BlocObserver

Global observer that receives lifecycle notifications from every Bloc and Cubit in the app.

Set a custom subclass once at app startup, before any Blocs are created:

class App : Application() {
    override fun onCreate() {
        super.onCreate()
        BlocObserver.shared = AppBlocObserver()
    }
}

Hook summary

Hook	When it fires	Emitter type
onCreate	Emitter is initialised	Bloc + Cubit
onEvent	Before an event is dispatched	Bloc only
onChange	After every `emit()`	Bloc + Cubit
onTransition	After a synchronous `emit()` with event context	Bloc only
onError	When `addError()` is called	Bloc + Cubit
onClose	When `close()` is called	Bloc + Cubit

Always call super in every override so the chain remains intact as the library grows.

Constructors

BlocObserver

constructor()

Types

Companion

object Companion

Functions

onChange

open fun <S : Any> onChange(emitter: StateEmitter<S>, change: Change<S>)

Called after every Cubit.emit / Bloc.emit, with a Change containing the previous and next states.

onClose

open fun <S : Any> onClose(emitter: StateEmitter<S>)

Called when Cubit.close / Bloc.close completes.

onCreate

open fun <S : Any> onCreate(emitter: StateEmitter<S>)

Called immediately after a Cubit or Bloc is constructed.

onError

open fun <S : Any> onError(emitter: StateEmitter<S>, error: Throwable)

Called whenever Cubit.addError / Bloc.addError is invoked.

onEvent

open fun <S : Any, E : Any> onEvent(bloc: Bloc<S, E>, event: E)

Called immediately before an event is dispatched to its handler. Only fires for Bloc subclasses, not Cubit.

onTransition

open fun <S : Any, E : Any> onTransition(bloc: Bloc<S, E>, transition: Transition<E, S>)

Called after a synchronous Bloc.emit that was triggered by an event handler. Async emissions (those inside a launched coroutine) reach onChange but not here.