ObservableListener<T> class

A stateless widget that listens to an observable and triggers the provided listener callback whenever the value changes.

Unlike ObservableConsumer, this widget does not rebuild itself. It is meant for side effects only (e.g., showing dialogs, triggering actions).

Usage: ObservableListener( observable: counter, listener: (context, value) { if (value > 10) { ScaffoldMessenger.of(context).showSnackBar(...); } }, child: MyWidget(), );

Inheritance

Constructors

ObservableListener({Key? key, required IObservableListenable<T> observable, required void listener(BuildContext context, T value), required Widget? child})
Creates an ObservableListener that listens to observable and calls listener when its value changes.
const

Properties

child → Widget?
The child widget to render. It does not rebuild on value change.
final
hashCode → int
The hash code for this object.
no setterinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
listener → void Function(BuildContext context, T value)
The callback that is triggered when the observable emits a new value.
final
observable → IObservableListenable<T>
The observable to listen to.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

build(BuildContext context) → Widget
Describes the part of the user interface represented by this widget.
override
createElement() → StatelessElement
Creates a StatelessElement to manage this widget's location in the tree.
inherited
debugDescribeChildren() → List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
inherited
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String
A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug, int wrapWidth = 65}) → String
Returns a string representation of this node and its descendants.
inherited
toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String
Returns a one-line detailed description of the object.
inherited
toStringShort() → String
A short, textual description of this widget.
inherited

Operators

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