How to update state of widgets using bloc in flutter? - flutter

Question

I have 2 widgets on a screen - A and B. There is an event
performed on widget B, on which the state of A and B should
get updated.
I have used different blocs and states for each of them and used the approach of Futures to get data from api while loading the screen.
On an event of widget B, how can I update state of both the widgets A and B without calling the api again as I can get the data from previous session and also from the response of event on widget B, it is possible to build the state on the UI itself.
Adding code:
class BlocA extends Bloc<BlocAEvent,BlocAState>
{
BlocA():super(InitialState()){
on<GetData>(_getBlocAData);
}
}
void _getBlocAData(GetData event, Emitter<BlocAState>emit)
async{
try {
List<User> getDataResponse = await
DataService().getWidgetAData(
event.userid);
emit(BlocALoadedState(BlocAData: getDataResponse));
}
catch(e){
rethrow;
}}
class InitialState extends BlocAState{}
class BlocALoadedState extends BlocAState{
final List<User> BlocAData;
BlocALoadedState({required this.BlocAData});
}
BlocB:
abstract class BlocBStates {}
class BlocBLoadedState extends BlocBStates{
List<User> BlocBdata;
BlocBLoadedState({required this.BlocBdata});
}
class BlocBAcceptedState extends BlocBStates{
User user;
BlocBAcceptedState({required this.user});
}
Now, BlocB has event which fetches data from a different
enter code heresource.
class BlocB extends Bloc<BlocBEvent,BlocBState>
{
BlocB():super(InitialState()){
on<GetData>(_getBlocBData);
on<BlocBevent>(_onClickofaButtoninWidgetB);
}
}
void _getBlocBData(GetData event,
Emitter<BlocBState>emit)
async{
try {
List<User> getDataResponse = await
DataService().getWidgetBData(
event.userid);
emit(BlocBLoadedState(BlocBData: getDataResponse));
}
catch(e){
rethrow;
}}
void _onClickofaButtoninWidgetB(BlocBevent event,
Emitter<BlocBStates>emit) {
User blocBEventResponse = await
DataService().acceptRequest(
event.senderId,event.receiverId)
// From this response, I want to add this entry to bloc A's
// state and remove from bloc B's state
}

Answer 1

use BlocListener
BlocProvider(
create: BlocA(),
child: BlocListener<BlocB, StateB>(
listener: (context, state) {
if (state is StateBLoading) {
context.read<BlocA>().add(EventALoading());
} else if (state is StateBLoaded) {
context.read<BlocA>().add(EventALoaded(state.someData));
}
},
child: WidgetA();
);
}