FocusTraversalGroupModifier 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.

{@tool dartpad} 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.

** See code in examples/api/lib/widgets/focus_traversal/focus_traversal_group.0.dart ** {@end-tool}

See also:

• FocusNode, for a description of the focus system.
• WidgetOrderTraversalPolicy, a policy that relies on the widget creation order to describe the order of traversal.
• ReadingOrderTraversalPolicy, a policy that describes the order as the natural "reading order" for the current Directionality.
• DirectionalFocusTraversalPolicyMixin a mixin class that implements focus traversal in a direction.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• SingleChildStatelessModifier
• FocusTraversalGroupModifier

Available extensions

• ModifierTransformer

Constructors

FocusTraversalGroupModifier({Key? key, Widget? child, Key? modifierKey, FocusTraversalPolicy? policy, bool descendantsAreFocusable = true, bool descendantsAreTraversable = true})

Creates a FocusTraversalGroup object.

Properties

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 setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

modifierKey → Key?

The actual key of the widget, which Modifier wrapped

final, inherited

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 setter, inherited

Methods

build(BuildContext context) → Widget

Describes the part of the user interface represented by this widget.

inherited

buildWithChild(BuildContext context, Widget? child) → Widget

A build method that receives an extra child parameter.

override

createElement() → SingleChildStatelessElement

Create a SingleChildStatelessElement

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}) → 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