studyUid: json["studyUID"],
        patientId: json["patientId"],
        patientName: json["patientName"],
        studyDateTime: DateTime.parse(json["studyDateTime"]),
        modalityName: json["modalityName"],
        study: json["study"],
        studyDescription: json["studyDescription"],
        refferringPhysician: json["refferringPhysician"],
        clinicalHistory: json["clinicalHistory"],
        siteName: json["siteName"],
        reportPath: json["reportPath"],
        attachmentPath: json["attachmentPath"],
        imageReceviedTime: DateTime.parse(json["imageReceviedTime"]),
        reportReceviedTime: json["reportReceviedTime"],
        noOfImages: json["noOfImages"],
        reportStatus: json["reportStatus"],
        radiologistName: json["radiologistName"],
        gender: json["gender"],
        age: json["age"],
        series: json["series"],
        siteId: json["siteID"],
        radiologistId: json["radiologistID"],
        reportReceviedTime1: json["reportReceviedTime1"] == null ? null : DateTime.parse(json["reportReceviedTime1"]),
        radiologistAssignedTime: DateTime.parse(json["radiologistAssignedTime"]),
        radcentreId: json["radcentreId"],
        examdate: DateTime.parse(json["examdate"]),
        emergencyst: json["emergencyst"],
        studycode: json["studycode"],
        repdown: json["repdown"] == null ? null : json["repdown"],
        thumbnail: json["thumbnail"],
        modality: json["modality"],
        status: json["status"],
        studyview: json["studyview"],
        studydown: json["studydown"],
    );

    Map<String, dynamic> toJson() => {
        "studyUID": studyUid,
        "patientId": patientId,
        "patientName": patientName,
        "studyDateTime": studyDateTime.toIso8601String(),
        "modalityName": modalityName,
        "study": study,
        "studyDescription": studyDescription,
        "refferringPhysician": refferringPhysician,
        "clinicalHistory": clinicalHistory,
        "siteName": siteName,
        "reportPath": reportPath,
        "attachmentPath": attachmentPath,
        "imageReceviedTime": imageReceviedTime.toIso8601String(),
        "reportReceviedTime": reportReceviedTime,
        "noOfImages": noOfImages,
        "reportStatus": reportStatus,
        "radiologistName": radiologistName,
        "gender": gender,
        "age": age,
        "series": series,
        "siteID": siteId,
        "radiologistID": radiologistId,
        "reportReceviedTime1": reportReceviedTime1 == null ? null : reportReceviedTime1.toIso8601String(),
        "radiologistAssignedTime": radiologistAssignedTime.toIso8601String(),
        "radcentreId": radcentreId,
        "examdate": examdate.toIso8601String(),
        "emergencyst": emergencyst,
        "studycode": studycode,
        "repdown": repdown == null ? null : repdown,
        "thumbnail": thumbnail,
        "modality": modality,
        "status": status,
        "studyview": studyview,
        "studydown": studydown,
    };
}

这是用于以下方面的实现:

import 'package:flutter/material.dart';
import 'package:json_parsing_example/model2.dart';

void main() => runApp(MyApp());

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

class SampleApp extends StatefulWidget {
  @override
  _SampleAppState createState() => _SampleAppState();
}

class _SampleAppState extends State<SampleApp> {
  bool _isLoading = false;
  List<StudyList> list = List();

  fetchData() async {
    setState(() {
      _isLoading = true;
    });

    String data =
        await DefaultAssetBundle.of(context).loadString("json/parse.json");

    // This is the above where you get the remote data
    // Like var response = await http.get('your url');
    //  final studyList = studyListFromJson(data);

    final studyList = studyListFromJson(data);

    list = studyList;

    setState(() {
      _isLoading = false;
    });
  }

  @override
  void initState() {
    super.initState();
    fetchData();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text('Your heading'),
        ),
        body: Container(
            child: _isLoading
                ? Center(child: CircularProgressIndicator())
                : Column(
                    children: <Widget>[
                      ListView.builder(
                        shrinkWrap: true,
                          itemCount: list.length,
                          itemBuilder: (context, index) {
                            return Card(
                              child: Column(
                                children: <Widget>[
                                  Text('${list[index].patientId }'),
                                  Text('${list[index].patientName}')
                                ],
                              ),
                            );
                          })
                    ],
                  )));
  }
}

让我知道是否有效。