Expander class
The Expander control lets you show or hide less important content that's related to a piece of primary content that's always visible. Items contained in the Header are always visible. The user can expand and collapse the Content area, where secondary content is displayed, by interacting with the header. When the content area is expanded, it pushes other UI elements out of the way; it does not overlay other UI. The Expander can expand upwards or downwards.
Both the Header and Content areas can contain any content, from simple text to complex UI layouts. For example, you can use the control to show additional options for an item.
See also:
- Inheritance
-
- Object
- DiagnosticableTree
- Widget
- StatefulWidget
- Expander
- Available Extensions
Constructors
-
Expander({Key? key, Widget? leading, required Widget header, required Widget content, Widget? icon, Widget? trailing, Curve? animationCurve, Duration? animationDuration, ExpanderDirection direction = ExpanderDirection.down, bool initiallyExpanded = false, ValueChanged<
bool> ? onStateChanged, ButtonState<Color> ? headerBackgroundColor, ExpanderShapeBuilder? headerShape, Color? contentBackgroundColor, EdgeInsetsGeometry? contentPadding = const EdgeInsets.all(16.0), ExpanderShapeBuilder? contentShape}) -
Creates a fluent-styled expander.
const
Properties
- animationCurve → Curve?
-
The expand-collapse animation curve.
final
- animationDuration → Duration?
-
The expand-collapse animation duration.
final
- content → Widget
-
The expander content
final
- contentBackgroundColor → Color?
-
The content color of the content.
final
- contentPadding → EdgeInsetsGeometry?
-
The padding of the content.
final
- contentShape → ExpanderShapeBuilder?
-
The shape of the content
final
- direction → ExpanderDirection
-
The expand direction.
final
- hashCode → int
-
The hash code for this object.
no setterinherited
- header → Widget
-
The expander header
final
-
headerBackgroundColor
→ ButtonState<
Color> ? -
The background color of the header.
final
- headerShape → ExpanderShapeBuilder?
-
The shape of the header.
final
- icon → Widget?
-
The expander icon. If null, defaults to a chevron down or up, depending on
the direction.
final
- initiallyExpanded → bool
-
Whether the Expander is initially expanded.
final
- key → Key?
-
Controls how one widget replaces another widget in the tree.
finalinherited
- leading → Widget?
-
The leading widget.
final
-
onStateChanged
→ ValueChanged<
bool> ? -
A callback called when the current state is changed.
final
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- trailing → Widget?
-
The trailing widget. It's positioned at the right of header
and before icon.
final
Methods
-
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
-
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.
override
-
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}) → 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