A widget that annotates the widget tree with a description of the meaning of the widgets.

Used by accessibility tools, search engines, and other semantic analysis software to determine the meaning of the application.

See also:

  • 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.semanticsAnnotator, 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 showSemanticsDebugger or MaterialApp.showSemanticsDebugger.
Inheritance

Constructors

Semantics({Key key, Widget child, bool container: false, bool checked, String label })

Creates a semantic annotation.

Properties

checked → bool

If non-null, indicates that this subtree represents a checkbox or similar widget with a "checked" state, and what its current state is.

read-only
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.

read-only
label → String

Provides a textual description of the widget.

read-only
child → Widget

The widget below this widget in the tree.

read-only, inherited
hashCode → int

Get a hash code for this object.

read-only, inherited
key → Key

Controls how one widget replaces another widget in the tree.

read-only, inherited
runtimeType → Type

A representation of the runtime type of the object.

read-only, inherited

Operators

operator ==(other) → bool

The equality operator.

inherited

Methods

createRenderObject(BuildContext context) → RenderSemanticsAnnotations

Creates an instance of the RenderObject class that this RenderObjectWidget represents, using the configuration described by this RenderObjectWidget.

debugFillDescription(List<String> description) → void

Add additional information to the given description for use by toString.

updateRenderObject(BuildContext context, 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.

createElement() → SingleChildRenderObjectElement

RenderObjectWidgets always inflate to a RenderObjectElement subclass.

inherited
didUnmountRenderObject(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 non-existent method or property is accessed.

inherited
toString() → String

Returns a string representation of this object.

inherited
toStringShort() → String

A short, textual description of this widget.

inherited