type is not subtype of type Map<String, dynamic>' in flutter

Question

I have a data that I pulled from json. I want to receive and process this data in the following format. When I try manually, I get the error with the actual service data while getting the output I want. My manual attempt:

void main(List<String> args) {
  final map = <Map<String, dynamic>>[
    {'MAH_ID': 10, 'MAH_AD': 'AŞAĞI', 'ILCE_ID': 1, 'ILCE_AD': 'SARI'},
    {'MAH_ID': 11, 'MAH_AD': 'YUKARI', 'ILCE_ID': 1, 'ILCE_AD': 'SARI'},
    {'MAH_ID': 12, 'MAH_AD': 'SAĞ', 'ILCE_ID': 1, 'ILCE_AD': 'SARI'},
    {'MAH_ID': 13, 'MAH_AD': 'SOL', 'ILCE_ID': 1, 'ILCE_AD': 'SARI'},
    {'MAH_ID': 14, 'MAH_AD': 'LOW', 'ILCE_ID': 2, 'ILCE_AD': 'KIRMIZI'},
    {'MAH_ID': 15, 'MAH_AD': 'MİD', 'ILCE_ID': 2, 'ILCE_AD': 'KIRMIZI'},
    {'MAH_ID': 16, 'MAH_AD': 'HİGH', 'ILCE_ID': 2, 'ILCE_AD': 'KIRMIZI'},
    {'MAH_ID': 17, 'MAH_AD': 'ULTRAHİGH', 'ILCE_ID': 2, 'ILCE_AD': 'KIRMIZI'}
  ];

  final mappedValues = <Map<String, List<dynamic>>>[];

  for (final element in map) {
    final ilceAd = element['ILCE_AD'];
    final mahAd = element['MAH_AD'];

    final contains =
        mappedValues.where((e) => e.keys.contains(ilceAd)).toList();

    if (contains.isNotEmpty) {
      if (contains.first.isNotEmpty) {
        if (contains.first.containsKey(ilceAd)) {
          contains.first[ilceAd]!.add(mahAd);
        }
      }
    } else {
      mappedValues.add({
        ilceAd as String: [mahAd]
      });
    }
  }

  print(mappedValues);
}

success output {SARI: [AŞAĞI, YUKARI, SAĞ, SOL]}, {KIRMIZI: [LOW, MİD, HİGH, ULTRAHİGH]}]

my model class

import 'dart:convert';

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

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

class Mahalle {
  Mahalle({
    this.mahId,
    this.mahAdi,
    this.mahIdDbb,
    this.ilceId,
    this.ilceAdi,
    this.ilceIdDbb,
  });

  int? mahId;
  String? mahAdi;
  int? mahIdDbb;
  int? ilceId;
  String? ilceAdi;
  int? ilceIdDbb;

  factory Mahalle.fromJson(Map<String, dynamic> json) => Mahalle(
        mahId: json["MAH_ID"],
        mahAdi: json["MAH_ADI"],
        mahIdDbb: json["MAH_ID_DBB"],
        ilceId: json["ILCE_ID"],
        ilceAdi: json["ILCE_ADI"],
        ilceIdDbb: json["ILCE_ID_DBB"],
      );

  Map<String, dynamic> toJson() => {
        "MAH_ID": mahId,
        "MAH_ADI": mahAdi,
        "MAH_ID_DBB": mahIdDbb,
        "ILCE_ID": ilceId,
        "ILCE_ADI": ilceAdi,
        "ILCE_ID_DBB": ilceIdDbb,
      };
}

method where i pull json data

Future getApiData() async {
    try {
      final response = await http.get(url);
      if (response.statusCode == 200) {
        var result =
            mahalleFromJson(response.body).cast<Map<String, dynamic>>();

        final mappedValues = <Map<String, List<dynamic>>>[];

        for (final element in result) {
          final ilceAd = element['ilceAdi'];
          final mahAd = element["mahAdi"];

          final contains = mappedValues
              .where((element) => element.keys.contains(ilceAd))
              .toList();

          if (contains.isNotEmpty) {
            if (contains.first.isNotEmpty) {
              if (contains.first.containsKey(ilceAd)) {
                contains.first[ilceAd]!.add(mahAd);
              }
            }
          } else {
            mappedValues.add({
              ilceAd as String: [mahAd]
            });
          }
        }
        print(mappedValues);
}

the error i got: type 'Mahalle' is not a subtype of type 'Map<String, dynamic>' in type cast

Thanks in advance for your help

eamirho3ein · Accepted Answer · 2022-10-12 08:04:50Z

1

element in your for loop is an Mahalle Item, so if you want to access ilceAd or mahAd you should do this:

var result = mahalleFromJson(response.body); //<--- change this

final mappedValues = <Map<String, List<dynamic>>>[];

for (final element in result) {
          final ilceAd = element.ilceAdi; //<--- change this
          final mahAd = element.mahAdi; //<--- change this

          final contains = mappedValues
              .where((element) => element.keys.contains(ilceAd))
              .toList();

          if (contains.isNotEmpty) {
            if (contains.first.isNotEmpty) {
              if (contains.first.containsKey(ilceAd)) {
                contains.first[ilceAd]!.add(mahAd);
              }
            }
          } else {
            mappedValues.add({
              ilceAd as String: [mahAd]
            });
          }
        }

edited Oct 12, 2022 at 8:04

answered Oct 12, 2022 at 7:46

eamirho3ein

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3 Comments

Uğur DANA Over a year ago

I can't get such access. Because the result is List<Map> while the element is just Map

Uğur DANA Over a year ago

I finally got it done mate. There was no need for the cast process above, it was solved by the method you said when you deleted it. Thank you so much.

eamirho3ein Over a year ago

glad to hear that. appreciate it if you up vote me.

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