PlaceholderSpan class

An immutable placeholder that is embedded inline within text.

PlaceholderSpan represents a placeholder that acts as a stand-in for other content. A PlaceholderSpan by itself does not contain useful information to change a TextSpan. Instead, this class must be extended to define contents.

WidgetSpan from the widgets library extends PlaceholderSpan and may be used instead to specify a widget as the contents of the placeholder.

See also:

Inheritance
Implementers

Constructors

PlaceholderSpan({PlaceholderAlignment alignment: ui.PlaceholderAlignment.bottom, TextBaseline baseline, TextStyle style })
Creates a PlaceholderSpan with the given values. [...]
const

Properties

alignment → PlaceholderAlignment
How the placeholder aligns vertically with the text. [...]
final
baseline → TextBaseline
The TextBaseline to align against when using ui.PlaceholderAlignment.baseline, ui.PlaceholderAlignment.aboveBaseline, and ui.PlaceholderAlignment.belowBaseline. [...]
final
children → List<InlineSpan>
Returns the InlineSpan children list associated with this span if this is an instance of TextSpan, otherwise returns null.
@Deprecated('InlineSpan does not innately have children. Use TextSpan.children instead.'), read-only, inherited
hashCode → int
The hash code for this object. [...]
read-only, inherited
recognizer → GestureRecognizer
Returns the GestureRecognizer associated with this span if this is an instance of TextSpan, otherwise returns null.
@Deprecated('InlineSpan does not innately have a recognizer. Use TextSpan.recognizer instead.'), read-only, inherited
runtimeType → Type
A representation of the runtime type of the object.
read-only, inherited
style → TextStyle
The TextStyle to apply to this span. [...]
final, inherited
text → String
Returns the text associated with this span if this is an instance of TextSpan, otherwise returns null.
@Deprecated('InlineSpan does not innately have text. Use TextSpan.text instead.'), read-only, inherited

Methods

computeSemanticsInformation(List<InlineSpanSemanticsInformation> collector) → void
Walks the InlineSpan tree and accumulates a list of InlineSpanSemanticsInformation objects. [...]
override
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.
override
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node. [...]
override
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. [...]
override
visitTextSpan(bool visitor(TextSpan span)) → bool
The visitTextSpan method is invalid on PlaceholderSpans
@Deprecated('Use to visitChildren instead'), override
build(ParagraphBuilder builder, { double textScaleFactor: 1.0, List<PlaceholderDimensions> dimensions }) → void
Apply the properties of this object to the given ParagraphBuilder, from which a Paragraph can be obtained. [...]
inherited
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. [...]
@protected, inherited
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. [...]
inherited
debugAssertIsValid() → bool
In checked mode, throws an exception if the object is not in a valid configuration. Otherwise, returns true. [...]
inherited
debugDescribeChildren() → List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children. [...]
@protected, inherited
getSemanticsInformation() → List<InlineSpanSemanticsInformation>
Flattens the InlineSpan tree to a list of InlineSpanSemanticsInformation objects. [...]
inherited
getSpanForPosition(TextPosition position) → InlineSpan
Returns the InlineSpan that contains the given position in the text.
inherited
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. [...]
@protected, inherited
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.debug }) → String
Returns 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
Walks this InlineSpan and any descendants in pre-order and calls visitor for each span that has content. [...]
inherited

Operators

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