Expander class

A component that creates a collapsible container with a clickable header.

Expander is useful for creating accordion-style UI elements, FAQ sections, or any content that needs to be shown or hidden based on user interaction. It features smooth animations and can be controlled either through user interaction or programmatically via an ExpanderController.

See also:

• doc/component/expander.md for more detailed documentation
• ExpanderController, which can be used to control this widget
• ExpanderState, which represents this widget's state

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatefulWidget
• Expander

Mixed-in types

• BoxSignal

Available extensions

• AnimateWidgetExtensions
• DebugContainer
• IconExtension
• SkeletonExtension
• TextExtension
• WidgetExtension
• XAST
• XOnGestureWidget
• XSliverWidget
• XWidget
• XWidgetArcane
• XWidgetEdge
• XWidgetEffect
• XWidgetFrost
• XWidgetInvert
• XWidgetPixelate
• XWidgetPixelateBlur
• XWidgetRGB
• XWidgetWarp

Constructors

Expander.new({Key? key, required Widget child, required Widget header, double gapPadding = 8, CrossAxisAlignment crossAxisAlignment = CrossAxisAlignment.start, bool initiallyExpanded = false, ExpanderController? controller, Duration duration = const Duration(milliseconds: 250), Duration reverseDuration = const Duration(milliseconds: 250), Curve curve = Curves.easeOutCirc, AlignmentGeometry alignment = Alignment.topCenter, Widget? overrideSeparator})

Creates an Expander widget.

const

Properties

alignment → AlignmentGeometry

Alignment of the animated content.

final

asBuilder → NeverWidgetBuilder

Available on Widget, provided by the WidgetExtension extension

no setter

asSliver → Widget

Available on Widget, provided by the XWidgetArcane extension

no setter

ast → Widget

Available on Widget, provided by the XAST extension

no setter

base → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

black → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

blockQuote → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

blurIn → Widget

Available on Widget, provided by the XWidgetEffect extension

no setter

bold → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

centered → Widget

Available on Widget, provided by the XWidget extension

no setter

child → Widget

The content to show when expanded.

final

controller → ExpanderController?

Optional controller for external state management.

final

crossAxisAlignment → CrossAxisAlignment

Cross-axis alignment of the content.

final

curve → Curve

Animation curve for expansion.

final

duration → Duration

Duration of the expansion animation.

final

ellipsis → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

expand → Widget

Available on Widget, provided by the XWidget extension

no setter

extraBold → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

extraLight → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

firstP → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

flexible → Widget

Available on Widget, provided by the XWidget extension

no setter

foreground → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

gapPadding → double

Space between header and expanded content.

final

h1 → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

h2 → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

h3 → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

h4 → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

hashCode → int

The hash code for this object.

no setter, inherited

header → Widget

The always-visible header that toggles expansion when clicked.

final

ih → Widget

Available on Widget, provided by the XWidgetArcane extension

no setter

initiallyExpanded → bool

Whether the content is initially expanded.

final

inlineCode → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

intrinsicHeight → Widget

Available on Widget, provided by the XWidget extension

no setter

intrinsicSize → Widget

Available on Widget, provided by the XWidget extension

no setter

intrinsicWidth → Widget

Available on Widget, provided by the XWidget extension

no setter

italic → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

iw → Widget

Available on Widget, provided by the XWidgetArcane extension

no setter

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

large → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

lead → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

li → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

light → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

medium → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

modify → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

mono → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

muted → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

normal → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

overrideSeparator → Widget?

Custom widget to show between header and content instead of gap.

final

p → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

primaryForeground → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

reverseDuration → Duration

Duration of the collapse animation.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

safeArea → Widget

Available on Widget, provided by the XWidget extension

no setter

sans → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

scrollable → Widget

Available on Widget, provided by the XWidget extension

no setter

scrollableHorizontal → Widget

Available on Widget, provided by the XWidget extension

no setter

secondaryForeground → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

semiBold → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

singleLine → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

small → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

textCenter → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

textEnd → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

textJustify → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

textLarge → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

textLeft → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

textMuted → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

textRight → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

textSmall → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

textStart → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

thin → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

underline → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

x2Large → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

x3Large → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

x4Large → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

x5Large → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

x6Large → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

x7Large → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

x8Large → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

x9Large → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

xLarge → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

xSmall → TextModifier

Available on Widget, provided by the TextExtension extension

no setter

Methods

animate({Key? key, List<Effect>? effects, AnimateCallback? onInit, AnimateCallback? onPlay, AnimateCallback? onComplete, bool? autoPlay, Duration? delay, AnimationController? controller, Adapter? adapter, double? target, double? value}) → Animate

Available on Widget, provided by the AnimateWidgetExtensions extension

Wraps the target Widget in an Animate instance, and returns the instance for chaining calls. Ex. myWidget.animate() is equivalent to Animate(child: myWidget).

asSkeleton({bool enabled = true, bool leaf = false, Widget? replacement, bool unite = false, AsyncSnapshot? snapshot}) → Widget

Available on Widget, provided by the SkeletonExtension extension

asSkeletonSliver({bool enabled = true}) → Widget

Available on Widget, provided by the SkeletonExtension extension

center({Key? key}) → Widget

Available on Widget, provided by the WidgetExtension extension

clip({Clip clipBehavior = Clip.hardEdge}) → Widget

Available on Widget, provided by the WidgetExtension extension

clipOval({Clip clipBehavior = Clip.antiAlias}) → Widget

Available on Widget, provided by the WidgetExtension extension

clipPath({Clip clipBehavior = Clip.antiAlias, required CustomClipper<Path> clipper}) → Widget

Available on Widget, provided by the WidgetExtension extension

clipRRect({BorderRadiusGeometry borderRadius = BorderRadius.zero, Clip clipBehavior = Clip.antiAlias}) → Widget

Available on Widget, provided by the WidgetExtension extension

constrained({double? minWidth, double? maxWidth, double? minHeight, double? maxHeight, double? width, double? height}) → Widget

Available on Widget, provided by the WidgetExtension extension

createElement() → StatefulElement

Creates a StatefulElement to manage this widget's location in the tree.

inherited

createState() → State<Expander>

Creates the mutable state for this widget at a given location in the tree.

override

debugContainer([Color color = Colors.red]) → Widget

Available on Widget, provided by the DebugContainer extension

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

excludeSkeleton({bool exclude = true}) → Widget

Available on Widget, provided by the SkeletonExtension extension

expanded({int flex = 1}) → Widget

Available on Widget, provided by the WidgetExtension extension

iconDestructiveForeground() → Widget

Available on Widget, provided by the IconExtension extension

iconLarge() → Widget

Available on Widget, provided by the IconExtension extension

iconMedium() → Widget

Available on Widget, provided by the IconExtension extension

iconMutedForeground() → Widget

Available on Widget, provided by the IconExtension extension

iconPrimary() → Widget

Available on Widget, provided by the IconExtension extension

iconPrimaryForeground() → Widget

Available on Widget, provided by the IconExtension extension

iconSecondary() → Widget

Available on Widget, provided by the IconExtension extension

iconSecondaryForeground() → Widget

Available on Widget, provided by the IconExtension extension

iconSmall() → Widget

Available on Widget, provided by the IconExtension extension

iconX2Large() → Widget

Available on Widget, provided by the IconExtension extension

iconX2Small() → Widget

Available on Widget, provided by the IconExtension extension

iconX3Large() → Widget

Available on Widget, provided by the IconExtension extension

iconX3Small() → Widget

Available on Widget, provided by the IconExtension extension

iconX4Large() → Widget

Available on Widget, provided by the IconExtension extension

iconX4Small() → Widget

Available on Widget, provided by the IconExtension extension

iconXLarge() → Widget

Available on Widget, provided by the IconExtension extension

iconXSmall() → Widget

Available on Widget, provided by the IconExtension extension

ignoreSkeleton() → Widget

Available on Widget, provided by the SkeletonExtension extension

intrinsic({double? stepWidth, double? stepHeight}) → Widget

Available on Widget, provided by the WidgetExtension extension

intrinsicHeight() → Widget

Available on Widget, provided by the WidgetExtension extension

intrinsicWidth({double? stepWidth, double? stepHeight}) → Widget

Available on Widget, provided by the WidgetExtension extension

isSliver(BuildContext context) → bool

Available on Widget, provided by the XSliverWidget extension

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

onDoublePressed(VoidCallback action, {HitTestBehavior? behavior, Set<PointerDeviceKind>? supportedDevices}) → Widget

Available on Widget, provided by the XOnGestureWidget extension

Adds a handler for double press/tap gestures.

onHover(void action(bool hovering)) → Widget

Available on Widget, provided by the XOnGestureWidget extension

Adds a handler for hover events.

onLongPressed(VoidCallback action, {HitTestBehavior? behavior, Set<PointerDeviceKind>? supportedDevices}) → Widget

Available on Widget, provided by the XOnGestureWidget extension

Adds a handler for long press gestures with the primary button.

onLongSecondaryPressed(VoidCallback action, {HitTestBehavior? behavior, Set<PointerDeviceKind>? supportedDevices}) → Widget

Available on Widget, provided by the XOnGestureWidget extension

Adds a handler for long press gestures with the secondary button.

onLongTertiaryPressed(VoidCallback action, {HitTestBehavior? behavior, Set<PointerDeviceKind>? supportedDevices}) → Widget

Available on Widget, provided by the XOnGestureWidget extension

Adds a handler for long press gestures with the tertiary button.

onPressed(VoidCallback action, {HitTestBehavior? behavior, Set<PointerDeviceKind>? supportedDevices}) → Widget

Available on Widget, provided by the XOnGestureWidget extension

Adds a handler for primary press/tap gestures (equivalent to onTap).

onSecondaryPressed(VoidCallback action, {HitTestBehavior? behavior, Set<PointerDeviceKind>? supportedDevices}) → Widget

Available on Widget, provided by the XOnGestureWidget extension

Adds a handler for secondary press gestures (equivalent to right-click).

onTertiaryPressed(VoidCallback action, {HitTestBehavior? behavior, Set<PointerDeviceKind>? supportedDevices}) → Widget

Available on Widget, provided by the XOnGestureWidget extension

Adds a handler for tertiary press gestures (equivalent to middle-click).

pad(double all) → Widget

Available on Widget, provided by the XWidget extension

padBottom(double value) → Widget

Available on Widget, provided by the XWidget extension

padLeft(double value) → Widget

Available on Widget, provided by the XWidget extension

padOnly({double left = 0, double top = 0, double right = 0, double bottom = 0}) → Widget

Available on Widget, provided by the XWidget extension

padRight(double value) → Widget

Available on Widget, provided by the XWidget extension

padTop(double value) → Widget

Available on Widget, provided by the XWidget extension

positioned({Key? key, double? left, double? top, double? right, double? bottom}) → Widget

Available on Widget, provided by the WidgetExtension extension

shadeEdge(double radius) → Widget

Available on Widget, provided by the XWidgetEdge extension

shadeFrost(double value) → Widget

Available on Widget, provided by the XWidgetFrost extension

shadeInvert() → Widget

Available on Widget, provided by the XWidgetInvert extension

shadePixelate(double radius) → Widget

Available on Widget, provided by the XWidgetPixelate extension

shadePixelateBlur({int samples = 4, double pixelSize = 8, double radius = 2}) → Widget

Available on Widget, provided by the XWidgetPixelateBlur extension

shadeRGB({double radius = 5, double spin = 1}) → Widget

Available on Widget, provided by the XWidgetRGB extension

shadeWarp({double amplitude = 1, double frequency = 1, double z = 1, int octaves = 2}) → Widget

Available on Widget, provided by the XWidgetWarp extension

shadeWarpAnimation({double amplitude = 1, double frequency = 1, double z = 1, double zSpeed = 1, int octaves = 2}) → Widget

Available on Widget, provided by the XWidgetWarp extension

shimmer({bool loading = true}) → Widget

Available on Widget, provided by the XWidgetArcane extension

sized({double? width, double? height}) → Widget

Available on Widget, provided by the WidgetExtension extension

sized({double? width, double? height}) → Widget

Available on Widget, provided by the XWidget extension

then(InlineSpan span) → Widget

Available on Widget, provided by the TextExtension extension

thenButton({required VoidCallback onPressed, required Widget child}) → Widget

Available on Widget, provided by the TextExtension extension

thenInlineCode(String text) → Widget

Available on Widget, provided by the TextExtension extension

thenText(String text) → Widget

Available on Widget, provided by the TextExtension extension

toBox(BuildContext context, {bool softWarn = true}) → Widget

Available on Widget, provided by the XSliverWidget extension

toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode

Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.

inherited

toSliver(BuildContext context, {bool fillRemaining = false, bool softWarn = true}) → Widget

Available on Widget, provided by the XSliverWidget extension

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

transform({Key? key, required Matrix4 transform}) → Widget

Available on Widget, provided by the WidgetExtension extension

withAlign(AlignmentGeometry alignment) → Widget

Available on Widget, provided by the WidgetExtension extension

withMargin({double? top, double? bottom, double? left, double? right, double? horizontal, double? vertical, double? all}) → Widget

Available on Widget, provided by the WidgetExtension extension

withOpacity(double opacity) → Widget

Available on Widget, provided by the WidgetExtension extension

withPadding({double? top, double? bottom, double? left, double? right, double? horizontal, double? vertical, double? all, EdgeInsetsGeometry? padding}) → Widget

Available on Widget, provided by the WidgetExtension extension

withTooltip(String tooltip) → Widget

Available on Widget, provided by the XWidgetArcane extension

Operators

operator ==(Object other) → bool

The equality operator.

inherited