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

Constructors

TReactiveSelector({required ValueListenable<T> listenable, required S selector(T v), 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 v): Function to select a value from the listenable.
final

Methods

box({double minW = 0.0, double minH = 0.0, double maxW = double.infinity, double maxH = double.infinity}) → Widget: Available on Widget, provided by the WidgetX extension
Wraps this widget in a ConstrainedBox to apply layout constraints.
center({bool when = true}) → Widget: Available on Widget, provided by the WidgetX extension
Wraps this widget in a Center widget.
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
expanded({int flex = 1}) → Widget: Available on Widget, provided by the WidgetX extension
Wraps this widget in an Expanded widget.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
padding([double left = 0.0, double top = 0.0, double right = 0.0, double bottom = 0.0]) → Widget: Available on Widget, provided by the WidgetX extension
Wraps this widget in a Padding with flexible edge control.
paddingSymmetric({double h = 0.0, double v = 0.0}) → Widget: Available on Widget, provided by the WidgetX extension
Wraps this widget in a Padding with symmetric horizontal and vertical spacing.
size({double? w, double? h}) → Widget: Available on Widget, provided by the WidgetX extension
Wraps this widget in a SizedBox to apply fixed width and/or height.
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
visible(bool visible, {bool maintainState = false}) → Widget: Available on Widget, provided by the WidgetX extension
Wraps this widget in a Visibility widget.
when(bool condition) → Widget: Available on Widget, provided by the WidgetX extension
Returns this widget if condition is true, otherwise returns SizedBox.shrink(). Usage: Text('Hello').when(isVisible)

Operators

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

TReactiveSelector<T, S> class

Basic Usage

With Complex State

Constructors

Properties

Methods

Operators

reactive_selector library