IndexedSemanticsModifier class
A widget that annotates the child semantics with an index.
Semantic indexes are used by TalkBack/Voiceover to make announcements about the current scroll state. Certain widgets like the ListView will automatically provide a child index for building semantics. A user may wish to manually provide semantic indexes if not all child of the scrollable contribute semantics.
{@tool snippet}
The example below handles spacers in a scrollable that don't contribute semantics. The automatic indexes would give the spaces a semantic index, causing scroll announcements to erroneously state that there are four items visible.
ListView(
addSemanticIndexes: false,
semanticChildCount: 2,
children: const <Widget>[
IndexedSemantics(index: 0, child: Text('First')),
Spacer(),
IndexedSemantics(index: 1, child: Text('Second')),
Spacer(),
],
)
{@end-tool}
See also:
- CustomScrollView, for an explanation of index semantics.
- Inheritance
-
- Object
- DiagnosticableTree
- Widget
- StatelessWidget
- SingleChildStatelessModifier
- IndexedSemanticsModifier
- Available extensions
Constructors
- IndexedSemanticsModifier({Key? key, Key? modifierKey, required int index, Widget? child})
-
Creates a widget that annotated the first child semantics node with an index.
const
Properties
- hashCode → int
-
The hash code for this object.
no setterinherited
- index → int
-
The index used to annotate the first child semantics node.
final
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- modifierKey → Key?
-
The actual key of the widget, which Modifier wrapped
finalinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
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