SemanticsNode class Null safety
A node that represents some semantic data.
The semantics tree is maintained during the semantics phase of the pipeline (i.e., during PipelineOwner.flushSemantics), which happens after compositing. The semantics tree is then uploaded into the engine for use by assistive technology.
- Inheritance
-
- Object
- AbstractNode
- SemanticsNode
- Mixed in types
Constructors
- SemanticsNode({Key? key, VoidCallback? showOnScreen})
- Creates a semantic node.
- SemanticsNode.root({Key? key, VoidCallback? showOnScreen, required SemanticsOwner owner})
- Creates a semantic node to represent the root of the semantics tree.
Properties
- attached → bool
-
Whether this node is in a tree whose root is attached to something.
read-onlyinherited
- attributedDecreasedValue → AttributedString
-
The value in AttributedString format that value or attributedValue
will have after a SemanticsAction.decrease action has been performed.
read-only
- attributedHint → AttributedString
-
A brief description of the result of performing an action on this node
in AttributedString format.
read-only
- attributedIncreasedValue → AttributedString
-
The value in AttributedString format that value or attributedValue
will have after a SemanticsAction.increase action has been performed.
read-only
- attributedLabel → AttributedString
-
A textual description of this node in AttributedString format.
read-only
- attributedValue → AttributedString
-
A textual description for the current value of the node in
AttributedString format.
read-only
- childrenCount → int
-
The number of children this node has.
read-only
- currentValueLength → int?
-
The current number of characters that have been entered into an editable
text field.
read-only
- decreasedValue → String
-
The value that value will have after a SemanticsAction.decrease action
has been performed.
read-only
- depth → int
-
The depth of this node in the tree.
read-onlyinherited
- elevation → double
-
The elevation along the z-axis at which the rect of this SemanticsNode
is located above its parent.
read-only
- elevationAdjustment ↔ double?
-
The elevation adjustment that the parent imposes on this node.
read / write
- hasChildren → bool
-
Whether this node has a non-zero number of children.
read-only
- hashCode → int
-
The hash code for this object.
read-onlyinherited
- hint → String
-
A brief description of the result of performing an action on this node.
read-only
- hintOverrides → SemanticsHintOverrides?
-
Provides hint values which override the default hints on supported
platforms.
read-only
- id → int
-
The unique identifier for this node.
read-only
- increasedValue → String
-
The value that value will have after a SemanticsAction.increase action
has been performed.
read-only
- indexInParent ↔ int?
-
The index of this node within the parent's list of semantic children.
read / write
- isInvisible → bool
-
Whether the node is invisible.
read-only
- isMergedIntoParent ↔ bool
-
Whether this node merges its semantic information into an ancestor node.
read / write
- isMultiline → bool?
-
If this node represents a text field, this indicates whether or not it's
a multiline text field.
read-only
- isPartOfNodeMerging → bool
-
Whether this node is taking part in a merge of semantic information.
read-only
- key → Key?
-
Uniquely identifies this node in the list of sibling nodes.
final
- label → String
-
A textual description of this node.
read-only
- maxValueLength → int?
-
The maximum number of characters that can be entered into an editable
text field.
read-only
- mergeAllDescendantsIntoThisNode → bool
-
Whether this node and all of its descendants should be treated as one logical entity.
read-only
- owner → SemanticsOwner?
-
The owner for this node (null if unattached).
read-onlyoverride
- parent → SemanticsNode?
-
The parent of this node in the tree.
read-onlyoverride
- parentPaintClipRect ↔ Rect?
-
The paint clip from an ancestor that was applied to this node.
read / write
- parentSemanticsClipRect ↔ Rect?
-
The semantic clip from an ancestor that was applied to this node.
read / write
- platformViewId → int?
-
The id of the platform view, whose semantics nodes will be added as
children to this node.
read-only
- rect ↔ Rect
-
The bounding box for this node in its coordinate system.
read / write
- runtimeType → Type
-
A representation of the runtime type of the object.
read-onlyinherited
- scrollChildCount → int?
-
The total number of scrollable children that contribute to semantics.
read-only
- scrollExtentMax → double?
-
Indicates the maximum in-range value for scrollPosition if the node is
scrollable.
read-only
- scrollExtentMin → double?
-
Indicates the minimum in-range value for scrollPosition if the node is
scrollable.
read-only
- scrollIndex → int?
-
The index of the first visible semantic child of a scroll node.
read-only
- scrollPosition → double?
-
Indicates the current scrolling position in logical pixels if the node is
scrollable.
read-only
- sortKey → SemanticsSortKey?
-
Determines the position of this node among its siblings in the traversal
sort order.
read-only
-
The
SemanticsTag
s this node is tagged with.read / write - textDirection → TextDirection?
-
The reading direction for label, value, hint, increasedValue, and
decreasedValue.
read-only
- textSelection → TextSelection?
-
The currently selected text (or the position of the cursor) within value
if this node represents a text field.
read-only
- thickness → double
-
Describes how much space the SemanticsNode takes up along the z-axis.
read-only
- tooltip → String
-
A textual description of the widget's tooltip.
read-only
- transform ↔ Matrix4?
-
The transform from this node's coordinate system to its parent's coordinate system.
read / write
- value → String
-
A textual description for the current value of the node.
read-only
Methods
-
adoptChild(
covariant AbstractNode child) → void - Mark the given node as being a child of this node.
-
attach(
covariant SemanticsOwner owner) → void -
Mark this node as attached to the given owner.
override
-
debugDescribeChildren(
{DebugSemanticsDumpOrder childOrder = DebugSemanticsDumpOrder.inverseHitTest}) → List< DiagnosticsNode> -
Returns a list of
DiagnosticsNode
objects describing this node's children.override -
debugFillProperties(
DiagnosticPropertiesBuilder properties) → void -
Add additional properties associated with the node.
override
-
debugListChildrenInOrder(
DebugSemanticsDumpOrder childOrder) → List< SemanticsNode> - Returns the list of direct children of this node in the specified order.
-
detach(
) → void -
Mark this node as detached.
override
-
dropChild(
covariant AbstractNode child) → void - Disconnect the given node from this node.
-
getSemanticsData(
) → SemanticsData - Returns a summary of the semantics for this node.
-
hasFlag(
SemanticsFlag flag) → bool - Whether this node currently has a given SemanticsFlag.
-
isTagged(
SemanticsTag tag) → bool -
Whether this node is tagged with
tag
. -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a non-existent method or property is accessed.
inherited
-
redepthChild(
AbstractNode child) → void -
Adjust the depth of the given
child
to be greater than this node's own depth.protected">@protectedinherited -
redepthChildren(
) → void -
Adjust the depth of this node's children, if any.
override
-
sendEvent(
SemanticsEvent event) → void - Sends a SemanticsEvent associated with this SemanticsNode.
-
toDiagnosticsNode(
{String? name, DiagnosticsTreeStyle? style = DiagnosticsTreeStyle.sparse, DebugSemanticsDumpOrder childOrder = DebugSemanticsDumpOrder.traversalOrder}) → DiagnosticsNode -
Returns a debug representation of the object that is used by debugging
tools and by DiagnosticsNode.toStringDeep.
override
-
toString(
{DiagnosticLevel minLevel = DiagnosticLevel.info}) → String -
A string representation of this object.
inherited
-
toStringDeep(
{String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug, DebugSemanticsDumpOrder childOrder = DebugSemanticsDumpOrder.traversalOrder}) → String -
Returns a string representation of this node and its descendants.
override
-
toStringShallow(
{String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String -
Returns a one-line detailed description of the object.
inherited
-
toStringShort(
) → String -
A brief description of this object, usually just the runtimeType and the
hashCode.
override
-
updateWith(
{required SemanticsConfiguration? config, List< SemanticsNode> ? childrenInInversePaintOrder}) → void -
Reconfigures the properties of this object to describe the configuration
provided in the
config
argument and the children listed in thechildrenInInversePaintOrder
argument. -
visitChildren(
SemanticsNodeVisitor visitor) → void - Visits the immediate children of this node.
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited