FocusTraversalGroup class

A widget that describes the inherited focus policy for focus traversal for its descendants, grouping them into a separate traversal group.

A traversal group is treated as one entity when sorted by the traversal algorithm, so it can be used to segregate different parts of the widget tree that need to be sorted using different algorithms and/or sort orders when using an OrderedTraversalPolicy.

Within the group, it will use the given policy to order the elements. The group itself will be ordered using the parent group's policy.

By default, traverses in reading order using ReadingOrderTraversalPolicy.

To prevent the members of the group from being focused, set the descendantsAreFocusable attribute to false.

This sample shows three rows of buttons, each grouped by a FocusTraversalGroup, each with different traversal order policies. Use tab traversal to see the order they are traversed in. The first row follows a numerical order, the second follows a lexical order (ordered to traverse right to left), and the third ignores the numerical order assigned to it and traverses in widget order.

To create a local project with this code sample, run:
flutter create --sample=widgets.FocusTraversalGroup.1 mysample

Constructors

FocusTraversalGroup({Key? key, FocusTraversalPolicy? policy, bool descendantsAreFocusable = true, bool descendantsAreTraversable = true, required Widget child}): Creates a FocusTraversalGroup object.

Properties

child → Widget: The child widget of this FocusTraversalGroup.
final
descendantsAreFocusable → bool: If false, will make this widget's descendants unfocusable.
final
descendantsAreTraversable → bool: If false, will make this widget's descendants untraversable.
final
hashCode → int: The hash code for this object.
no setterinherited
key → Key?: Controls how one widget replaces another widget in the tree.
finalinherited
policy → FocusTraversalPolicy: The policy used to move the focus from one focus node to another when traversing them using a keyboard.
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() → State<FocusTraversalGroup>: 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.
override
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

maybeOf(BuildContext context) → FocusTraversalPolicy?: Returns the FocusTraversalPolicy that applies to the FocusNode of the nearest ancestor Focus widget, or null, given a BuildContext.
maybeOfNode(FocusNode node) → FocusTraversalPolicy?: Returns the FocusTraversalPolicy that applies to the nearest ancestor of the given FocusNode.
of(BuildContext context) → FocusTraversalPolicy: Returns the FocusTraversalPolicy that applies to the FocusNode of the nearest ancestor Focus widget, given a BuildContext.