Observer class

A reactive widget that rebuilds whenever any accessed Observable changes.

This is a simplified version of ContextObserver that doesn't provide the BuildContext to the builder function.

Use this when you don't need context inside the builder and just want pure reactive rebuilding based on Observable values.

Example usage:

Observer(() {
  final count = counterObservable.watch();
  return Text('$count');
});
Inheritance

Constructors

Observer.new(ObserverBuilder builder, {Key? key, bool shouldRebuild()?})
Creates an Observer that listens for changes in observed values.
const

Properties

builder ObserverBuilder
The builder function that returns the widget tree.
final
hashCode int
The hash code for this object.
no setterinherited
key Key?
Controls how one widget replaces another widget in the tree.
finalinherited
runtimeType Type
A representation of the runtime type of the object.
no setterinherited
shouldRebuild bool Function()?
final

Methods

createElement() StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() State<Observer>
Creates the mutable state for this widget at a given location in the tree.
override
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