flutter_bloc - hook into onClose, onCreate lifecycle events for specific cubit - flutter

Question

I want to hook into the lifecycle events of my cubits.
I notice the blocObserver has onClose and onCreate, however that is for observing all cubit's lifecycle events. How do I hook into these events just for a specific cubit? For example the equivalent of overriding onClose inside a cubit.
My implementation of ChessMax's answer:
class VpCubit<T> extends Cubit<T> {
VpCubit(T initial) : super(initial);
void onClose() => print('');
#override
Future<void> close() async {
if (onClose != null) {
onClose();
}
return super.close();
}
}
class LoggedOutNickNameCubit extends VpCubit<int> {
LoggedOutNickNameCubit()
: super(0);
#override
void onClose() {
print('closing');
}
void onCreate() {
print('creating');
}
}

Answer 1

One possible solution is to filter out events in the observing hook. Every event of BlocObserver has a reference to a cubit/bloc instance that sends the event. So you can compare it with the reference with your specific cubit/bloc instance. And if references are equal you can handle it somehow. Something like this:
class MyObserver extends BlocObserver {
final Cubit<Object> _cubit;
MyObserver(this._cubit) : assert(_cubit != null);
#override
void onClose(Cubit cubit) {
if (cubit == _cubit) {
// do whatever you need
}
super.onClose(cubit);
}
}
Another way is to create your own cubit/bloc subclass. Override the methods you want to listen to. And use your own BlocObserver like class to notify this specific cubit/bloc listeners. Something like this:
class MyObserver {
final void Function() onClose;
MyObserver(this.onClose);
}
class MyBloc extends Bloc<MyEvent, MyState> {
final MyObserver _observer;
MyBloc(this._observer) : super(MyInitial());
#override
Future<void> close() async {
if (_observer != null && _observer.onClose != null) {
_observer.onClose();
}
return super.close();
}
}
Also, I think, it's possible to write a generic cubit/bloc wrapper base class like above. And then use it as a base class for all your cubits/blocs classes instead.