MergeSemantics class
A widget that merges the semantics of its descendants.
Causes all the semantics of the subtree rooted at this node to be merged into one node in the semantics tree. For example, if you have a widget with a Text node next to a checkbox widget, this could be used to merge the label from the Text node with the "checked" semantic state of the checkbox into a single node that had both the label and the checked state. Otherwise, the label would be presented as a separate feature than the checkbox, and the user would not be able to be sure that they were related.
MergeSemantics(
child: Row(
children: <Widget>[
Checkbox(
value: true,
onChanged: (bool? value) {},
),
const Text('Settings'),
],
),
)Be aware that if two nodes in the subtree have conflicting semantics, the result may be nonsensical. For example, a subtree with a checked checkbox and an unchecked checkbox will be presented as checked. All the labels will be merged into a single string (with newlines separating each label from the other). If multiple nodes in the merged subtree can handle semantic gestures, the first one in tree order will be the one to receive the callbacks.
- Inheritance
Constructors
- MergeSemantics({Key? key, Widget? child})
-
Creates a widget that merges the semantics of its descendants.
const
Properties
- child → Widget?
-
The widget below this widget in the tree.
finalinherited
- hashCode → int
-
The hash code for this object.
no setterinherited
- 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) → RenderMergeSemantics -
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.
inherited
-
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, 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 RenderObject 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.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited