Flutter Json Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Iterable<dynamic>'

Question

Class Category Error: Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Iterable'

  class Category {
  int id;
  String categoryName;
  String seoUrl;


  Category(this.id,this.categoryName,this.seoUrl);

  Category.fromJson(Map json){
    id = json["id"];
    categoryName = json["categoryName"];
    seoUrl = json["seoUrl"];
  }

  Map toJson(){
    return {
      "id": id,
      "categoryName": categoryName,
      "seoUrl": seoUrl
    };
  }
}

Class Main Screen

Error: Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Iterable'


import 'dart:convert';

import 'package:flutter/material.dart';
import 'package:http_demo/data/api/category_api.dart';
import 'package:http_demo/models/category.dart';

class MainScreen extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return MainScreenState();
  }
}

class MainScreenState extends State {
  List<Category> categories = List<Category>();
  List<Widget> categoryWidgets = List<Widget>();

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
          "Alışveriş Sistemi",
          style: TextStyle(color: Colors.white),
        ),
        backgroundColor: Colors.blueGrey,
        centerTitle: true,
      ),
      body: Padding(
        padding: EdgeInsets.all(10.0),
        child: Column(
          children: <Widget>[
            SingleChildScrollView(
              scrollDirection: Axis.horizontal,
              child: Row(
                children: categoryWidgets,
              ),
            )
          ],
        ),
      ),
    );
  }

  void getCategoriesFromApi() {
    CategoryApi.getCategories().then((response) {
      setState(() {
        Iterable list = json.decode(response.body);
        //categories = list.map((category) => Category.fromJson(category)).toList();
        this.categories = List<Category>.from(list.map((model)=> Category.fromJson(model)));
        getCategoryWidgets();
      });
    });
  }

  List<Widget> getCategoryWidgets() {
    for (int i = 0; i < categories.length; i++) {
      categoryWidgets.add(getCategoryWidget(categories[i]));
    }
    return categoryWidgets;
  }

  Widget getCategoryWidget(Category category) {
    return FlatButton(
      onPressed: null,
      child: Text(
        category.categoryName,
        style: TextStyle(color: Colors.blueGrey),
      ),
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(15.0),
        side: BorderSide(color: Colors.lightGreenAccent),
      ),
    );
  }
}

Error: Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Iterable<dynamic>' Error: Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Iterable' Error: Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Iterable' Error: Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Iterable' Error: Unhandled Exception: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Iterable'

MobIT · Accepted Answer · 2021-05-11 00:39:27Z

1

Please check the response after convert JSON.

void getCategoriesFromApi() {
  CategoryApi.getCategories().then((response) {
    setState(() {
      var list = json.decode(response.body);
      //categories = list.map((category) => Category.fromJson(category)).toList();
      if (list is List) {
        this.categories = list.map((e) => Category.fromJson(e)).toList();
        getCategoryWidgets();
      } else {
        print('response is not list');
      }
    });
  });
}

edited May 11, 2021 at 0:39

answered May 10, 2021 at 22:15

MobIT

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9 Comments

MobIT Over a year ago

can you share the response.body ?

umutcan bağdu Over a year ago

I got the text "response is not list" import 'package:http/http.dart' as http; class CategoryApi{ static Future getCategories(){ return http.get("10.0.2.2:3000/category"); } }

MobIT Over a year ago

Yes. you can check the response. print(response.body);

umutcan bağdu Over a year ago

class Category { int id; String categoryName; String seoUrl; Category(this.id,this.categoryName,this.seoUrl); Category.fromJson(Map json){ id = json["id"]; categoryName = json["categoryName"]; seoUrl = json["seoUrl"]; } Map toJson(){ return { "id": id, "categoryName": categoryName, "seoUrl": seoUrl }; } }

umutcan bağdu Over a year ago

I'm using bluestack.

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