Flutter Error: Expected a value of type ‘Map<String, dynamic>', but got one of type ‘List<dynamic>' occured

Question

I am using http: ^0.13.3, Here is my simple code and when i am running this code i got error: "Expected a value of type ‘Map<String, dynamic>', but got one of type ‘List' occured" and i don't know why i am getting this error. If there is any other way to doing that please tell me.

class SubCategoryObject {
  final int id;
  final String category;

  SubCategoryObject({@required this.id, @required this.category});

  factory SubCategoryObject.fromJson(Map<String, dynamic> json) {
    return SubCategoryObject(
      id: json['id'],
      category: json['title'],
    );
  }
}
class SubCategoryListScreen extends StatelessWidget {
  static const route = 'sub-category-list';
  SubCategoryListScreen({Key key}) : super(key: key);

  Future<SubCategoryObject> getData() async {
    final res =
        await http.get(Uri.https("jsonplaceholder.typicode.com", "todos"));

    if (res.statusCode == 200) {
      return SubCategoryObject.fromJson(jsonDecode(res.body));
    } else {
      // If that call was not successful, throw an error.
      throw Exception('Failed to load ');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("martman"),
      ),
      body: FutureBuilder<SubCategoryObject>(
        future: getData(),
        builder: (ctx, snapshot) {
          // Checking if future is resolved or not
          if (snapshot.connectionState == ConnectionState.done) {
            // If we got an error
            if (snapshot.hasError) {
              return Center(
                child: Text(
                  '${snapshot.error} occured',
                  style: TextStyle(fontSize: 18),
                ),
              );

              // if we got our data
            } else if (snapshot.hasData) {
              return Text(snapshot.data.category);
            }
          }

          // Displaying LoadingSpinner to indicate waiting state
          return Center(
            child: CircularProgressIndicator(),
          );
        },

        
      ),
    );
  }
}

print & share the screenshot of the data that you are getting from api. I believe it is a list and not a map. — Ujjwal Raijada
– Ujjwal Raijada, Commented May 6, 2021 at 18:33

MobIT · Accepted Answer · 2021-05-06 19:00:14Z

4

Please check the following link. it returns List, not Map data. https://jsonplaceholder.typicode.com/todos

Future<List<SubCategoryObject>> getData() async {
    final res =
        await http.get(Uri.https("jsonplaceholder.typicode.com", "todos"));

    if (res.statusCode == 200) {
      dynamic result = jsonDecode(res.body);
      return (result as List).map((e) => SubCategoryObject.fromJson(e)).toList();
    } else {
      // If that call was not successful, throw an error.
      throw Exception('Failed to load ');
    }
}

answered May 6, 2021 at 19:00

MobIT

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