Bloc: Unhandled Exception BlocProvider.of()
Hi ,
Get this erreur :
[ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: BlocProvider.of() called with a context that does not contain a Bloc of type AuthenticationBloc. E/flutter (12064): No ancestor could be found starting from the context that was passed to BlocProvider.of
I try to create a little application based in yours flutter_firebase_login.
This error is produced after succesfuil login and switch to AuthenticationAuthenticated state.
when I make reload with rebuild MAJ + R the error go way and I can switch to HomePage
my configuration
cupertino_icons: ^0.1.2
bloc: ^2.0.0
flutter_bloc: ^2.1.1
meta: ^1.1.6
equatable: ^1.0.0
Thank for you help
my main.dart
`void main() {
WidgetsFlutterBinding.ensureInitialized();
BlocSupervisor.delegate = SimpleBlocDelegate();
final UserRepository userRepository = UserRepository();
runApp(
BlocProvider
create: (context) => AuthenticationBloc(
userRepository: userRepository,
)..add(AppStarted()),
child: App(userRepository: userRepository),
),
);
}
class App extends StatelessWidget {
final UserRepository _userRepository;
final ThemeData _theme = Themes.light;
App({Key key, @required UserRepository userRepository})
: assert(userRepository != null),
_userRepository = userRepository,
super(key: key);
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'S1',
theme: _theme,
home: BlocBuilder
builder: (context, state) {
BlocProvider.of
if (state is AuthenticationUnauthenticated) {
return LoginPage(userRepository: _userRepository);
}
if (state is AuthenticationAuthenticated) {
return HomePage(name: "Test");
}
if (state is AuthenticationLoading) {
return LoadingIndicator();
}
return SplashPage();
},
),
);
}
}`
vassilux
All 12 comments
Hi @vassilux 👋
Thanks for opening an issue!
Are you able to share a link to the full source code? Thanks!
felangel
on 26 Dec 2019
thank for you response
this is a link to repo https://github.com/vassilux/fsone/tree/master/lib
vassilux
on 26 Dec 2019
No problem! I took a quick look and don't understand why you need this line https://github.com/vassilux/fsone/blob/fefc5da5cccbc6ec1283c4927fd85432746cf73a/lib/main.dart#L54. You can't access the bloc from the same context in which it was provided.
felangel
on 26 Dec 2019
yes it was I just stupid teste I forgot to delete
vassilux
on 26 Dec 2019
Felix,
my problem is in login_form.dart
if (state.isSuccess) {
BlocProvider.of<AuthenticationBloc>(context)
.add(LoggedIn());
}
there is a chance that I don't understand well something with flutter_bloc library , so LoginPage does not contain a AuthentificaitonBloc
I found some examples on the `https://www.didierboelens.com/fr/2018/12/reactive-programming---streams---bloc---cas-practiques-dutilisation/
void main() => runApp(Application());
class Application extends StatelessWidget {
@override
Widget build(BuildContext context) {
return BlocProvider
bloc: AuthenticationBloc(),
child: MaterialApp(
title: 'BLoC Samples',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: InitializationPage(),
),
);
}
}`
Other thing I can not see the property bloc of BlocProvider
vassilux
on 26 Dec 2019
Hi @vassilux I took a look at https://github.com/vassilux/fsone/tree/master and you are missing required files such as a pubspec.yaml so I am unable to run the project locally. Can you please update the project so that it can be run locally? Thanks!
felangel
on 27 Dec 2019
yes done
vassilux
on 27 Dec 2019
@vassilux I ran it locally and had no issues. My login_form.dart looks like:
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:fsone/blocs/authentication/bloc.dart';
import 'package:fsone/blocs/login/bloc.dart';
import 'package:fsone/config/assets.dart';
import 'package:fsone/widgets/headers/wavy_header.dart';
import 'login_button.dart';
class LoginForm extends StatefulWidget {
@override
State<LoginForm> createState() => _LoginFormState();
}
class _LoginFormState extends State<LoginForm> {
final _usernameController = TextEditingController();
final _passwordController = TextEditingController();
//LoginBloc _loginBloc;
bool get isPopulated =>
_usernameController.text.isNotEmpty &&
_passwordController.text.isNotEmpty;
bool isLoginButtonEnabled(LoginState state) {
return state.isFormValid && isPopulated && !state.isSubmitting;
}
@override
void initState() {
super.initState();
_usernameController.addListener(_onEmailChanged);
_passwordController.addListener(_onPasswordChanged);
}
void _onEmailChanged() {
BlocProvider.of<LoginBloc>(context).add(
UserNameChanged(username: _usernameController.text),
);
}
void _onPasswordChanged() {
BlocProvider.of<LoginBloc>(context).add(
PasswordChanged(password: _passwordController.text),
);
}
@override
Widget build(BuildContext context) {
void _onFormSubmitted() {
BlocProvider.of<LoginBloc>(context).add(
LoginButtonPressed(
username: _usernameController.text,
password: _passwordController.text,
),
);
}
return BlocListener<LoginBloc, LoginState>(
listener: (context, state) {
if (state.isFailure) {
Scaffold.of(context)
..hideCurrentSnackBar()
..showSnackBar(
SnackBar(
content: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [Text('Login Failure'), Icon(Icons.error)],
),
backgroundColor: Colors.red,
),
);
}
if (state.isSubmitting) {
Scaffold.of(context)
..hideCurrentSnackBar()
..showSnackBar(
SnackBar(
content: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Text('Logging In...'),
CircularProgressIndicator(),
],
),
),
);
}
if (state.isSuccess) {
BlocProvider.of<AuthenticationBloc>(context).add(
LoggedIn(token: 'token'),
);
}
},
child: BlocBuilder<LoginBloc, LoginState>(
builder: (context, state) {
return Padding(
padding: EdgeInsets.all(0.2),
child: Form(
child: ListView(
children: <Widget>[
buildHeaderSectionWidget(),
/*Padding(
padding: EdgeInsets.symmetric(vertical: 20),
child: Image.asset('assets/flutter_logo.png', height: 50),
),*/
Container(
decoration: BoxDecoration(
border: Border.all(
color: Colors.grey.withOpacity(0.5),
width: 1.0,
),
borderRadius: BorderRadius.circular(20.0),
),
margin: const EdgeInsets.symmetric(
vertical: 10.0, horizontal: 20.0),
child: Row(
children: <Widget>[
new Padding(
padding: EdgeInsets.symmetric(
vertical: 10.0, horizontal: 15.0),
child: Icon(
Icons.person_outline,
color: Colors.grey,
),
),
Container(
height: 30.0,
width: 1.0,
color: Colors.grey.withOpacity(0.5),
margin:
const EdgeInsets.only(left: 00.0, right: 10.0),
),
new Expanded(
child: TextFormField(
controller: _usernameController,
decoration: InputDecoration(
border: InputBorder.none,
hintText: 'Enter your username',
hintStyle: TextStyle(color: Colors.grey),
),
keyboardType: TextInputType.text,
autovalidate: true,
autocorrect: false,
validator: (_) {
return !state.isUsernameValid
? 'Invalid Username'
: null;
}),
)
],
),
),
//fin
Container(
decoration: BoxDecoration(
border: Border.all(
color: Colors.grey.withOpacity(0.5),
width: 1.0,
),
borderRadius: BorderRadius.circular(20.0),
),
margin: const EdgeInsets.symmetric(
vertical: 10.0, horizontal: 20.0),
child: Row(
children: <Widget>[
new Padding(
padding: EdgeInsets.symmetric(
vertical: 10.0, horizontal: 15.0),
child: Icon(
Icons.lock_open,
color: Colors.grey,
),
),
Container(
height: 30.0,
width: 1.0,
color: Colors.grey.withOpacity(0.5),
margin:
const EdgeInsets.only(left: 00.0, right: 10.0),
),
new Expanded(
child: TextFormField(
controller: _passwordController,
decoration: InputDecoration(
border: InputBorder.none,
hintText: 'Enter your password',
hintStyle: TextStyle(color: Colors.grey),
),
obscureText: true,
autovalidate: true,
autocorrect: false,
validator: (_) {
return !state.isPasswordValid
? 'Invalid Password'
: null;
},
),
)
],
),
),
// end new passwpord
Padding(
padding: EdgeInsets.symmetric(vertical: 20),
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
LoginButton(
onPressed: isLoginButtonEnabled(state)
? _onFormSubmitted
: null,
),
//GoogleLoginButton(),
//CreateAccountButton(userRepository: _userRepository),
],
),
),
],
),
),
);
},
),
);
}
buildHeaderSectionWidget() {
return Column(children: <Widget>[
WavyHeader(),
// Container(
// margin: EdgeInsets.only(top: 10),
// child: Image.asset(Assets.app_icon, height: 100)),
Container(
margin: EdgeInsets.only(top: 10),
child: Text('S1',
style: TextStyle(
// color: Colors.white,
fontWeight: FontWeight.bold,
fontSize: 22)))
]);
}
@override
void dispose() {
_usernameController.dispose();
_passwordController.dispose();
super.dispose();
}
}
Closing for now since it seems like everything is working as expected. Feel free to comment with additional information/questions and I'm happy to continue the conversation 👍
felangel
on 27 Dec 2019
Ok Felix,
It is interesting point to understand where is problem , maybe this behavior is caused by environment
Application was tested on debug mode debug on device and Emulator
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel master, v1.13.6-pre.16, on Microsoft Windows [version 10.0.18362.207], locale fr-FR)
[√] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
[√] Android Studio (version 3.5)
[√] VS Code, 64-bit edition (version 1.38.1)
[√] Connected device (1 available)
• No issues found!
vassilux
on 28 Dec 2019
@vassilux do you have any problems running the default login example?
felangel
on 30 Dec 2019
Yes Felix it works good I just added
android.useAndroidX=true
android.enableJetifier=true
and changed compileSdkVersion 28
I will continue to look for solution and copare with your example
vassilux
on 30 Dec 2019
Felix,
so I used your default login example as base of my project and now it is work , my code was imported into your project
Thank for your help and happy new year
vassilux
on 31 Dec 2019
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Most helpful comment
Felix,
so I used your default login example as base of my project and now it is work , my code was imported into your project
Thank for your help and happy new year