blob: 3dc8e99f8647b632ba7d60a8dbefd3ab36702aac [file] [log] [blame]
// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';
import 'color_scheme.dart';
import 'colors.dart';
import 'expansion_tile_theme.dart';
import 'icons.dart';
import 'list_tile.dart';
import 'list_tile_theme.dart';
import 'material.dart';
import 'material_localizations.dart';
import 'theme.dart';
const Duration _kExpand = Duration(milliseconds: 200);
/// Enables control over a single [ExpansionTile]'s expanded/collapsed state.
///
/// It can be useful to expand or collapse an [ExpansionTile]
/// programatically, for example to reconfigure an existing expansion
/// tile based on a system event. To do so, create an [ExpansionTile]
/// with an [ExpansionTileController] that's owned by a stateful widget
/// or look up the tile's automatically created [ExpansionTileController]
/// with [ExpansionTileController.of]
///
/// The controller's [expand] and [collapse] methods cause the
/// the [ExpansionTile] to rebuild, so they may not be called from
/// a build method.
class ExpansionTileController {
/// Create a controller to be used with [ExpansionTile.controller].
ExpansionTileController();
_ExpansionTileState? _state;
/// Whether the [ExpansionTile] built with this controller is in expanded state.
///
/// This property doesn't take the animation into account. It reports `true`
/// even if the expansion animation is not completed.
///
/// See also:
///
/// * [expand], which expands the [ExpansionTile].
/// * [collapse], which collapses the [ExpansionTile].
/// * [ExpansionTile.controller] to create an ExpansionTile with a controller.
bool get isExpanded {
assert(_state != null);
return _state!._isExpanded;
}
/// Expands the [ExpansionTile] that was built with this controller;
///
/// Normally the tile is expanded automatically when the user taps on the header.
/// It is sometimes useful to trigger the expansion programmatically due
/// to external changes.
///
/// If the tile is already in the expanded state (see [isExpanded]), calling
/// this method has no effect.
///
/// Calling this method may cause the [ExpansionTile] to rebuild, so it may
/// not be called from a build method.
///
/// Calling this method will trigger an [ExpansionTile.onExpansionChanged] callback.
///
/// See also:
///
/// * [collapse], which collapses the tile.
/// * [isExpanded] to check whether the tile is expanded.
/// * [ExpansionTile.controller] to create an ExpansionTile with a controller.
void expand() {
assert(_state != null);
if (!isExpanded) {
_state!._toggleExpansion();
}
}
/// Collapses the [ExpansionTile] that was built with this controller.
///
/// Normally the tile is collapsed automatically when the user taps on the header.
/// It can be useful sometimes to trigger the collapse programmatically due
/// to some external changes.
///
/// If the tile is already in the collapsed state (see [isExpanded]), calling
/// this method has no effect.
///
/// Calling this method may cause the [ExpansionTile] to rebuild, so it may
/// not be called from a build method.
///
/// Calling this method will trigger an [ExpansionTile.onExpansionChanged] callback.
///
/// See also:
///
/// * [expand], which expands the tile.
/// * [isExpanded] to check whether the tile is expanded.
/// * [ExpansionTile.controller] to create an ExpansionTile with a controller.
void collapse() {
assert(_state != null);
if (isExpanded) {
_state!._toggleExpansion();
}
}
/// Finds the [ExpansionTileController] for the closest [ExpansionTile] instance
/// that encloses the given context.
///
/// If no [ExpansionTile] encloses the given context, calling this
/// method will cause an assert in debug mode, and throw an
/// exception in release mode.
///
/// To return null if there is no [ExpansionTile] use [maybeOf] instead.
///
/// {@tool dartpad}
/// Typical usage of the [ExpansionTileController.of] function is to call it from within the
/// `build` method of a descendant of an [ExpansionTile].
///
/// When the [ExpansionTile] is actually created in the same `build`
/// function as the callback that refers to the controller, then the
/// `context` argument to the `build` function can't be used to find
/// the [ExpansionTileController] (since it's "above" the widget
/// being returned in the widget tree). In cases like that you can
/// add a [Builder] widget, which provides a new scope with a
/// [BuildContext] that is "under" the [ExpansionTile]:
///
/// ** See code in examples/api/lib/material/expansion_tile/expansion_tile.1.dart **
/// {@end-tool}
///
/// A more efficient solution is to split your build function into
/// several widgets. This introduces a new context from which you
/// can obtain the [ExpansionTileController]. With this approach you
/// would have an outer widget that creates the [ExpansionTile]
/// populated by instances of your new inner widgets, and then in
/// these inner widgets you would use [ExpansionTileController.of].
static ExpansionTileController of(BuildContext context) {
final _ExpansionTileState? result = context.findAncestorStateOfType<_ExpansionTileState>();
if (result != null) {
return result._tileController;
}
throw FlutterError.fromParts(<DiagnosticsNode>[
ErrorSummary(
'ExpansionTileController.of() called with a context that does not contain a ExpansionTile.',
),
ErrorDescription(
'No ExpansionTile ancestor could be found starting from the context that was passed to ExpansionTileController.of(). '
'This usually happens when the context provided is from the same StatefulWidget as that '
'whose build function actually creates the ExpansionTile widget being sought.',
),
ErrorHint(
'There are several ways to avoid this problem. The simplest is to use a Builder to get a '
'context that is "under" the ExpansionTile. For an example of this, please see the '
'documentation for ExpansionTileController.of():\n'
' https://api.flutter.dev/flutter/material/ExpansionTile/of.html',
),
ErrorHint(
'A more efficient solution is to split your build function into several widgets. This '
'introduces a new context from which you can obtain the ExpansionTile. In this solution, '
'you would have an outer widget that creates the ExpansionTile populated by instances of '
'your new inner widgets, and then in these inner widgets you would use ExpansionTileController.of().\n'
'An other solution is assign a GlobalKey to the ExpansionTile, '
'then use the key.currentState property to obtain the ExpansionTile rather than '
'using the ExpansionTileController.of() function.',
),
context.describeElement('The context used was'),
]);
}
/// Finds the [ExpansionTile] from the closest instance of this class that
/// encloses the given context and returns its [ExpansionTileController].
///
/// If no [ExpansionTile] encloses the given context then return null.
/// To throw an exception instead, use [of] instead of this function.
///
/// See also:
///
/// * [of], a similar function to this one that throws if no [ExpansionTile]
/// encloses the given context. Also includes some sample code in its
/// documentation.
static ExpansionTileController? maybeOf(BuildContext context) {
return context.findAncestorStateOfType<_ExpansionTileState>()?._tileController;
}
}
/// A single-line [ListTile] with an expansion arrow icon that expands or collapses
/// the tile to reveal or hide the [children].
///
/// This widget is typically used with [ListView] to create an
/// "expand / collapse" list entry. When used with scrolling widgets like
/// [ListView], a unique [PageStorageKey] must be specified to enable the
/// [ExpansionTile] to save and restore its expanded state when it is scrolled
/// in and out of view.
///
/// This class overrides the [ListTileThemeData.iconColor] and [ListTileThemeData.textColor]
/// theme properties for its [ListTile]. These colors animate between values when
/// the tile is expanded and collapsed: between [iconColor], [collapsedIconColor] and
/// between [textColor] and [collapsedTextColor].
///
/// The expansion arrow icon is shown on the right by default in left-to-right languages
/// (i.e. the trailing edge). This can be changed using [controlAffinity]. This maps
/// to the [leading] and [trailing] properties of [ExpansionTile].
///
/// {@tool dartpad}
/// This example demonstrates how the [ExpansionTile] icon's location and appearance
/// can be customized.
///
/// ** See code in examples/api/lib/material/expansion_tile/expansion_tile.0.dart **
/// {@end-tool}
///
/// {@tool dartpad}
/// This example demonstrates how an [ExpansionTileController] can be used to
/// programatically expand or collapse an [ExpansionTile].
///
/// ** See code in examples/api/lib/material/expansion_tile/expansion_tile.1.dart **
/// {@end-tool}
///
/// See also:
///
/// * [ListTile], useful for creating expansion tile [children] when the
/// expansion tile represents a sublist.
/// * The "Expand and collapse" section of
/// <https://material.io/components/lists#types>
class ExpansionTile extends StatefulWidget {
/// Creates a single-line [ListTile] with an expansion arrow icon that expands or collapses
/// the tile to reveal or hide the [children]. The [initiallyExpanded] property must
/// be non-null.
const ExpansionTile({
super.key,
this.leading,
required this.title,
this.subtitle,
this.onExpansionChanged,
this.children = const <Widget>[],
this.trailing,
this.initiallyExpanded = false,
this.maintainState = false,
this.tilePadding,
this.expandedCrossAxisAlignment,
this.expandedAlignment,
this.childrenPadding,
this.backgroundColor,
this.collapsedBackgroundColor,
this.textColor,
this.collapsedTextColor,
this.iconColor,
this.collapsedIconColor,
this.shape,
this.collapsedShape,
this.clipBehavior,
this.controlAffinity,
this.controller,
}) : assert(
expandedCrossAxisAlignment != CrossAxisAlignment.baseline,
'CrossAxisAlignment.baseline is not supported since the expanded children '
'are aligned in a column, not a row. Try to use another constant.',
);
/// A widget to display before the title.
///
/// Typically a [CircleAvatar] widget.
///
/// Depending on the value of [controlAffinity], the [leading] widget
/// may replace the rotating expansion arrow icon.
final Widget? leading;
/// The primary content of the list item.
///
/// Typically a [Text] widget.
final Widget title;
/// Additional content displayed below the title.
///
/// Typically a [Text] widget.
final Widget? subtitle;
/// Called when the tile expands or collapses.
///
/// When the tile starts expanding, this function is called with the value
/// true. When the tile starts collapsing, this function is called with
/// the value false.
final ValueChanged<bool>? onExpansionChanged;
/// The widgets that are displayed when the tile expands.
///
/// Typically [ListTile] widgets.
final List<Widget> children;
/// The color to display behind the sublist when expanded.
///
/// If this property is null then [ExpansionTileThemeData.backgroundColor] is used. If that
/// is also null then Colors.transparent is used.
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final Color? backgroundColor;
/// When not null, defines the background color of tile when the sublist is collapsed.
///
/// If this property is null then [ExpansionTileThemeData.collapsedBackgroundColor] is used.
/// If that is also null then Colors.transparent is used.
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final Color? collapsedBackgroundColor;
/// A widget to display after the title.
///
/// Depending on the value of [controlAffinity], the [trailing] widget
/// may replace the rotating expansion arrow icon.
final Widget? trailing;
/// Specifies if the list tile is initially expanded (true) or collapsed (false, the default).
final bool initiallyExpanded;
/// Specifies whether the state of the children is maintained when the tile expands and collapses.
///
/// When true, the children are kept in the tree while the tile is collapsed.
/// When false (default), the children are removed from the tree when the tile is
/// collapsed and recreated upon expansion.
final bool maintainState;
/// Specifies padding for the [ListTile].
///
/// Analogous to [ListTile.contentPadding], this property defines the insets for
/// the [leading], [title], [subtitle] and [trailing] widgets. It does not inset
/// the expanded [children] widgets.
///
/// If this property is null then [ExpansionTileThemeData.tilePadding] is used. If that
/// is also null then the tile's padding is `EdgeInsets.symmetric(horizontal: 16.0)`.
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final EdgeInsetsGeometry? tilePadding;
/// Specifies the alignment of [children], which are arranged in a column when
/// the tile is expanded.
///
/// The internals of the expanded tile make use of a [Column] widget for
/// [children], and [Align] widget to align the column. The [expandedAlignment]
/// parameter is passed directly into the [Align].
///
/// Modifying this property controls the alignment of the column within the
/// expanded tile, not the alignment of [children] widgets within the column.
/// To align each child within [children], see [expandedCrossAxisAlignment].
///
/// The width of the column is the width of the widest child widget in [children].
///
/// If this property is null then [ExpansionTileThemeData.expandedAlignment]is used. If that
/// is also null then the value of [expandedAlignment] is [Alignment.center].
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final Alignment? expandedAlignment;
/// Specifies the alignment of each child within [children] when the tile is expanded.
///
/// The internals of the expanded tile make use of a [Column] widget for
/// [children], and the `crossAxisAlignment` parameter is passed directly into
/// the [Column].
///
/// Modifying this property controls the cross axis alignment of each child
/// within its [Column]. The width of the [Column] that houses [children] will
/// be the same as the widest child widget in [children]. The width of the
/// [Column] might not be equal to the width of the expanded tile.
///
/// To align the [Column] along the expanded tile, use the [expandedAlignment]
/// property instead.
///
/// When the value is null, the value of [expandedCrossAxisAlignment] is
/// [CrossAxisAlignment.center].
final CrossAxisAlignment? expandedCrossAxisAlignment;
/// Specifies padding for [children].
///
/// If this property is null then [ExpansionTileThemeData.childrenPadding] is used. If that
/// is also null then the value of [childrenPadding] is [EdgeInsets.zero].
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final EdgeInsetsGeometry? childrenPadding;
/// The icon color of tile's expansion arrow icon when the sublist is expanded.
///
/// Used to override to the [ListTileThemeData.iconColor].
///
/// If this property is null then [ExpansionTileThemeData.iconColor] is used. If that
/// is also null then the value of [ColorScheme.primary] is used.
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final Color? iconColor;
/// The icon color of tile's expansion arrow icon when the sublist is collapsed.
///
/// Used to override to the [ListTileThemeData.iconColor].
///
/// If this property is null then [ExpansionTileThemeData.collapsedIconColor] is used. If that
/// is also null and [ThemeData.useMaterial3] is true, [ColorScheme.onSurface] is used. Otherwise,
/// defaults to [ThemeData.unselectedWidgetColor] color.
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final Color? collapsedIconColor;
/// The color of the tile's titles when the sublist is expanded.
///
/// Used to override to the [ListTileThemeData.textColor].
///
/// If this property is null then [ExpansionTileThemeData.textColor] is used. If that
/// is also null then and [ThemeData.useMaterial3] is true, color of the [TextTheme.bodyLarge]
/// will be used for the [title] and [subtitle]. Otherwise, defaults to [ColorScheme.primary] color.
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final Color? textColor;
/// The color of the tile's titles when the sublist is collapsed.
///
/// Used to override to the [ListTileThemeData.textColor].
///
/// If this property is null then [ExpansionTileThemeData.collapsedTextColor] is used.
/// If that is also null and [ThemeData.useMaterial3] is true, color of the
/// [TextTheme.bodyLarge] will be used for the [title] and [subtitle]. Otherwise,
/// defaults to color of the [TextTheme.titleMedium].
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final Color? collapsedTextColor;
/// The tile's border shape when the sublist is expanded.
///
/// If this property is null, the [ExpansionTileThemeData.shape] is used. If that
/// is also null, a [Border] with vertical sides default to [ThemeData.dividerColor] is used
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final ShapeBorder? shape;
/// The tile's border shape when the sublist is collapsed.
///
/// If this property is null, the [ExpansionTileThemeData.collapsedShape] is used. If that
/// is also null, a [Border] with vertical sides default to Color [Colors.transparent] is used
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final ShapeBorder? collapsedShape;
/// {@macro flutter.material.Material.clipBehavior}
///
/// If this property is null, the [ExpansionTileThemeData.clipBehavior] is used. If that
/// is also null, a [Clip.none] is used
///
/// See also:
///
/// * [ExpansionTileTheme.of], which returns the nearest [ExpansionTileTheme]'s
/// [ExpansionTileThemeData].
final Clip? clipBehavior;
/// Typically used to force the expansion arrow icon to the tile's leading or trailing edge.
///
/// By default, the value of [controlAffinity] is [ListTileControlAffinity.platform],
/// which means that the expansion arrow icon will appear on the tile's trailing edge.
final ListTileControlAffinity? controlAffinity;
/// If provided, the controller can be used to expand and collapse tiles.
///
/// In cases were control over the tile's state is needed from a callback triggered
/// by a widget within the tile, [ExpansionTileController.of] may be more convenient
/// than supplying a controller.
final ExpansionTileController? controller;
@override
State<ExpansionTile> createState() => _ExpansionTileState();
}
class _ExpansionTileState extends State<ExpansionTile> with SingleTickerProviderStateMixin {
static final Animatable<double> _easeOutTween = CurveTween(curve: Curves.easeOut);
static final Animatable<double> _easeInTween = CurveTween(curve: Curves.easeIn);
static final Animatable<double> _halfTween = Tween<double>(begin: 0.0, end: 0.5);
final ShapeBorderTween _borderTween = ShapeBorderTween();
final ColorTween _headerColorTween = ColorTween();
final ColorTween _iconColorTween = ColorTween();
final ColorTween _backgroundColorTween = ColorTween();
late AnimationController _animationController;
late Animation<double> _iconTurns;
late Animation<double> _heightFactor;
late Animation<ShapeBorder?> _border;
late Animation<Color?> _headerColor;
late Animation<Color?> _iconColor;
late Animation<Color?> _backgroundColor;
bool _isExpanded = false;
late ExpansionTileController _tileController;
@override
void initState() {
super.initState();
_animationController = AnimationController(duration: _kExpand, vsync: this);
_heightFactor = _animationController.drive(_easeInTween);
_iconTurns = _animationController.drive(_halfTween.chain(_easeInTween));
_border = _animationController.drive(_borderTween.chain(_easeOutTween));
_headerColor = _animationController.drive(_headerColorTween.chain(_easeInTween));
_iconColor = _animationController.drive(_iconColorTween.chain(_easeInTween));
_backgroundColor = _animationController.drive(_backgroundColorTween.chain(_easeOutTween));
_isExpanded = PageStorage.maybeOf(context)?.readState(context) as bool? ?? widget.initiallyExpanded;
if (_isExpanded) {
_animationController.value = 1.0;
}
assert(widget.controller?._state == null);
_tileController = widget.controller ?? ExpansionTileController();
_tileController._state = this;
}
@override
void dispose() {
_tileController._state = null;
_animationController.dispose();
super.dispose();
}
void _toggleExpansion() {
final TextDirection textDirection = WidgetsLocalizations.of(context).textDirection;
final MaterialLocalizations localizations = MaterialLocalizations.of(context);
final String stateHint = _isExpanded ? localizations.expandedHint : localizations.collapsedHint;
setState(() {
_isExpanded = !_isExpanded;
if (_isExpanded) {
_animationController.forward();
} else {
_animationController.reverse().then<void>((void value) {
if (!mounted) {
return;
}
setState(() {
// Rebuild without widget.children.
});
});
}
PageStorage.maybeOf(context)?.writeState(context, _isExpanded);
});
widget.onExpansionChanged?.call(_isExpanded);
SemanticsService.announce(stateHint, textDirection);
}
void _handleTap() {
_toggleExpansion();
}
// Platform or null affinity defaults to trailing.
ListTileControlAffinity _effectiveAffinity(ListTileControlAffinity? affinity) {
switch (affinity ?? ListTileControlAffinity.trailing) {
case ListTileControlAffinity.leading:
return ListTileControlAffinity.leading;
case ListTileControlAffinity.trailing:
case ListTileControlAffinity.platform:
return ListTileControlAffinity.trailing;
}
}
Widget? _buildIcon(BuildContext context) {
return RotationTransition(
turns: _iconTurns,
child: const Icon(Icons.expand_more),
);
}
Widget? _buildLeadingIcon(BuildContext context) {
if (_effectiveAffinity(widget.controlAffinity) != ListTileControlAffinity.leading) {
return null;
}
return _buildIcon(context);
}
Widget? _buildTrailingIcon(BuildContext context) {
if (_effectiveAffinity(widget.controlAffinity) != ListTileControlAffinity.trailing) {
return null;
}
return _buildIcon(context);
}
Widget _buildChildren(BuildContext context, Widget? child) {
final ThemeData theme = Theme.of(context);
final ExpansionTileThemeData expansionTileTheme = ExpansionTileTheme.of(context);
final ShapeBorder expansionTileBorder = _border.value ?? const Border(
top: BorderSide(color: Colors.transparent),
bottom: BorderSide(color: Colors.transparent),
);
final Clip clipBehavior = widget.clipBehavior ?? expansionTileTheme.clipBehavior ?? Clip.none;
final MaterialLocalizations localizations = MaterialLocalizations.of(context);
final String onTapHint = _isExpanded
? localizations.expansionTileExpandedTapHint
: localizations.expansionTileCollapsedTapHint;
String? semanticsHint;
switch (theme.platform) {
case TargetPlatform.iOS:
case TargetPlatform.macOS:
semanticsHint = _isExpanded
? '${localizations.collapsedHint}\n ${localizations.expansionTileExpandedHint}'
: '${localizations.expandedHint}\n ${localizations.expansionTileCollapsedHint}';
case TargetPlatform.android:
case TargetPlatform.fuchsia:
case TargetPlatform.linux:
case TargetPlatform.windows:
break;
}
return Container(
clipBehavior: clipBehavior,
decoration: ShapeDecoration(
color: _backgroundColor.value ?? expansionTileTheme.backgroundColor ?? Colors.transparent,
shape: expansionTileBorder,
),
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
Semantics(
hint: semanticsHint,
onTapHint: onTapHint,
child: ListTileTheme.merge(
iconColor: _iconColor.value ?? expansionTileTheme.iconColor,
textColor: _headerColor.value,
child: ListTile(
onTap: _handleTap,
contentPadding: widget.tilePadding ?? expansionTileTheme.tilePadding,
leading: widget.leading ?? _buildLeadingIcon(context),
title: widget.title,
subtitle: widget.subtitle,
trailing: widget.trailing ?? _buildTrailingIcon(context),
),
),
),
ClipRect(
child: Align(
alignment: widget.expandedAlignment
?? expansionTileTheme.expandedAlignment
?? Alignment.center,
heightFactor: _heightFactor.value,
child: child,
),
),
],
),
);
}
@override
void didChangeDependencies() {
final ThemeData theme = Theme.of(context);
final ExpansionTileThemeData expansionTileTheme = ExpansionTileTheme.of(context);
final ExpansionTileThemeData defaults = theme.useMaterial3
? _ExpansionTileDefaultsM3(context)
: _ExpansionTileDefaultsM2(context);
_borderTween
..begin = widget.collapsedShape
?? expansionTileTheme.collapsedShape
?? const Border(
top: BorderSide(color: Colors.transparent),
bottom: BorderSide(color: Colors.transparent),
)
..end = widget.shape
?? expansionTileTheme.shape
?? Border(
top: BorderSide(color: theme.dividerColor),
bottom: BorderSide(color: theme.dividerColor),
);
_headerColorTween
..begin = widget.collapsedTextColor
?? expansionTileTheme.collapsedTextColor
?? defaults.collapsedTextColor
..end = widget.textColor ?? expansionTileTheme.textColor ?? defaults.textColor;
_iconColorTween
..begin = widget.collapsedIconColor
?? expansionTileTheme.collapsedIconColor
?? defaults.collapsedIconColor
..end = widget.iconColor ?? expansionTileTheme.iconColor ?? defaults.iconColor;
_backgroundColorTween
..begin = widget.collapsedBackgroundColor ?? expansionTileTheme.collapsedBackgroundColor
..end = widget.backgroundColor ?? expansionTileTheme.backgroundColor;
super.didChangeDependencies();
}
@override
Widget build(BuildContext context) {
final ExpansionTileThemeData expansionTileTheme = ExpansionTileTheme.of(context);
final bool closed = !_isExpanded && _animationController.isDismissed;
final bool shouldRemoveChildren = closed && !widget.maintainState;
final Widget result = Offstage(
offstage: closed,
child: TickerMode(
enabled: !closed,
child: Padding(
padding: widget.childrenPadding ?? expansionTileTheme.childrenPadding ?? EdgeInsets.zero,
child: Column(
crossAxisAlignment: widget.expandedCrossAxisAlignment ?? CrossAxisAlignment.center,
children: widget.children,
),
),
),
);
return AnimatedBuilder(
animation: _animationController.view,
builder: _buildChildren,
child: shouldRemoveChildren ? null : result,
);
}
}
class _ExpansionTileDefaultsM2 extends ExpansionTileThemeData {
_ExpansionTileDefaultsM2(this.context);
final BuildContext context;
late final ThemeData _theme = Theme.of(context);
late final ColorScheme _colorScheme = _theme.colorScheme;
@override
Color? get textColor => _colorScheme.primary;
@override
Color? get iconColor => _colorScheme.primary;
@override
Color? get collapsedTextColor => _theme.textTheme.titleMedium!.color;
@override
Color? get collapsedIconColor => _theme.unselectedWidgetColor;
}
// BEGIN GENERATED TOKEN PROPERTIES - ExpansionTile
// Do not edit by hand. The code between the "BEGIN GENERATED" and
// "END GENERATED" comments are generated from data in the Material
// Design token database by the script:
// dev/tools/gen_defaults/bin/gen_defaults.dart.
class _ExpansionTileDefaultsM3 extends ExpansionTileThemeData {
_ExpansionTileDefaultsM3(this.context);
final BuildContext context;
late final ThemeData _theme = Theme.of(context);
late final ColorScheme _colors = _theme.colorScheme;
@override
Color? get textColor => _colors.onSurface;
@override
Color? get iconColor => _colors.primary;
@override
Color? get collapsedTextColor => _colors.onSurface;
@override
Color? get collapsedIconColor => _colors.onSurfaceVariant;
}
// END GENERATED TOKEN PROPERTIES - ExpansionTile