Expander<T> class

An animated widget that can expand or collapse its children with smooth transitions.

Example:

Expander<String>(
  contentBuilder: (context, isExpanded, animation) {
    return Text('Content');
  },
  children: [
    Text('Child 1'),
    Text('Child 2'),
  ],
  onExpansionChanged: (expanded) {
    print('Expanded: $expanded');
  },
  isExpanded: ValueNotifier(false),
  expanderBuilder: (context, isExpanded, animation) {
    return Icon(isExpanded ? Icons.expand_more : Icons.chevron_right);
  },
)
Inheritance

Constructors

Expander({required ExpanderBuilder contentBuilder, required List<Widget> children, required ValueChanged<bool> onExpansionChanged, required ValueNotifier<bool> isExpanded, required ExpanderBuilder expanderBuilder, bool canExpand = true, Key? key, Curve animationCurve = Curves.easeInOut, Duration animationDuration = const Duration(milliseconds: 500)})
Creates an expander widget with the specified parameters.
const

Properties

animationCurve → Curve
The animation curve for expand/collapse transitions.
final
animationDuration → Duration
The duration of expand/collapse animations.
final
canExpand → bool
Whether this widget can be expanded (shows an expander icon).
final
children → List<Widget>
The widgets to show when the expander is expanded.
final
contentBuilder → ExpanderBuilder
Builds the main content of the expander.
final
expanderBuilder → ExpanderBuilder
Builds the expander icon (typically an arrow or chevron).
final
hashCode → int
The hash code for this object.
no setterinherited
isExpanded → ValueNotifier<bool>
Controls the expansion state of the widget.
final
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
onExpansionChanged → ValueChanged<bool>
Called when the expansion state changes.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<Expander<T>>
Creates the mutable state for this widget at a given location in the tree.
override
debugDescribeChildren() → List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent 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
toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String
A string representation of this object.
inherited
toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug, int wrapWidth = 65}) → 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 short, textual description of this widget.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited