semantics library Null safety
The Flutter semantics package.
To use, import package:flutter/semantics.dart.
The SemanticsEvent classes define the protocol for sending semantic events to the platform.
The SemanticsNode hierarchy represents the semantic structure of the UI and is used by the platform-specific accessibility services.
Classes
- AccessibilityFeatures
- Additional accessibility features that may be enabled by the platform.
- AnnounceSemanticsEvent
- An event for a semantic announcement.
- AttributedString
- A string that carries a list of StringAttributes.
- AttributedStringProperty
- A DiagnosticsProperty for AttributedStrings, which shows a string when there are no attributes, and more details otherwise.
- CustomSemanticsAction
- An identifier of a custom semantics action.
- DiagnosticPropertiesBuilder
- Builder to accumulate properties and configuration used to assemble a DiagnosticsNode from a Diagnosticable object.
- DiagnosticsNode
- Defines diagnostics data for a value.
- Key
- A Key is an identifier for Widgets, Elements and SemanticsNodes.
- LocaleStringAttribute
- A string attribute that causes the assistive technologies, e.g. VoiceOver, to treat string as a certain language.
- LongPressSemanticsEvent
- An event which triggers long press semantic feedback.
- Matrix4
- 4D Matrix. Values are stored in column major order.
- Offset
- An immutable 2D floating-point offset.
- OrdinalSortKey
-
A SemanticsSortKey that sorts simply based on the
doublevalue it is given. - Rect
- An immutable, 2D, axis-aligned, floating-point rectangle whose coordinates are relative to a given origin.
- SemanticsAction
- The possible actions that can be conveyed from the operating system accessibility APIs to a semantics node.
- SemanticsConfiguration
- Describes the semantic information associated with the owning RenderObject.
- SemanticsData
- Summary information about a SemanticsNode object.
- SemanticsEvent
- An event sent by the application to notify interested listeners that something happened to the user interface (e.g. a view scrolled).
- SemanticsFlag
- A Boolean value that can be associated with a semantics node.
- SemanticsHintOverrides
- Provides hint values which override the default hints on supported platforms.
- SemanticsNode
- A node that represents some semantic data.
- SemanticsOwner
- Owns SemanticsNode objects and notifies listeners of changes to the render tree semantics.
- SemanticsProperties
- Contains properties used by assistive technologies to make the application more accessible.
- SemanticsService
- Allows access to the platform's accessibility services.
- SemanticsSortKey
- Base class for all sort keys for SemanticsProperties.sortKey accessibility traversal order sorting.
- SemanticsTag
- A tag for a SemanticsNode.
- SemanticsUpdateBuilder
- An object that creates SemanticsUpdate objects.
- SpellOutStringAttribute
- A string attribute that causes the assistive technologies, e.g. VoiceOver, to spell out the string character by character.
- StringAttribute
- An abstract interface for string attributes that affects how assistive technologies, e.g. VoiceOver or TalkBack, treat the text.
- TapSemanticEvent
- An event which triggers tap semantic feedback.
- TextSelection
- A range of text that represents a selection.
- TextTreeConfiguration
- Configuration specifying how a particular DiagnosticsTreeStyle should be rendered as text art.
- TooltipSemanticsEvent
- An event for a semantic announcement of a tooltip.
Mixins
- SemanticsBinding
- The glue between the semantics layer and the Flutter engine.
Properties
- debugSemanticsDisableAnimations ↔ bool?
-
Overrides the setting of SemanticsBinding.disableAnimations for debugging
and testing.
read / write
Functions
-
debugResetSemanticsIdCounter(
) → void - In tests use this function to reset the counter used to generate SemanticsNode.id.
Enums
- Assertiveness
- Determines the assertiveness level of the accessibility announcement.
- DebugSemanticsDumpOrder
- Used by debugDumpSemanticsTree to specify the order in which child nodes are printed.
- DiagnosticLevel
- The various priority levels used to filter which diagnostics are shown and omitted.
- DiagnosticsTreeStyle
- Styles for displaying a node in a DiagnosticsNode tree.
- TextDirection
- A direction in which text flows.
Typedefs
- MoveCursorHandler = void Function(bool extendSelection)
- Signature for SemanticsActions that move the cursor.
- SemanticsActionHandler = void Function(Object? args)
- Signature for a handler of a SemanticsAction.
- SemanticsNodeVisitor = bool Function(SemanticsNode node)
- Signature for a function that is called for each SemanticsNode.
- SetSelectionHandler = void Function(TextSelection selection)
-
Signature for the SemanticsAction.setSelection handlers to change the
text selection (or re-position the cursor) to
selection. - SetTextHandler = void Function(String text)
-
Signature for the SemanticsAction.setText handlers to replace the
current text with the input
text. - VoidCallback = void Function()
- Signature of callbacks that have no arguments and return no data.