How to get value from StreamController? - flutter

Question

How to get value 'data' from StreamController
stream.listen((data) {print('$data');}) ;
// global.dart
final StreamController ctrl = StreamController();
// father.dart
onSubmitted: (value) {
debugPrint('Send Data: '+areaNameTextController.text);
ctrl.sink.add('Receive Data: '+areaNameTextController.text);},
//children.dart
GoogleMap(
...
onTap: (LatLng latlng){
ctrl.stream.listen((data) {
print('$data');} ) ;
Marker(
...
infoWindow:InfoWindow(title:'///Where I want use data///'),
);
}
)

Answer 1

You say StreamController and In your question you wroteStream.
Should fix like that.
streamController.stream.listen(
(event) => print('Event: $event'),
onDone: () => print('Done'),
onError: (error) => print(error),
);

Answer 2

In my code I use like that for pull to do pull to refresh. Listening is only purpose for listening from coming data and not for action. If you want to check something that come from BLOC controller, first listening in init state and use with action from that checked data.
void initState() {
_houseVisitBloc.listAppHouseVisitStream().listen((ResponseOb res) {
if (res.message == MsgState.data) {
List<HouseVisitAppData> listenList = res.data;
mainPullList = listenList;
print(listenList.toString());
if (mainPullList == listenList) {
_refreshController.refreshCompleted();
}
if (res.data == MsgState.data) {
_refreshController.loadComplete();
}
}
if (res.data != MsgState.data) {
_refreshController.loadNoData();
}
});
super.initState();
}

Answer 3

In my project I use a wrapper around StreamController.
It lets me to get the very last value from StreamController.
Here is the code:
class SimpleStream<T> {
final StreamController<T> _stream = StreamController<T>();
Sink<T> get _input => _stream.sink;
Stream<T> get output => _stream.stream;
T? _currentValue;
T? get current => _currentValue;
void update(T value) {
_currentValue = value;
_input.add(value);
}
void close() {
_stream.close();
}
}