TReactiveSelector<T, S> class

A reactive widget that rebuilds only when selected value changes.

TReactiveSelector provides efficient rebuilds with:

  • Selective listening to ValueListenable
  • Only rebuilds when selector result changes
  • Access to old and new values
  • Performance optimization for complex state

Basic Usage

final counter = ValueNotifier<int>(0);

TReactiveSelector<int, bool>(
  listenable: counter,
  selector: (count) => count > 10,
  builder: (context, isAboveTen, oldValue) {
    return Text(isAboveTen ? 'High' : 'Low');
  },
)

With Complex State

final user = ValueNotifier<User>(currentUser);

TReactiveSelector<User, String>(
  listenable: user,
  selector: (user) => user.name,
  builder: (context, name, oldName) {
    if (oldName != null && oldName != name) {
      print('Name changed from \$oldName to \$name');
    }
    return Text('Hello, \$name');
  },
)

Type parameters:

  • T: The type of the listenable value
  • S: The type of the selected value

See also:

Inheritance

Constructors

TReactiveSelector({required ValueListenable<T> listenable, required S selector(T), required Widget builder(BuildContext context, S value, S? oldValue), Key? key})
Creates a reactive selector.
const

Properties

builder → Widget Function(BuildContext context, S value, S? oldValue)
Builder that receives the selected value and old value.
final
hashCode → int
The hash code for this object.
no setterinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
listenable → ValueListenable<T>
The value listenable to watch.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
selector → S Function(T)
Function to select a value from the listenable.
final

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<StatefulWidget>
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