SemanticsTreeWalker class

Walks the live SemanticsNode tree and captures a flat, depth-first snapshot of it as A11ySemanticsNodeInfo.

Unlike ElementTreeWalker, which reads the Element/Widget configuration tree, this reads the tree the engine actually compiles for assistive technology — the same data a screen reader would announce. That's necessary for rules (SemanticLabelRule, FocusOrderRule) to catch widgets that contribute semantics via a custom RenderObject rather than an explicit Semantics widget.

The engine only computes this tree while something is listening for it. Callers must hold an active SemanticsHandle — e.g. via SemanticsBinding.ensureSemantics — for the duration walk is called; A11yLensOverlay manages this automatically. Without one, walk returns an empty list rather than throwing.

Constructors

SemanticsTreeWalker()

const

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

walk(BuildContext context) → List<A11ySemanticsNodeInfo>

Returns a flattened, depth-first snapshot of the semantics subtree below context — mirroring ElementTreeWalker.walk's scoping, so a BuildContext passed to one behaves the same way passed to the other (e.g. via A11yReport.generate's or expectNoA11yViolations's finder).

Operators

operator ==(Object other) → bool

The equality operator.

inherited