Listenable class abstract

An object that maintains a list of listeners.

The listeners are typically used to notify clients that the object has been updated.

The terms "notify clients", "send notifications", "trigger notifications", and "fire notifications" are used interchangeably.

See also:

• ValueListenable, an interface that augments the Listenable interface with the concept of a current value.
• ChangeNotifier, which can be subclassed or mixed in to create objects that implement the Listenable interface.
• ValueNotifier, which implements the ValueListenable interface with a mutable value that triggers the notifications when modified.
• Listenable.merge, which creates a Listenable that triggers notifications whenever any of a list of other Listenables trigger their notifications.

Constructors

Listenable()

This constructor enables subclasses to provide const constructors so that they can be used in const expressions.

const

Listenable.merge(Iterable<Listenable?> listenables)

Return a Listenable that triggers when any of the given Listenables themselves trigger.

factory

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

addListener(VoidCallback listener) → void

Register a closure to be called when the object notifies its listeners.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

removeListener(VoidCallback listener) → void

Remove a previously registered closure from the list of closures that the object notifies.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited

Static Properties

debugMaybeDispatchCreated ↔ ObjectCreatedCallback

Called when a new object is created.

getter/setter pair

debugMaybeDispatchDisposed ↔ ObjectDisposedCallback

Called when an object is disposed.

getter/setter pair

onError ↔ ErrorCallback

Error callback that is called when an error is thrown by a listener or assertion.

getter/setter pair