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
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
tags ↔ Set<SemanticsTag>?
The SemanticsTags 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.
mustCallSuper">@mustCallSuperprotected">@protectedinherited
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.
mustCallSuper">@mustCallSuperprotected">@protectedinherited
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 the childrenInInversePaintOrder argument.
visitChildren(SemanticsNodeVisitor visitor) → void
Visits the immediate children of this node.

Operators

operator ==(Object other) → bool
The equality operator.
inherited