ValueNotifierWrapper<T> class

A StatefulWidget that manages a ValueNotifier and provides it to its child builder.

ValueNotifierWrapper simplifies working with ValueNotifier by handling its creation, disposal, and optionally reacting to value changes via onChange. This widget is useful for local, ephemeral state that doesn't require a full-blown state management solution, and for building simple, reactive UI patterns.

The child builder receives the ValueNotifier so it can be used with widgets like ValueListenableBuilder.

Example

ValueNotifierWrapper<int>(
  initialValue: 0,
  onChange: (value) => print('Value changed: $value'),
  child: (notifier) => ValueListenableBuilder<int>(
    valueListenable: notifier,
    builder: (context, value, _) => Text('Current value: $value'),
  ),
)

See also:

• ValueNotifier, a simple class for holding a single value and notifying listeners.
• ValueListenableBuilder, which rebuilds when a ValueListenable changes.
• StreamControllerWrapper, for managing a StreamController in a similar pattern.
• CallbackWidgetBuilder, the typedef used for the child builder.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatefulWidget
• ValueNotifierWrapper

Constructors

ValueNotifierWrapper({required T initialValue, required CallbackWidgetBuilder<ValueNotifier<T>> child, ValueChanged<T>? onChange, Key? key})

Creates a ValueNotifierWrapper.

const

Properties

child → CallbackWidgetBuilder<ValueNotifier<T>>

Called to build the widget subtree and provides the ValueNotifier.

final

hashCode → int

The hash code for this object.

no setter, inherited

initialValue → T

The initial value for the ValueNotifier.

final

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

onChange → ValueChanged<T>?

Callback called when the ValueNotifier value changes.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

createElement() → StatefulElement

Creates a StatefulElement to manage this widget's location in the tree.

inherited

createState() → State<ValueNotifierWrapper<T>>

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