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.
- MergeSemantics, which marks a subtree as being a single node for accessibility purposes.
- ExcludeSemantics, 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).
- RenderObject.describeSemanticsConfiguration, the rendering library API through which the Semantics widget is 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.
- Inheritance
- Annotations
Constructors
-
Semantics({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, 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, 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}) - Creates a semantic annotation.
- Semantics.fromProperties({Key? key, Widget? child, bool container = false, bool explicitChildNodes = false, bool excludeSemantics = false, bool blockUserActions = false, required SemanticsProperties properties})
-
Creates a semantic annotation using SemanticsProperties.
const
Properties
- blockUserActions → bool
-
Whether to block user interactions for the rendering subtree.
final
- child → Widget?
-
The widget below this widget in the tree.
finalinherited
- container → bool
-
If container is 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).
final
- excludeSemantics → bool
-
Whether to replace all child semantics with this node.
final
- explicitChildNodes → bool
-
Whether descendants of this widget are allowed to add semantic information
to the SemanticsNode annotated by this widget.
final
- hashCode → int
-
The hash code for this object.
no setterinherited
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- properties → SemanticsProperties
-
Contains properties used by assistive technologies to make the application
more accessible.
final
- 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 -
A render object previously associated with this widget has been removed
from the tree. The given RenderObject will be of the same type as
returned by this object's createRenderObject.
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
-
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