WidgetSpan class Null safety

An immutable widget that is embedded inline within text.

The child property is the widget that will be embedded. Children are constrained by the width of the paragraph.

The child property may contain its own Widget children (if applicable), including Text and RichText widgets which may include additional WidgetSpans. Child Text and RichText widgets will be laid out independently and occupy a rectangular space in the parent text layout.

WidgetSpans will be ignored when passed into a TextPainter directly. To properly layout and paint the child widget, WidgetSpan should be passed into a Text.rich widget.

A card with Hello World! embedded inline within a TextSpan tree.

const Text.rich(
  TextSpan(
    children: <InlineSpan>[
      TextSpan(text: 'Flutter is'),
      WidgetSpan(
        child: SizedBox(
          width: 120,
          height: 50,
          child: Card(
            child: Center(
              child: Text('Hello World!')
            )
          ),
        )
      ),
      TextSpan(text: 'the best!'),
    ],
  )
)

WidgetSpan contributes the semantics of the WidgetSpan.child to the semantics tree.

Constructors

WidgetSpan({required Widget child, PlaceholderAlignment alignment = ui.PlaceholderAlignment.bottom, TextBaseline? baseline, TextStyle? style}): Creates a WidgetSpan with the given values.
const

Properties

alignment → PlaceholderAlignment: How the placeholder aligns vertically with the text.
finalinherited
baseline → TextBaseline?: The TextBaseline to align against when using ui.PlaceholderAlignment.baseline, ui.PlaceholderAlignment.aboveBaseline, and ui.PlaceholderAlignment.belowBaseline.
finalinherited
child → Widget: The widget to embed inline within text.
final
hashCode → int: The hash code for this object.
read-onlyoverride
runtimeType → Type: A representation of the runtime type of the object.
read-onlyinherited
style → TextStyle?: The TextStyle to apply to this span.
finalinherited

Methods

build(ParagraphBuilder builder, {double textScaleFactor = 1.0, List<PlaceholderDimensions>? dimensions}) → void: Adds a placeholder box to the paragraph builder if a size has been calculated for the widget.
override
codeUnitAt(int index) → int?: Returns the UTF-16 code unit at the given index in the flattened string.
inherited
codeUnitAtVisitor(int index, Accumulator offset) → int?: Performs the check at each InlineSpan for if the index falls within the range of the span and returns the corresponding code unit. Returns null otherwise.
override
compareTo(InlineSpan other) → RenderComparison: Describe the difference between this span and another, in terms of how much damage it will make to the rendering. The comparison is deep.
override
computeSemanticsInformation(List<InlineSpanSemanticsInformation> collector) → void: Walks the InlineSpan tree and accumulates a list of InlineSpanSemanticsInformation objects.
inherited
computeToPlainText(StringBuffer buffer, {bool includeSemanticsLabels = true, bool includePlaceholders = true}) → void: PlaceholderSpans are flattened to a 0xFFFC object replacement character in the plain text representation when includePlaceholders is true.
inherited
debugAssertIsValid() → bool: In debug mode, throws an exception if the object is not in a valid configuration. Otherwise, returns true.
override
debugDescribeChildren() → List<DiagnosticsNode>: Returns a list of DiagnosticsNode objects describing this node's children.
protected">@protectedinherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void: Add additional properties associated with the node.
inherited
describeSemantics(Accumulator offset, List<int> semanticsOffsets, List semanticsElements) → void: Populates the semanticsOffsets and semanticsElements with the appropriate data to be able to construct a SemanticsNode.
inherited
getSemanticsInformation() → List<InlineSpanSemanticsInformation>: Flattens the InlineSpan tree to a list of InlineSpanSemanticsInformation objects.
inherited
getSpanForPosition(TextPosition position) → InlineSpan?: Returns the text span that contains the given position in the text.
override
getSpanForPositionVisitor(TextPosition position, Accumulator offset) → InlineSpan?: Performs the check at each InlineSpan for if the position falls within the range of the span and returns the span if it does.
override
noSuchMethod(Invocation invocation) → dynamic: Invoked when a non-existent method or property is accessed.
inherited
toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode: Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.
inherited
toPlainText({bool includeSemanticsLabels = true, bool includePlaceholders = true}) → String: Flattens the InlineSpan tree into a single string.
inherited
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String: A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String: Returns a string representation of this node and its descendants.
inherited
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.
inherited
visitChildren(InlineSpanVisitor visitor) → bool: Calls visitor on this WidgetSpan. There are no children spans to walk.
override

Operators

operator ==(Object other) → bool: The equality operator.
override

Flutter
widgets
WidgetSpan class

WidgetSpan class Null safety

Constructors

Properties

Methods

Operators

widgets library