IndexedSemantics 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.

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.
link 
ListView(
  addSemanticIndexes: false,
  semanticChildCount: 2,
  children: const <Widget>[
    IndexedSemantics(index: 0, child: Text('First')),
    Spacer(),
    IndexedSemantics(index: 1, child: Text('Second')),
    Spacer(),
  ],
)

See also:

Inheritance

Constructors

IndexedSemantics.new({Key? key, required int index, Widget? child})
Creates a widget that annotated the first child semantics node with an index.
const

Properties

child → Widget?
The widget below this widget in the tree.
finalinherited
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
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

createElement() → SingleChildRenderObjectElement
RenderObjectWidgets always inflate to a RenderObjectElement subclass.
inherited
createRenderObject(BuildContext context) → RenderIndexedSemantics
Creates an instance of the RenderObject class that this RenderObjectWidget represents, using the configuration described by this RenderObjectWidget.
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
didUnmountRenderObject(covariant RenderObject renderObject) → void
This method is called when a RenderObject that was previously associated with this widget is removed from the render tree. The provided RenderObject will be of the same type as the one created by this widget's createRenderObject method.
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
updateRenderObject(BuildContext context, covariant RenderIndexedSemantics renderObject) → void
Copies the configuration described by this RenderObjectWidget to the given RenderObject, which will be of the same type as returned by this object's createRenderObject.
override

Operators

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