how to handle null safety during api call flutter? - flutter

Question

am trying to do an API call where am getting an error to hangle null safety variable must be assigned.
here is my code
Future<LoginResponseModel> loginCustomer(
String username, String password) async {
LoginResponseModel model;
try {
var response = await Dio().post(Config.tokenURL,
data: {
"username": username,
"password": password,
},
options: Options(headers: {
HttpHeaders.contentTypeHeader: "application/x-www-form-urlencoded",
}));
if (response.statusCode == 200) {
model = LoginResponseModel.fromJson(response.data);
}
} on DioError catch (e) {
print(e.message);
}
return model;
}
exception am getting
The non-nullable local variable 'model' must be assigned before it can
be used. Try giving it an initializer expression, or ensure that it's
assigned on every execution path.dart
(not_assigned_potentially_non_nullable_local_variable)
is there any solution to handle this
tried "?" it's not working.
Screenshot

Answer 1

Future<LoginResponseModel?> loginCustomer(
String username, String password) async {
LoginResponseModel? model;
try {
var response = await Dio().post(Config.tokenURL,
data: {
"username": username,
"password": password,
},
options: Options(headers: {
HttpHeaders.contentTypeHeader: "application/x-www-form-urlencoded",
}));
if (response.statusCode == 200) {
model = LoginResponseModel.fromJson(response.data);
}
} on DioError catch (e) {
print(e.message);
}
return model;
}