How to map a json list in flutter using JSONSerializable - flutter

Question

I am trying to map a json list in my application using JSON Serializable. But I am not able to map it.
Following is the response from the API:
{
"code": 200,
"message": "Countries Lists",
"count": 250,
"data": [
{
"id": 1,
"name": "Afghanistan"
},
{
"id": 2,
"name": "Aland Islands"
},
{
"id": 3,
"name": "Albania"
},
{
"id": 4,
"name": "Algeria"
},
{
"id": 5,
"name": "American Samoa"
},
{
"id": 6,
"name": "Andorra"
},
{
"id": 7,
"name": "Angola"
},
{
"id": 8,
"name": "Anguilla"
},
{
"id": 9,
"name": "Antarctica"
},
{
"id": 10,
"name": "Antigua And Barbuda"
},
{
"id": 11,
"name": "Argentina"
},
{
"id": 12,
"name": "Armenia"
},
{
"id": 13,
"name": "Aruba"
},
{
"id": 14,
"name": "Australia"
},
{
"id": 15,
"name": "Austria"
},
{
"id": 16,
"name": "Azerbaijan"
},
{
"id": 17,
"name": "Bahamas The"
},
{
"id": 18,
"name": "Bahrain"
},
{
"id": 19,
"name": "Bangladesh"
},
{
"id": 20,
"name": "Barbados"
}
]
}
Following is my response file:
#JsonSerializable()
class BaseResponse {
#JsonKey(name: "code")
int? status;
#JsonKey(name: "message")
String? message;
}
#JsonSerializable(explicitToJson: true)
class AllCountryResponse extends BaseResponse {
#JsonKey(name: "data")
List<CountryResponse> data;
AllCountryResponse(this.data);
//from JSON
factory AllCountryResponse.fromJson(Map<String, dynamic> json) =>
_$AllCountryResponseFromJson(json);
//to JSON
Map<String, dynamic> toJson() => _$AllCountryResponseToJson(this);
}
#JsonSerializable()
class CountryResponse {
#JsonKey(name: "id")
String? id;
#JsonKey(name: "name")
String? name;
CountryResponse(this.id, this.name);
//from JSON
factory CountryResponse.fromJson(Map<String, dynamic> json) =>
_$CountryResponseFromJson(json);
//to JSON
Map<String, dynamic> toJson() => _$CountryResponseToJson(this);
}
I am able to generate the responses.g dart file.
Following is my mapper class file:
class Countries {
String id,name;
Countries(this.id,this.name);
}
class AllCountries{
List<Countries> countries;
AllCountries(this.countries);
}
extension CountryResponseMapper on CountryResponse? {
Countries toDomain() {
return Countries(
this?.id.orEmpty() ?? EMPTY, this?.name.orEmpty() ?? EMPTY);
}
}
extension AllCountriesResponseMapper on AllCountryResponse? {
AllCountries toDomain() {
return AllCountries(this?.data.map((e) => e.toDomain()).toList() ?? []);
}
}
Once I run my api I do get 200 status while using my bio, but after that it shows me the default error I have set, i.e. "Something went wrong". Which means there is an issue in mapping the response.
Can someone help me with mapping this list please?

Answer 1

This code should work.
This code is generated by a very small and simple script (which was written in a few minutes).
class Response {
Response(
{required this.code,
required this.message,
required this.count,
required this.data});
factory Response.fromJson(Map json) {
return Response(
code: json['code'] as int?,
message: json['message'] as String?,
count: json['count'] as int?,
data: json['data'] == null
? []
: (json['data'] as List).map((e) => Data.fromJson(e as Map)).toList(),
);
}
final int? code;
final String? message;
final int? count;
final List<Data> data;
static List<Response> fromJsonList(List json) {
return json.map((e) => Response.fromJson(e as Map)).toList();
}
Map<String, dynamic> toJson() {
return {
'code': code,
'message': message,
'count': count,
'data': data.map((e) => e.toJson()).toList(),
};
}
static List<Map<String, dynamic>> toJsonList(List<Response> list) {
return list.map((e) => e.toJson()).toList();
}
}
class Data {
Data({required this.id, required this.name});
factory Data.fromJson(Map json) {
return Data(
id: json['id'] == null ? 0 : json['id'] as int,
name: json['name'] == null ? '' : json['name'] as String,
);
}
final int id;
final String name;
static List<Data> fromJsonList(List json) {
return json.map((e) => Data.fromJson(e as Map)).toList();
}
Map<String, dynamic> toJson() {
return {
'id': id,
'name': name,
};
}
static List<Map<String, dynamic>> toJsonList(List<Data> list) {
return list.map((e) => e.toJson()).toList();
}
}
Code generation script:
import 'dart:io';
import 'package:object_serializer/json_serializer_generator.dart';
import 'package:yaml/yaml.dart';
void main() {
final classes = loadYaml(_classes) as Map;
final g = JsonSerializerGenerator();
final classesCode = g.generateClasses(classes);
final values = {
'classes': classesCode,
};
var source = g.render(_template, values);
source = g.format(source);
File('bin/stackoverflow.dart').writeAsStringSync(source);
}
const _classes = r'''
Response:
fields:
code: int?
message: String?
count: int?
data: List<Data>
Data:
fields:
id: int
name: String
''';
const _template = r'''
{{classes}}
''';