How to solve the problem with types in flutter? - flutter

Question

I have an array of elements that come from api and I get and error from api =>
The operator '[]' isn't defined for the type of 'Country'
Response from api looks like this:
{"success":true,"list":[{"id":2,"createdAt":"2022-11-11T15:25:31.680Z","updatedAt":"2022-11-11T15:25:31.680Z","name":"Afghanistan"}]}
This is the type of an element inside list:
class Country {
final int id;
final String createdAt;
final String updatedAt;
final String name;
const Country({
required this.id,
required this.createdAt,
required this.updatedAt,
required this.name
});
}
This is my widget:
class MyWidget extends StatefulWidget {
const MyWidget({super.key});
#override
State<MyWidget> createState() => _MyWidgetState();
}
class _MyWidgetState extends State<MyWidget> {
List<Country> countries = [];
Future<void> getCountries() async {
try {
final response = await _apiService.getCountries();
countries = response['list']; // [{"id": 2, "createdAt:""...}]
} catch (e) {
log(e.toString());
rethrow;
}
}
#override
void initState() {
getCountries();
super.initState();
}
#override
Widget build(BuildContext context) {
return Container();
}
}
And if I try to call this, IDE lights me this error in country['name'] =>
final List countriesWithNames = countries.map((country) => country['name']).toList();
Or when I try to get an element from the list, like this => countries[index]['name']

Answer 1

response['list'] returns list of map.You need to convert into model class.
You can use this model class
class Country {
final int id;
final String createdAt;
final String updatedAt;
final String name;
const Country({
required this.id,
required this.createdAt,
required this.updatedAt,
required this.name,
});
Map<String, dynamic> toMap() {
final result = <String, dynamic>{};
result.addAll({'id': id});
result.addAll({'createdAt': createdAt});
result.addAll({'updatedAt': updatedAt});
result.addAll({'name': name});
return result;
}
factory Country.fromMap(Map<String, dynamic> map) {
return Country(
id: map['id']?.toInt() ?? 0,
createdAt: map['createdAt'] ?? '',
updatedAt: map['updatedAt'] ?? '',
name: map['name'] ?? '',
);
}
String toJson() => json.encode(toMap());
factory Country.fromJson(String source) =>
Country.fromMap(json.decode(source));
}
And getting from local json string
final data = response["list"] as List?;
List<Country> countries =
data?.map((e) => Country.fromMap(e)).toList() ?? [];
print(countries);