The getter 'data' was called on null in response - flutter

Question

I expext response.data to be when i got an error 422, like
{
"message": "You can NOT add a penalty!"
}
but i have an error The getter 'data' was called on null.
Future transferCoinsToUser(
String apiToken, String recipientBill, int coin) async {
Response response;
try {
response = await _dio.post(apiEndpoint + "bills/transfer",
options: Options(headers: {"Authorization": apiToken}),
data: {"recipient_bill": recipientBill, "coin": coin});
if(response.statusCode == 200){
print('status cod ' + response.statusCode.toString());
print('response bady ' + response.data.toString());//{message: completed successfully.}
}
} on DioError catch (error) {
print(error);
print(response.data);// The getter 'data' was called on null.
return null;
}
}
my stack trace
NoSuchMethodError: The getter 'data' was called on null.
I/flutter ( 7462): Receiver: null
I/flutter ( 7462): Tried calling: data
I/flutter ( 7462): NoSuchMethodError: The getter 'data' was called on null.
I/flutter ( 7462): Receiver: null
I/flutter ( 7462): Tried calling: data
I/flutter ( 7462): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
I/flutter ( 7462): #1 ApiProvider.transCoinToUser (package:no_fine/data/api_provider.dart:104:22)
I/flutter ( 7462): <asynchronous suspension>
I/flutter ( 7462): #2 TransferRepositoryImpl.transCoinToUser (package:no_fine/data/repository/transfer_repo.dart:37:20)
I/flutter ( 7462): <asynchronous suspension>
I/flutter ( 7462): #3 TransferBloc._mapTransferCoinsToUserToState (package:no_fine/bloc/auth/translations_bloc/translations_bloc.dart:42:33)
I/flutter ( 7462): <asynchronous suspension>
I/flutter ( 7462): #4 TransferBloc.mapEventToState (package:no_fine/bloc/auth/translations_bloc/translations_bloc.dart:26:14)
I/flutter ( 7462): <asynchronous suspension>
I/flutter ( 7462): #5 Bloc._bindEventsToStates.<anonymous closure> (package:bloc/src/bloc.dart:232:20)
I/flutter ( 7462): #6 Stream.asyncExpand.<anonymous closure>.<anonymous closure> (dart:async/stream.dart:644:30)
I/flutter ( 7462): #7 _rootRunUnary (dart:async/zone.dart:1198:47)
I/flutter ( 7462): #8 _CustomZone.runUnary (dart:async/zone.dart:1100:19)
I/flutter ( 7462): #9 _CustomZone.runUnaryGuarded (dart:async/zone.dart:1005:7)
I/flutter ( 7462): #10 _BufferingStreamSubscription._sendData (dart:a

Answer 1

response might be null. You are calling .data on null hence the error. Try
print(response?.data)
or check
if(response != null) print(response.data);

Answer 2

You can't access the Response object, when you have an error. Instead, Please use below code:
on DioError catch (error) {
print(error);
print(error.response.data);// Here you will find the error response in error object
return null;
}

Answer 3

You can check your request host. In Android device you can not use the request host like "localhost" or "127.0.0.1" directly because this is the Android device's host and this is not your API host.You should use your API host's IP which like "http://192.168.50.123/request?foo=bar".