Flutter : Bad state: Stream has already been listened to

Question

     class MyPage extends StatelessWidget {       @override       Widget build(BuildContext context) {         return DefaultTabController(           length: 2,           child: new Scaffold(             appBar: TabBar(               tabs: [                 Tab(child: Text("MY INFORMATION",style: TextStyle(color: Colors.black54),)),                 Tab(child: Text("WEB CALENDER",style: TextStyle(color: Colors.black54),)),               ],             ),             body:PersonalInformationBlocProvider(               movieBloc: PersonalInformationBloc(),               child: TabBarView(                 children: [                   MyInformation(),                   new SmallCalendarExample(),                 ],               ),             ),           ),         );       }     }          class MyInformation extends StatelessWidget{       // TODO: implement build       var deviceSize;            //Column1       Widget profileColumn(PersonalInformation snapshot) => Container(         height: deviceSize.height * 0.24,         child: Column(           mainAxisAlignment: MainAxisAlignment.center,           children: <Widget>[             Row(               mainAxisAlignment: MainAxisAlignment.spaceEvenly,               children: <Widget>[                 Container(                   decoration: BoxDecoration(                     borderRadius:                     new BorderRadius.all(new Radius.circular(50.0)),                     border: new Border.all(                       color: Colors.black,                       width: 4.0,                     ),                   ),                   child: CircleAvatar(                     backgroundImage: NetworkImage(                         "http://www.binaythapa.com.np/img/me.jpg"),                     foregroundColor: Colors.white,                     backgroundColor: Colors.white,                     radius: 40.0,                   ),                 ),                 ProfileTile(                   title: snapshot.firstName,                   subtitle: "Developer",                 ),                 SizedBox(                   height: 10.0,                 ),               ],             )           ],         ),       );       Widget bodyData(PersonalInformation snapshot) {         return SingleChildScrollView(             child: Column(               children: <Widget>[                 profileColumn(snapshot)               ],             ),         );       }                 @override       Widget build(BuildContext context) {         final personalInformationBloc = PersonalInformationBlocProvider.of(context);              deviceSize = MediaQuery.of(context).size;         return StreamBuilder(             stream: personalInformationBloc.results,             builder: (context,snapshot){               if (!snapshot.hasData)                 return Center(                   child: CircularProgressIndicator(),                 );               return bodyData(snapshot.data);             }         );       }     }      

I am using Bloc Pattern for retrieving data from Rest API (just called the whole object from JSON and parsed user name only). The Page consists of two tabs MyInformation and SmallCalendar. When the app runs the data are fetched correctly and everything is good. When I go to tab two and return to tab one then the whole screens in tab one goes to red showing error: Bad state: Stream has already been listened to.

Answer 1

You should use the following.

StreamController<...> _controller = StreamController<...>.broadcast();