Unhandled Exception: A class was used after being disposed. - Flutter - flutter

Question

I'm getting this error
E/flutter ( 9610): [ERROR:flutter/lib/ui/ui_dart_state.cc(166)] Unhandled Exception: A CustRegViewModel was used after being disposed.
E/flutter ( 9610): Once you have called dispose() on a CustRegViewModel, it can no longer be used.
I have a View named CustRegView where I take a phone number form the user and send it to ViewModel named CustRegViewModel to authenticate which returns bool based on its authentication status.
class CustRegView extends StatefulWidget {
#override
_CustRegViewState createState() => _CustRegViewState();
}
class CustRegView extends StatelessWidget{
final TextEditingController _controller = TextEditingController();
#override
Widget build(BuildContext context) {
final deviceSize = MediaQuery.of(context).size;
return BaseView<CustRegViewModel>(
builder: (context, model, child) => Scaffold(
...<some code>
FlatButton (
onPressed: () async {
var registerSuccess = await model.register( _controller.text, context);
// ^^^^^ HERE, IN ABOVE LINE, I'M GETTING AN ERROR ^^^^^^
if (registerSuccess) {
Navigator.pushNamed(context, 'newScreen');
} else {
UIHelper().showErrorButtomSheet(context, model.errorMessage);
}
)
}
CustRegViewModel looks like this
class CustRegViewModel extends BaseViewModel {
final AuthService _authService = locator<AuthService>();
final DialogService _dialogService = locator<DialogService>();
dynamic newUserResult;
dynamic verifyResult;
Future<bool> register(String phoneNo, BuildContext context) async {
await verifyPhone;
return verifyResult ? true : false; // From here it returns true
}
Future<void> verifyPhone(phoneNo) async {
await FirebaseAuth.instance.verifyPhoneNumber(
phoneNumber: updatedPhoneNo,
timeout: Duration(seconds: 50),
verificationCompleted: (AuthCredential authCred) async {...... <some code>
verificationFailed: (AuthException authException) {...... <some code>
codeSent: (String verID, [int forceCodeResend]) async {...... <some code>
codeAutoRetrievalTimeout: (String verID) {...
).catchError((error) {...... <some code>
}
}
BaseView looks like this
class BaseView<T extends BaseViewModel> extends StatefulWidget {
final Widget Function(BuildContext context, T model, Widget child) builder;
final Function(T) onModelReady;
BaseView({this.builder, this.onModelReady});
#override
_BaseViewState<T> createState() => _BaseViewState<T>();
}
class _BaseViewState<T extends BaseViewModel> extends State<BaseView<T>> {
T model = locator<T>();
#override
void initState() {
if (widget.onModelReady != null) {
widget.onModelReady(model);
}
super.initState();
}
#override
Widget build(BuildContext context) {
return ChangeNotifierProvider<T>(
create: (context) => model,
child: Consumer<T>(builder: widget.builder),
);
}
}
BaseViewModel looks like this
class BaseViewModel extends ChangeNotifier {
ViewState _state = ViewState.Idle;
ViewState get state => _state;
void setState(ViewState viewState) {
_state = viewState;
notifyListeners();
}
}

Answer 1

You may have used RegisterLazySingleton instead of Factory in your depencie injection.