flutter : type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'List<dynamic>'

everyone. I am new to flutter. I am making an UI where I want to display the data with the help of the api but get stuck on the following error…

This is the screenshot of the error display on UI

I don’t know why it is displaying. Please guide me what I’m doing wrong here so that I could fix it.

Thanks for the help.

Below is the code where i want to display the text on the UI

import 'package:flutter/material.dart';
import 'package:shubh_chintak/ShubhChintak/constants.dart';
import 'package:shubh_chintak/ShubhChintak/reusableWidget.dart';
import 'package:shubh_chintak/ShubhChintakGetAPI/ShubhChintakHttp/FarmerPreHarvestingGetHttp.dart';
import 'package:shubh_chintak/ShubhChintakGetAPI/ShubhChintakModelClasses/ShubhChintakModel.dart';

import 'farmerPostHarvestingCropDescription/farmerPostHarvestingCropDescription.dart';

class FarmerPostHarvesting extends StatefulWidget {
  const FarmerPostHarvesting({Key? key}) : super(key: key);

  @override
  State<FarmerPostHarvesting> createState() => _FarmerPostHarvestingState();
}

class _FarmerPostHarvestingState extends State<FarmerPostHarvesting> {
  final FarmerPreHarvestingGetHttp _farmerPreHarvestingGetHttp =
      FarmerPreHarvestingGetHttp();

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: FutureBuilder<List<FarmerPreHarvestingModel>>(
        future: _farmerPreHarvestingGetHttp.getPreHarvestingData(),
        builder: (context, snapshot) {
          if (snapshot.hasData) {
            List<FarmerPreHarvestingModel> preHarvestingData = snapshot.data!;
            return showPreHarvestingData(context, preHarvestingData);
          } else if (snapshot.hasError) {
            return Center(
              child: Text(
                snapshot.error.toString(),
              ),
            );
          } else {
            return const Center(
              child: CircularProgressIndicator(),
            );
          }
        },
      ),
    );
  }
}

ListView showPreHarvestingData(
    BuildContext context, List<FarmerPreHarvestingModel> preHarvestingData) {
  return ListView.builder(
    itemCount: preHarvestingData.length,
    itemBuilder: (context, index) {
      return SizedBox(
        height: MediaQuery.of(context).size.height * 0.13,
        child: Card(
          shadowColor: kPrimaryColor,
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(20),
            side: const BorderSide(color: kPrimaryColor),
          ),
          elevation: 5,
          semanticContainer: true,          
          child: ListTile(
            onTap: () {
              Navigator.push(
                context,
                MaterialPageRoute(
                  builder: (context) =>
                      const FarmerPostHarvestingCropDescription(),
                ),
              );
            },
            title: reusableText(
                "${preHarvestingData[index].cropName}", 20, TextAlign.start),
            subtitle: reusableText(
                "${preHarvestingData[index].cropArea}", 15, TextAlign.start),
            trailing: reusableText(
                "${preHarvestingData[index].cropInitialCosting}",
                20,
                TextAlign.end),
          ),
        ),
      );
    },
  );
}

Here is the FarmerPreHarvestingGetHttp.dart file code for the API

import 'dart:convert';

import 'package:http/http.dart';
import 'package:shubh_chintak/ShubhChintakGetAPI/ShubhChintakModelClasses/ShubhChintakModel.dart';

class FarmerPreHarvestingGetHttp {
  final String baseUrl =
      "http://shubhchintak.digicommunique.com/Registration.asmx/ShowGetData";

  Future<List<FarmerPreHarvestingModel>> getPreHarvestingData() async {
    Response res = await get(Uri.parse(baseUrl));
    if (res.statusCode == 200) {
      List<dynamic> data = jsonDecode(res.body);
      List<FarmerPreHarvestingModel> preHarvestingData = data
          .map((dynamic item) => FarmerPreHarvestingModel.fromJson(item))
          .toList();
      return preHarvestingData;
    } else {
      throw "Something went wrong";
    }
  }
}

Here is the Model class of the API i.e., ShubhChintakModel.dart file.

class FarmerPreHarvestingModel {
  int? cropId;
  String? cropName;
  String? cropArea;
  String? cropInitialCosting;

  FarmerPreHarvestingModel({
    this.cropId,
    this.cropName,
    this.cropArea,
    this.cropInitialCosting,
  });

  FarmerPreHarvestingModel.fromJson(Map<String, dynamic> json) {
    cropId = json['crop_id'];
    cropName = json['crop_name'];
    cropArea = json['crop_area'];
    cropInitialCosting = json['crop_initialCosting'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['crop_id'] = this.cropId;
    data['crop_name'] = this.cropName;
    data['crop_area'] = this.cropArea;
    data['crop_initialCosting'] = this.cropInitialCosting;
    return data;
  }
}

This is what i had try so far, but did not able to solve the error.

>Solution :

your response are a map, and the data that you need is a list with key data

your response:

{
  "result": "Success",
  "message": "Show All Data",
  "data": [
    {
      "crop_id": 46,
      "crop_name": "Rice",
      "crop_area": "343",
      "crop_initialCosting": "10000"
    }
  ]
}

you need to get the data and serialize to your model

Workaround:

Future<List<FarmerPreHarvestingModel>> getPreHarvestingData() async {
    Response res = await get(Uri.parse(baseUrl));
    if (res.statusCode == 200) {
/// update here >>>>>>>
      final resp = jsonDecode(res.body); // this is Map
      List<dynamic> data = resp["data"]; // this is List
      List<FarmerPreHarvestingModel> preHarvestingData = data
          .map((dynamic item) => FarmerPreHarvestingModel.fromJson(item))
          .toList();
      return preHarvestingData;
    } else {
      throw "Something went wrong";
    }
  }