Semantics class
A widget that annotates the widget tree with a description of the meaning of the widgets.
Used by assistive technologies, search engines, and other semantic analysis software to determine the meaning of the application.
See also:
- SemanticsProperties, which contains a complete documentation for each of the constructor parameters that belongs to semantics properties.
- RenderObject.describeSemanticsConfiguration, the rendering library API through which the Semantics widget and SliverSemantics sliver are actually implemented.
- SemanticsNode, the object used by the rendering library to represent semantics in the semantics tree.
- SemanticsDebugger, an overlay to help visualize the semantics tree. Can be enabled using WidgetsApp.showSemanticsDebugger, MaterialApp.showSemanticsDebugger, or CupertinoApp.showSemanticsDebugger.
- MergeSemantics, a widget which marks a subtree as being a single node for accessibility purposes.
- ExcludeSemantics, a widget which excludes a subtree from the semantics tree (which might be useful if it is, e.g., totally decorative and not important to the user).
- SliverSemantics, the sliver variant of this widget.
- Inheritance
- Annotations
Constructors
- Semantics.new({Key? key, Widget? child, bool container = false, bool explicitChildNodes = false, bool excludeSemantics = false, bool blockUserActions = false, bool? enabled, bool? checked, bool? mixed, bool? selected, bool? toggled, bool? button, bool? slider, bool? keyboardKey, bool? link, Uri? linkUrl, bool? header, int? headingLevel, bool? textField, bool? readOnly, bool? focusable, bool? focused, bool? inMutuallyExclusiveGroup, bool? obscured, bool? multiline, bool? scopesRoute, bool? namesRoute, bool? image, bool? liveRegion, bool? expanded, bool? isRequired, int? maxValueLength, int? currentValueLength, String? identifier, String? label, AttributedString? attributedLabel, String? value, AttributedString? attributedValue, String? increasedValue, AttributedString? attributedIncreasedValue, String? decreasedValue, AttributedString? attributedDecreasedValue, String? hint, AttributedString? attributedHint, String? tooltip, String? onTapHint, String? onLongPressHint, TextDirection? textDirection, SemanticsSortKey? sortKey, SemanticsTag? tagForChildren, VoidCallback? onTap, VoidCallback? onLongPress, VoidCallback? onScrollLeft, VoidCallback? onScrollRight, VoidCallback? onScrollUp, VoidCallback? onScrollDown, VoidCallback? onIncrease, VoidCallback? onDecrease, VoidCallback? onCopy, VoidCallback? onCut, VoidCallback? onPaste, VoidCallback? onDismiss, MoveCursorHandler? onMoveCursorForwardByCharacter, MoveCursorHandler? onMoveCursorBackwardByCharacter, SetSelectionHandler? onSetSelection, SetTextHandler? onSetText, VoidCallback? onDidGainAccessibilityFocus, VoidCallback? onDidLoseAccessibilityFocus, VoidCallback? onFocus, Map<
CustomSemanticsAction, VoidCallback> ? customSemanticsActions, SemanticsRole? role, Set<String> ? controlsNodes, SemanticsValidationResult validationResult = SemanticsValidationResult.none, SemanticsInputType? inputType, Locale? localeForSubtree}) - Creates a semantic annotation.
- Semantics.fromProperties({Key? key, Widget? child, bool container = false, bool explicitChildNodes = false, bool excludeSemantics = false, bool blockUserActions = false, Locale? localeForSubtree, required SemanticsProperties properties})
- Creates a semantic annotation using SemanticsProperties. const
Properties
- blockUserActions → bool
- Whether to block user interactions for the rendering subtree. finalinherited
- child → Widget?
- The widget below this widget in the tree. finalinherited
- container → bool
- If
containeris true, this widget will introduce a new node in the semantics tree. Otherwise, the semantics will be merged with the semantics of any ancestors (if the ancestor allows that).finalinherited - excludeSemantics → bool
- Whether to replace all child semantics with this node. finalinherited
- explicitChildNodes → bool
- Whether descendants of this widget are allowed to add semantic information to the SemanticsNode annotated by this widget. finalinherited
- hashCode → int
- The hash code for this object. no setterinherited
- key → Key?
- Controls how one widget replaces another widget in the tree. finalinherited
- localeForSubtree → Locale?
- The Locale for widgets in the subtree. finalinherited
- properties → SemanticsProperties
- Contains properties used by assistive technologies to make the application more accessible. 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) → RenderSemanticsAnnotations - 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 RenderSemanticsAnnotations 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