Listener class
Listener is one who listen for specific event. Listener register for notification with EventEmitter Once the listener is registered, a Listener interface is returned back to the caller. Caller can use this Listener interface to cancel the registration or check the state.
Constructors
- Listener(String eventName, Object? context, EventCallback callback, CancelEvent? _cancelCallback)
-
Constructor for Listener.
This will take four arguments.
eventName, callback are mandatory.
context,
_cancelCallback
are optional. if_cancelCallback
callback is provided, then the listener can use that to cancel the subscription. - Listener.Default(String eventName, Object? context, EventCallback callback)
- Constructor for Listener. This will take four arguments. eventName, callback are mandatory. context is optional.
Properties
- callback → EventCallback
-
The event callback, which the subscriber uses when he register it for.
final
- context → Object?
-
The context from which subscriber is interested in.
final
- eventName → String
-
The event name, the subscriber subscribed to.
final
- hashCode → int
-
The hash code for this object.
no setterinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
Methods
-
cancel(
) → bool - Cancel the event subscription with the subject. Eventhough the cancel method is called, listener doesn't check the cancellation of the subscription. Subscription cancellation shall be implemented in the _cancelCallback function. The Default constructor doesn't provide a mechanism to cancel the subscription. Use the EventEmitter.on to cancel the suscrition effectively. Returns true, if _cancelCallback is successfully executed, false otherwise.
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
toString(
) → String -
A string representation of this object.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited