KeyValueListenable<K, V> class abstract

An interface for a KeyValueNotifer that exposes a value.

This is not a subtype of ValueListenable or AdvancedValueListenable, because the Listenable.addListener, Listenable.removeListener, AdvancedValueListenable.addValueListener and AdvancedValueListenable.removeValueListener methods require a different signature in a KeyValueListenable.

Implementers

Constructors

KeyValueListenable()
const

Properties

hashCode → int
The hash code for this object.
no setterinherited
hasListeners → bool
no setter
isEmpty → bool?
If the internal NotifierBase is an EmptyValueNotifier, you can check if it is empty.
no setter
isNotEmpty → bool?
If the internal NotifierBase is an EmptyValueNotifier, you can check if it is not empty.
no setter
keys → Iterable<K>
no setter
notifierType → Type
Get the Type of the underlying NotifierBase.
no setter
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
value → V
The current value of the object. When the value changes, the callbacks registered with addListener and addValueListener will be invoked.
no setter

Methods

addListener(K key, VoidCallback listener) → bool
Returns true if key was not already used for another listener.
addValueListener(K key, ValueCallback<V> listener) → bool
Returns true if key was not already used for another listener.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
removeListener(K key) → bool
Returns true if key was used for a listener and therefore successfully removed.
removeValueListener(K key) → bool
Returns true if key was used for a listener and therefore successfully removed.
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited