BaseCubit<T> class abstract

A Cubit for screens that load data of type T and run actions.

• load fetches the screen's data: emits DataLoading, then DataSuccess or DataFailed. Concurrent loads are safe: only the latest one's result is emitted.
• runAction runs a one-shot action (submit, delete, like): emits ActionLoading, then ActionSuccess or ActionFailed. Errors never escape as unhandled exceptions.
• The emit* helpers and updateData let you manage the state yourself.
• observe gives a section of the screen its own independent state.

Every error from load and runAction goes through onError, so override it (calling super) to log or report errors.

Nothing is emitted after close, so late responses are harmless.

Constructors

BaseCubit([DataState<T>? initialState])

Creates the cubit, starting at initialState (default DataInitial).

Properties

buildState → BuildState<T>

The last state the screen rendered.

no setter

cache → SoftCache

In-memory cache used by load and observe.

final

data → T?

The data on screen, or null if not loaded.

no setter

hashCode → int

The hash code for this object.

no setter, inherited

isClosed → bool

Whether the bloc is closed.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

state → DataState<T>

The current state.

no setter, inherited

stream → Stream<DataState<T>>

The current stream of states.

no setter, inherited

Methods

addError(Object error, [StackTrace? stackTrace]) → void

Reports an error which triggers onError with an optional StackTrace.

inherited

close() → Future<void>

Closes the instance. This method should be called when the instance is no longer needed. Once close is called, the instance can no longer be used.

emit(DataState<T> state) → void

Updates the state to the provided state. emit does nothing if the state being emitted is equal to the current state.

inherited

emitData(T data) → void

Shows data.

emitError(Object error, [StackTrace? stackTrace]) → void

Shows error.

emitLoading() → void

Shows DataLoading.

emitState(DataState<T> state) → void

Emits any state, including your own BuildState/ActionState subclasses. Cancels any load in flight when state is a BuildState, so a late response does not overwrite it.

load(Future<T> request(), {String? cacheKey, Duration? cacheTtl, bool forceRefresh = false, bool keepDataWhileLoading = false}) → Future<void>

Loads the screen's data with request.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

observe<R>(String tag, Future<R> request(), {String? cacheKey, Duration? cacheTtl, bool forceRefresh = false}) → DataObserver<R>

Loads request into the observer for tag and returns the observer.

observer<R>(String tag) → DataObserver<R>

Returns the observer for tag, creating it on first use.

onChange(Change<DataState<T>> change) → void

Called whenever a change occurs with the given change. A change occurs when a new state is emitted. onChange is called before the state of the cubit is updated. onChange is a great spot to add logging/analytics for a specific cubit.

inherited

onError(Object error, StackTrace stackTrace) → void

Called whenever an error occurs and notifies BlocObserver.onError.

inherited

runAction<R>(Future<R> action(), {void onSuccess(R result)?}) → Future<ActionResult<R>>

Runs a one-shot action and returns its ActionResult.

toString() → String

A string representation of this object.

inherited

updateData(T update(T current)) → void

Changes the data on screen without a request, e.g. to append an item or flip a flag after an action. Does nothing if no data is loaded.

Operators

operator ==(Object other) → bool

The equality operator.

inherited