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

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
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