EventEmitter<T> class
This class provides necessary implementations for subscribing and cancelling the event subscriptions and publishing events to the subcribers.
Constructors
Properties
Methods
-
clear(
) → void - Clear all subscribers from the cache.
-
emit(
T event, [Object? data]) → void -
API to emit events.
event is a required parameter.
If sender information is sent, it will be used to intimate user about it.
event
- What event needs to be emitted.data
- Data the event need to carry. Ignore this argument if no data needs to be sent. -
getListenersCount(
String event) → int - Get the list of subscribers for a particular event.
-
listen(
T event, EventCallback callback, bool isOnce) → Listener< T> -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
off(
Listener< T> ? listener) → void -
Remove event listener from emitter.
This will unsubscribe the caller from the emitter from any future events.
Listener should be a valid instance.
listener
- Listener instance to be removed from the event subscription. -
on(
T event, EventCallback callback) → Listener< T> -
API to register for notification.
It is mandatory to pass event and callback parameters.
event
- Event used for the subscription. A valid event is mandatory.callback
- EventCallback function registered to receive events emitted from the publisher. A valid callback function is mandatory. -
once(
T event, EventCallback callback) → Listener< T> -
removeAllByCallback(
EventCallback callback) → void -
Remove all listeners which matches with the callback provided.
It is possible to register for multiple events with a single callback.
This mechanism ensure that all event registrations would be cancelled which matches the callback.
callback
- The event callback used during subscription. -
removeAllByEvent(
T event) → void -
Use this mechanism to remove all subscription for a particular event.
Caution : This will remove all the listeners from multiple files or classes or modules.
Think twice before calling this API and make sure you know what you are doing!!!
event
- Event used during subscription. -
removeListener(
T event, EventCallback callback) → void -
Unsubscribe from getting any future events from emitter.
This mechanism uses event and callback to unsubscribe from all possible events.
event
- Event for the subscription.callback
- EventCallback used when registering subscription using on function. -
toString(
) → String -
A string representation of this object.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited