EventEmitter class Null safety
This class provides necessary implementations for subscribing and cancelling the event subscriptions and publishing events to the subcribers.
) → void
- Clear all subscribers from the cache.
String event, [Object? sender, 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.
sender- The sender who published the event. Ignore if not required.
data- Data the event need to carry. Ignore this argument if no data needs to be sent.
String event) → int
- Get the list of subscribers for a particular event.
Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed. [...]
Listener? 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.
String event, Object? context, EventCallback callback) → Listener
API to register for notification.
It is mandatory to pass event name and callback parameters.
event- Event name used for the subscription. A valid event name is mandatory.
context- Context information, which need to be sent in all emitted events.
callback- EventCallback function registered to receive events emitted from the publisher. A valid callback function is mandatory.
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.
String 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 name used during subscription.
String eventName, EventCallback callback) → void
Unsubscribe from getting any future events from emitter.
This mechanism uses event name and callback to unsubscribe from all possible events.
eventName- Event name for the subscription.
callback- EventCallback used when registering subscription using on function.
) → String
A string representation of this object. [...]