ContextStorage class

A widget for creating a storage in the widget tree, accessible to child widgets through the InheritedWidget mechanism.

Use case: in your application you have a bottom tab navigation with global sections, and inside the bottom tabs there is a nested navigation with its own tabs. If you want to store some data for nested tabs, but clear the storage when switching global sections, then ContextStorage will help.

Example:

// Wrap nested tabs in context storage:
@override
Widget build(BuildContext context) {
  return ContextStorage(
    child: DefaultTabController(
      length: 2,
      child: Scaffold(
        appBar: AppBar(
          title: Text('Home'),
          bottom: TabBar(
            tabs: [
              // Tab definitions here...
            ],
          ),
        ),
        body: TabBarView(
          children: [
            // Tab bodies here...
          ],
        ),
      ),
    ),
  );
}

// Now inside the tab body widgets you can read
// the value from the storage...
_value = context.storage?.get<int>('counter') ?? 0;

// ...and write the value to the storage.
context.storage?.set('counter', _value);

Inheritance

Constructors

ContextStorage({Key? key, String? name, required Widget child}): Creates a ContextStorage widget.
const

Properties

child → Widget: The widget below this widget in the 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
name → String?: Name for the storage, optional.
final
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited

Methods

createElement() → StatefulElement: Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → ContextStorageState: 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}) → 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

Static Methods

of(BuildContext context, [String? name]) → ContextStorageState?: Returns the closest ContextStorageState which encloses the given context.