StreamBuilder / ChangeNotifierProvider- setState() or markNeedsBuild() called during build - flutter

Question

Streambuilder, ChangeNotifier and Consumer cannot figure out how to use correctly. Flutter
I've tried and tried and tried, I've searched a lot but I cannot figure this out:
I'm using a Streambuilder this should update a ChangeNotifier that should trigger rebuild in my Consumer widget. Supposedly...
but even if I call the provider with the (listen: false) option I've got this error
The following assertion was thrown while dispatching notifications for
HealthCheckDataNotifier: setState() or markNeedsBuild() called during
build. the widget which was currently being built when the offending call was made was:
StreamBuilder<List>
Important: I cannot create the stream sooner because I need to collect other informations before reading firebase, see (userMember: userMember)
Widget build(BuildContext context) {
return MultiProvider(
providers: [
/// I have other provider...
ChangeNotifierProvider<HealthCheckDataNotifier>(create: (context) => HealthCheckDataNotifier())
],
child: MaterialApp(...
then my Change notifier look like this
class HealthCheckDataNotifier extends ChangeNotifier {
HealthCheckData healthCheckData = HealthCheckData(
nonCrewMember: false,
dateTime: DateTime.now(),
cleared: false,
);
void upDate(HealthCheckData _healthCheckData) {
healthCheckData = _healthCheckData;
notifyListeners();
}
}
then the Streambuilder
return StreamBuilder<List<HealthCheckData>>(
stream: HeathCheckService(userMember: userMember).healthCheckData,
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.active) {
if (snapshot.hasData) {
if (snapshot.data!.isNotEmpty) {
healthCheckData = snapshot.data?.first;
}
if (healthCheckData != null) {
timeDifference = healthCheckData!.dateTime.difference(DateTime.now()).inHours;
_cleared = healthCheckData!.cleared;
if (timeDifference < -12) {
healthCheckData!.cleared = false;
_cleared = false;
}
///The problem is here but don't know where to put this or how should be done
Provider.of<HealthCheckDataNotifier>(context, listen: false).upDate(healthCheckData!);
}
}
return Builder(builder: (context) {
return Provider<HealthCheckData?>.value(
value: healthCheckData,
builder: (BuildContext context, _) {
return const HealthButton();
},
);
});
} else {
return const Text('checking health'); //Scaffold(body: Loading(message: 'checking...'));
}
});
and finally the Consumer (note: the consumer is on another Route)
return Consumer<HealthCheckDataNotifier>(
builder: (context, hN, _) {
if (hN.healthCheckData.cleared) {
_cleared = true;
return Container(
color: _cleared ? Colors.green : Colors.amber[900],
Hope is enough clear,
Thank you so very much for your time!

Answer 1

it is not possible to setState(or anything that trigger rerender) in the builder callback
just like you don't setState in React render
const A =()=>{
const [state, setState] = useState([])
return (
<div>
{setState([])}
<p>will not work</p>
</div>
)
}
it will not work for obvious reason, render --> setState --> render --> setState --> (infinite loop)
so the solution is similar to how we do it in React, move them to useEffect
(example using firebase onAuthChange)
class _MyAppState extends Stateful<MyApp> {
StreamSubscription<User?>? _userStream;
var _waiting = true;
User? _user;
#override
void initState() {
super.initState();
_userStream = FirebaseAuth.instance.authStateChanges().listen((user) async {
setState(() {
_waiting = false;
_user = user;
});
}, onError: (error) {
setState(() {
_waiting = false;
});
});
}
#override
void dispose() {
super.dispose();
_userStream?.cancel();
}
#override
Widget build(context) {
return Container()
}
}