List View in Flutter, that I'm trying but can't understand what is the actual error

I am new in flutter, i tried to get my data in listview. i followed this link -
https://flutter.dev/docs/cookbook/networking/fetch-data#complete-example

but don't know what is the problem. also i'am trying this way.

Eroor : Type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'List<dynamic>' in type cast

here is my full code

import 'dart:convert';
import 'dart:async';
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';

Future<List> listData() async {
  final token =
      'eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOjI4OTksImlzcyI6Imh0dHBzOi8vcG9ydGFsLWFwaS5qb21ha2hhdGEuY29tL2FwaS9hdXRoL2xvZ2luIiwiaWF0IjoxNjI5NDM2MzA1LCJleHAiOjE2Mjk1MjI3MDUsIm5iZiI6MTYyOTQzNjMwNSwianRpIjoiVWY5cEFBcVVnSG1ZdWlTMyJ9.BAjwiHMNozDWDHHrCP1p7Mt_dsNo_KNYWMQmOCuFhwQ';
  String url =
      'https://portal-api.jomakhata.com/api/getOrganizationData?token=${token}';

  Dio dio = new Dio();
  dio.options.headers['Content-Type'] = 'application/json';
  final body = {'limit': 1, 'orderBy': 'idEmployee', 'orderType': 'DESC'};
  final response = await dio.post(url, data: body);
  if (response.statusCode == 200) {
    print(response.statusCode);
    // print(response.data);
    return List.fromJson(jsonDecode(response.data));
  } else {
    throw Exception('Failed!');
  }
}

class List {
  final int idEmployee;
  final String fullName;

  List({
    required this.idEmployee,
    required this.fullName,
  });

  factory List.fromJson(Map<String, dynamic> json) {
    return List(
      idEmployee: json['idEmployee'],
      fullName: json['fullName'],
    );
  }
}

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'List View'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  late Future<List> futureAlbum;

  @override
  void initState() {
    super.initState();
    futureAlbum = listData();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: FutureBuilder<List>(
          future: futureAlbum,
          builder: (context, snapshot) {
            if (snapshot.hasData) {
              print(snapshot.data);
              return Text(snapshot.data!.fullName);
            } else if (snapshot.hasError) {
              return Text('${snapshot.error}');
            }
            return const CircularProgressIndicator();
          },
        ),
      ),
    );
  }
}

This is Error

This is json response in postman

{
    "success": true,
    "data": {
        "count": 259,
        "data": [
            {
                "idEmployee": 3559,
                "avatar": "f8b8ad832a591db9c86a157a3739d98b.jpg",
                "fullName": "A X C",
                "officeID": "1003559",
                "email": "",
                "designation": "Account Manager",
                "department": "Accounts",
                "mobileNumber": "",
                "workStation": "Software Office",
                "businessUnit": "EMD"
            }
        ],
        "query": [
            {
                "query": "select SQL_CALC_FOUND_ROWS hrEmp.employee_id AS idEmployee, `hrEmp`.`avatar` as `avatar`, `hrEmp`.`full_name` as `fullName`, `hrEmp`.`employee_custom_id` as `officeID`, `hr_organization_setup`.`off_email` as `email`, `hr_designation_master`.`designation_title` as `designation`, `hr_departments`.`department` as `department`, `hr_organization_setup`.`off_number` as `mobileNumber`, `hr_work_station`.`work_station_name` as `workStation`, `projects`.`project_name` as `businessUnit` from `hr_employee` as `hrEmp` inner join `hr_organization_setup` on `hr_organization_setup`.`employee_id` = `hrEmp`.`employee_id` inner join `projects` on `projects`.`id_projects` = `hr_organization_setup`.`id_business_unit` inner join `hr_designation_master` on `hr_designation_master`.`designation_id` = `hr_organization_setup`.`employee_desig_id` inner join `hr_departments` on `hr_departments`.`id_department` = `hr_organization_setup`.`id_department` left join `hr_work_station` on `hr_organization_setup`.`work_station_id` = `hr_work_station`.`work_station_id` where `hrEmp`.`publication_status` = ? and `hr_organization_setup`.`publication_status` = ? and `hr_organization_setup`.`working_status` in (?, ?) and `hr_designation_master`.`publication_status` = ? and `hr_departments`.`publication_status` = ? and `hr_work_station`.`publication_status` = ? order by `idEmployee` desc limit 1 offset 0",
                "bindings": [
                    "activated",
                    "activated",
                    "Working",
                    "JV",
                    "activated",
                    "activated",
                    "activated"
                ],
                "time": 7.19
            }
        ]
    },
    "id": 2899
}

i need just these data to show in listview

        "count": 259,
        "data": [
            {
                "idEmployee": 3559,
                "avatar": "f8b8ad832a591db9c86a157a3739d98b.jpg",
                "fullName": "A X C",
                "officeID": "1003559",
                "email": "",
                "designation": "Account Manager",
                "department": "Accounts",
                "mobileNumber": "",
                "workStation": "Software Office",
                "businessUnit": "EMD"
            }
        ],

And This is Android Studio Run Console

There are too many data tags here, I think that may be confusing. First, response.data is the entire response, like you posted from Postman output. Then there is a data within the response, and one more data within. This last one is an array, and you need only the first element of it.

Simply replace this line:

return List.fromJson(jsonDecode(response.data));

with this:

return List.fromJson(response.data["data"]["data"][0]);