WithValue<T> class

A Flutter widget that inherits from InheritedWidget to provide a specific value down the widget tree.

This widget is generic and can be used with any type of value. It is particularly useful for providing data directly to multiple widgets in the subtree without having to pass the data through multiple widget constructors.

Generics: T - The type of the value being provided down the widget tree.

Parameters: value - The data value to be provided to the widgets in the subtree. IMPORTANT: To ensure proper functionality, if the value is not a primitive type, it should override the == and hashCode methods. child - The widget below this widget in the tree. This widget can access the provided value. key - An optional key that controls how one widget replaces another widget in the tree.

WithValue includes WithValue.of to retrieve the nearest WithValue up the widget tree and return its value. If the InheritedWidget is not found, a AssertionError is thrown.

Example Usage:

WithValue<int>(
  value: 42,
  child: MyWidget(),
)

To retrieve the value:

// Access the value in a descendant widget
int value = WithValue.of<int>(context);

Inheritance

Constructors

WithValue.new({required Widget child, required T value, Key? key}): const

Properties

child → Widget: The widget below this widget in the tree.
finalinherited
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
value → T: The value provided to the subtree.
final

Methods

createElement() → InheritedElement: Inflates this configuration to a concrete instance.
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
updateShouldNotify(covariant WithValue<T> oldWidget) → bool: IMPORTANT: To ensure proper functionality if value is not a primitive type it should override the == and hashCode methods.
override

Operators

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

Static Methods

maybeOf<T>(BuildContext context) → T?: Attempts to retrieve the value of type T from the nearest ancestor WithValue widget.
of<T>(BuildContext context) → T: Retrieves the value of type T from the nearest ancestor WithValue widget.