SemanticsNode class

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, SemanticsOwner owner })
Creates a semantic node to represent the root of the semantics tree. [...]

Properties

childrenCount int
The number of children this node has.
read-only
decreasedValue String
The value that value will have after a SemanticsAction.decrease action has been performed. [...]
read-only
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
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. [...]
final
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
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
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-only, override
parent SemanticsNode
The parent of this node in the tree.
read-only, override
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
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
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
attached bool
Whether this node is in a tree whose root is attached to something. [...]
read-only, inherited
depth int
The depth of this node in the tree. [...]
read-only, inherited
hashCode int
The hash code for this object. [...]
read-only, inherited
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited

Methods

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
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.
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
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
toStringShort() String
A brief description of this object, usually just the runtimeType and the hashCode. [...]
override
updateWith({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. [...]
adoptChild(covariant AbstractNode child) → void
Mark the given node as being a child of this node. [...]
@mustCallSuper, @protected, inherited
dropChild(covariant AbstractNode child) → void
Disconnect the given node from this node. [...]
@mustCallSuper, @protected, inherited
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, inherited
toString({DiagnosticLevel minLevel: DiagnosticLevel.debug }) String
Returns a string representation of this object.
inherited
toStringShallow({String joiner: ', ', DiagnosticLevel minLevel: DiagnosticLevel.debug }) String
Returns a one-line detailed description of the object. [...]
inherited

Operators

operator ==(dynamic other) bool
The equality operator. [...]
inherited