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

• Object
• DiagnosticableTree
• Widget
• StatefulWidget
• Expander

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 setter, inherited

isExpanded → ValueNotifier<bool>

Controls the expansion state of the widget.

final

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

onExpansionChanged → ValueChanged<bool>

Called when the expansion state changes.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

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