packages/flutter/lib/src/cupertino/list_section.dart - mirrors/flutter - Git at Google

 // 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/widgets.dart';

 import 'colors.dart';
 import 'theme.dart';

 // Margin on top of the list section. This was eyeballed from iOS 14.4 Simulator
 // and should be always present on top of the edge-to-edge variant.
 const double _kMarginTop = 22.0;

 // Standard header margin, determined from SwiftUI's Forms in iOS 14.2 SDK.
 const EdgeInsetsDirectional _kDefaultHeaderMargin = EdgeInsetsDirectional.fromSTEB(20.0, 0.0, 20.0, 6.0);

 // Header margin for inset grouped variant, determined from iOS 14.4 Simulator.
 const EdgeInsetsDirectional _kInsetGroupedDefaultHeaderMargin = EdgeInsetsDirectional.fromSTEB(20.0, 16.0, 20.0, 6.0);

 // Standard footer margin, determined from SwiftUI's Forms in iOS 14.2 SDK.
 const EdgeInsetsDirectional _kDefaultFooterMargin = EdgeInsetsDirectional.fromSTEB(20.0, 0.0, 20.0, 0.0);

 // Footer margin for inset grouped variant, determined from iOS 14.4 Simulator.
 const EdgeInsetsDirectional _kInsetGroupedDefaultFooterMargin = EdgeInsetsDirectional.fromSTEB(20.0, 0.0, 20.0, 10.0);

 // Margin around children in edge-to-edge variant, determined from iOS 14.4
 // Simulator.
 const EdgeInsets _kDefaultRowsMargin = EdgeInsets.only(bottom: 8.0);

 // Used for iOS "Inset Grouped" margin, determined from SwiftUI's Forms in
 // iOS 14.2 SDK.
 const EdgeInsetsDirectional _kDefaultInsetGroupedRowsMargin = EdgeInsetsDirectional.fromSTEB(20.0, 20.0, 20.0, 10.0);

 // Used for iOS "Inset Grouped" margin, determined from SwiftUI's Forms in
 // iOS 14.2 SDK.
 const EdgeInsetsDirectional _kDefaultInsetGroupedRowsMarginWithHeader = EdgeInsetsDirectional.fromSTEB(20.0, 0.0, 20.0, 10.0);

 // Used for iOS "Inset Grouped" border radius, estimated from SwiftUI's Forms in
 // iOS 14.2 SDK.
 // TODO(edrisian): This should be a rounded rectangle once that shape is added.
 const BorderRadius _kDefaultInsetGroupedBorderRadius = BorderRadius.all(Radius.circular(10.0));

 // The margin of divider used in base list section. Estimated from iOS 14.4 SDK
 // Settings app.
 const double _kBaseDividerMargin = 20.0;

 // Additional margin of divider used in base list section with list tiles with
 // leading widgets. Estimated from iOS 14.4 SDK Settings app.
 const double _kBaseAdditionalDividerMargin = 44.0;

 // The margin of divider used in inset grouped version of list section.
 // Estimated from iOS 14.4 SDK Reminders app.
 const double _kInsetDividerMargin = 14.0;

 // Additional margin of divider used in inset grouped version of list section.
 // Estimated from iOS 14.4 SDK Reminders app.
 const double _kInsetAdditionalDividerMargin = 42.0;

 // Additional margin of divider used in inset grouped version of list section
 // when there is no leading widgets. Estimated from iOS 14.4 SDK Notes app.
 const double _kInsetAdditionalDividerMarginWithoutLeading = 14.0;

 // Color of header and footer text in edge-to-edge variant.
 const Color _kHeaderFooterColor = CupertinoDynamicColor(
   color: Color.fromRGBO(108, 108, 108, 1.0),
   darkColor: Color.fromRGBO(142, 142, 146, 1.0),
   highContrastColor: Color.fromRGBO(74, 74, 77, 1.0),
   darkHighContrastColor: Color.fromRGBO(176, 176, 183, 1.0),
   elevatedColor: Color.fromRGBO(108, 108, 108, 1.0),
   darkElevatedColor: Color.fromRGBO(142, 142, 146, 1.0),
   highContrastElevatedColor: Color.fromRGBO(108, 108, 108, 1.0),
   darkHighContrastElevatedColor: Color.fromRGBO(142, 142, 146, 1.0),
 );

 /// Denotes what type of the list section a [CupertinoListSection] is.
 ///
 /// This is for internal use only.
 enum CupertinoListSectionType {
   /// A basic form of [CupertinoListSection].
   base,

   /// An inset-grouped style of [CupertinoListSection].
   insetGrouped,
 }

 /// An iOS-style list section.
 ///
 /// The [CupertinoListSection] is a container for children widgets. These are
 /// most often [CupertinoListTile]s.
 ///
 /// The base constructor for [CupertinoListSection] constructs an
 /// edge-to-edge style section which includes an iOS-style header, the dividers
 /// between rows, and borders on top and bottom of the rows. An example of such
 /// list section are sections in iOS Settings app.
 ///
 /// The [CupertinoListSection.insetGrouped] constructor creates a round-edged
 /// and padded section that is seen in iOS Notes and Reminders apps. It creates
 /// an iOS-style header, and the dividers between rows. Does not create borders
 /// on top and bottom of the rows.
 ///
 /// The section [header] lies above the [children] rows, with margins and style
 /// that match the iOS style.
 ///
 /// The section [footer] lies below the [children] rows and is used to provide
 /// additional information for current list section.
 ///
 /// The [children] is the list of widgets to be displayed in this list section.
 /// Typically, the children are of type [CupertinoListTile], however these is
 /// not enforced.
 ///
 /// The [margin] is used to provide spacing around the content area of the
 /// section encapsulating [children].
 ///
 /// The [decoration] of [children] specifies how they should be decorated. If it
 /// is not provided in constructor, the background color of [children] defaults
 /// to [CupertinoColors.secondarySystemGroupedBackground] and border radius of
 /// children group defaults to 10.0 circular radius when constructing with
 /// [CupertinoListSection.insetGrouped]. Defaults to zero radius for the
 /// standard [CupertinoListSection] constructor.
 ///
 /// The [dividerMargin] and [additionalDividerMargin] specify the starting
 /// margin of the divider between list tiles. The [dividerMargin] is always
 /// present, but [additionalDividerMargin] is only added to the [dividerMargin]
 /// if `hasLeading` is set to true in the constructor, which is the default
 /// value.
 ///
 /// The [backgroundColor] of the section defaults to
 /// [CupertinoColors.systemGroupedBackground].
 ///
 /// {@macro flutter.material.Material.clipBehavior}
 ///
 /// {@tool dartpad}
 /// Creates a base [CupertinoListSection] containing [CupertinoListTile]s with
 /// `leading`, `title`, `additionalInfo` and `trailing` widgets.
 ///
 /// ** See code in examples/api/lib/cupertino/list_section/list_section_base.0.dart **
 /// {@end-tool}
 ///
 /// {@tool dartpad}
 /// Creates an "Inset Grouped" [CupertinoListSection] containing
 /// notched [CupertinoListTile]s with `leading`, `title`, `additionalInfo` and
 /// `trailing` widgets.
 ///
 /// ** See code in examples/api/lib/cupertino/list_section/list_section_inset.0.dart **
 /// {@end-tool}
 ///
 /// See also:
 ///
 ///  * [CupertinoListTile], an iOS-style list tile, a typical child of
 ///    [CupertinoListSection].
 ///  * [CupertinoFormSection], an iOS-style form section.
 class CupertinoListSection extends StatelessWidget {
   /// Creates a section that mimics standard iOS forms.
   ///
   /// The base constructor for [CupertinoListSection] constructs an
   /// edge-to-edge style section which includes an iOS-style header, the dividers
   /// between rows, and borders on top and bottom of the rows. An example of such
   /// list section are sections in iOS Settings app.
   ///
   /// The [header] parameter sets the form section header. The section header
   /// lies above the [children] rows, with margins that match the iOS style.
   ///
   /// The [footer] parameter sets the form section footer. The section footer
   /// lies below the [children] rows.
   ///
   /// The [children] parameter is required and sets the list of rows shown in
   /// the section. The [children] parameter takes a list, as opposed to a more
   /// efficient builder function that lazy builds, because forms are intended to
   /// be short in row count. It is recommended that only [CupertinoFormRow] and
   /// [CupertinoTextFormFieldRow] widgets be included in the [children] list in
   /// order to retain the iOS look.
   ///
   /// The [margin] parameter sets the spacing around the content area of the
   /// section encapsulating [children], and defaults to zero padding.
   ///
   /// The [decoration] parameter sets the decoration around [children].
   /// If null, defaults to [CupertinoColors.secondarySystemGroupedBackground].
   /// If null, defaults to 10.0 circular radius when constructing with
   /// [CupertinoListSection.insetGrouped]. Defaults to zero radius for the
   /// standard [CupertinoListSection] constructor.
   ///
   /// The [backgroundColor] parameter sets the background color behind the
   /// section. If null, defaults to [CupertinoColors.systemGroupedBackground].
   ///
   /// The [dividerMargin] parameter sets the starting offset of the divider
   /// between rows.
   ///
   /// The [additionalDividerMargin] parameter adds additional margin to existing
   /// [dividerMargin] when [hasLeading] is set to true. By default, it offsets
   /// for the width of leading and space between leading and title of
   /// [CupertinoListTile], but it can be overwritten for custom look.
   ///
   /// The [hasLeading] parameter specifies whether children [CupertinoListTile]
   /// widgets contain leading or not. Used for calculating correct starting
   /// margin for the divider between rows.
   ///
   /// The [topMargin] is used to specify the margin above the list section. It
   /// matches the iOS look by default.
   ///
   /// {@macro flutter.material.Material.clipBehavior}
   const CupertinoListSection({
     super.key,
     this.children,
     this.header,
     this.footer,
     this.margin = _kDefaultRowsMargin,
     this.backgroundColor = CupertinoColors.systemGroupedBackground,
     this.decoration,
     this.clipBehavior = Clip.none,
     this.dividerMargin = _kBaseDividerMargin,
     double? additionalDividerMargin,
     this.topMargin = _kMarginTop,
     bool hasLeading = true,
   }) : assert((children != null && children.length > 0) || header != null),
        type = CupertinoListSectionType.base,
        additionalDividerMargin = additionalDividerMargin ??
            (hasLeading ? _kBaseAdditionalDividerMargin : 0.0);

   /// Creates a section that mimics standard "Inset Grouped" iOS list section.
   ///
   /// The [CupertinoListSection.insetGrouped] constructor creates a round-edged
   /// and padded section that is seen in iOS Notes and Reminders apps. It creates
   /// an iOS-style header, and the dividers between rows. Does not create borders
   /// on top and bottom of the rows.
   ///
   /// The [header] parameter sets the form section header. The section header
   /// lies above the [children] rows, with margins that match the iOS style.
   ///
   /// The [footer] parameter sets the form section footer. The section footer
   /// lies below the [children] rows.
   ///
   /// The [children] parameter is required and sets the list of rows shown in
   /// the section. The [children] parameter takes a list, as opposed to a more
   /// efficient builder function that lazy builds, because forms are intended to
   /// be short in row count. It is recommended that only [CupertinoListTile]
   /// widget be included in the [children] list in order to retain the iOS look.
   ///
   /// The [margin] parameter sets the spacing around the content area of the
   /// section encapsulating [children], and defaults to the standard
   /// notched-style iOS form padding.
   ///
   /// The [decoration] parameter sets the decoration around [children].
   /// If null, defaults to [CupertinoColors.secondarySystemGroupedBackground].
   /// If null, defaults to 10.0 circular radius when constructing with
   /// [CupertinoListSection.insetGrouped]. Defaults to zero radius for the
   /// standard [CupertinoListSection] constructor.
   ///
   /// The [backgroundColor] parameter sets the background color behind the
   /// section. If null, defaults to [CupertinoColors.systemGroupedBackground].
   ///
   /// The [dividerMargin] parameter sets the starting offset of the divider
   /// between rows.
   ///
   /// The [additionalDividerMargin] parameter adds additional margin to existing
   /// [dividerMargin] when [hasLeading] is set to true. By default, it offsets
   /// for the width of leading and space between leading and title of
   /// [CupertinoListTile], but it can be overwritten for custom look.
   ///
   /// The [hasLeading] parameter specifies whether children [CupertinoListTile]
   /// widgets contain leading or not. Used for calculating correct starting
   /// margin for the divider between rows.
   ///
   /// {@macro flutter.material.Material.clipBehavior}
   const CupertinoListSection.insetGrouped({
     super.key,
     this.children,
     this.header,
     this.footer,
     EdgeInsetsGeometry? margin,
     this.backgroundColor = CupertinoColors.systemGroupedBackground,
     this.decoration,
     this.clipBehavior = Clip.hardEdge,
     this.dividerMargin = _kInsetDividerMargin,
     double? additionalDividerMargin,
     this.topMargin,
     bool hasLeading = true,
   }) : assert((children != null && children.length > 0) || header != null),
        type = CupertinoListSectionType.insetGrouped,
        additionalDividerMargin = additionalDividerMargin ??
            (hasLeading
                ? _kInsetAdditionalDividerMargin
                : _kInsetAdditionalDividerMarginWithoutLeading),
        margin = margin ?? (header == null ? _kDefaultInsetGroupedRowsMargin : _kDefaultInsetGroupedRowsMarginWithHeader);

   /// The type of list section, either base or inset grouped.
   ///
   /// This member is public for testing purposes only and cannot be set
   /// manually. Instead, use a corresponding constructors.
   @visibleForTesting
   final CupertinoListSectionType type;

   /// Sets the form section header. The section header lies above the [children]
   /// rows. Usually a [Text] widget.
   final Widget? header;

   /// Sets the form section footer. The section footer lies below the [children]
   /// rows. Usually a [Text] widget.
   final Widget? footer;

   /// Margin around the content area of the section encapsulating [children].
   ///
   /// Defaults to zero padding if constructed with standard
   /// [CupertinoListSection] constructor. Defaults to the standard notched-style
   /// iOS margin when constructing with [CupertinoListSection.insetGrouped].
   final EdgeInsetsGeometry margin;

   /// The list of rows in the section. Usually a list of [CupertinoListTile]s.
   ///
   /// This takes a list, as opposed to a more efficient builder function that
   /// lazy builds, because such lists are intended to be short in row count.
   /// It is recommended that only [CupertinoListTile] widget be included in the
   /// [children] list in order to retain the iOS look.
   final List<Widget>? children;

   /// Sets the decoration around [children].
   ///
   /// If null, background color defaults to
   /// [CupertinoColors.secondarySystemGroupedBackground].
   ///
   /// If null, border radius defaults to 10.0 circular radius when constructing
   /// with [CupertinoListSection.insetGrouped]. Defaults to zero radius for the
   /// standard [CupertinoListSection] constructor.
   final BoxDecoration? decoration;

   /// Sets the background color behind the section.
   ///
   /// Defaults to [CupertinoColors.systemGroupedBackground].
   final Color backgroundColor;

   /// {@macro flutter.material.Material.clipBehavior}
   ///
   /// Defaults to [Clip.hardEdge].
   final Clip clipBehavior;

   /// The starting offset of a margin between two list tiles.
   final double dividerMargin;

   /// Additional starting inset of the divider used between rows. This is used
   /// when adding a leading icon to children and a divider should start at the
   /// text inset instead of the icon.
   final double additionalDividerMargin;

   /// Margin above the list section. Only used in edge-to-edge variant and it
   /// matches iOS style by default.
   final double? topMargin;

   @override
   Widget build(BuildContext context) {
     final Color dividerColor = CupertinoColors.separator.resolveFrom(context);
     final double dividerHeight = 1.0 / MediaQuery.of(context).devicePixelRatio;

     // Long divider is used for wrapping the top and bottom of rows.
     // Only used in CupertinoListSectionType.base mode.
     final Widget longDivider = Container(
       color: dividerColor,
       height: dividerHeight,
     );

     // Short divider is used between rows.
     final Widget shortDivider = Container(
       margin: EdgeInsetsDirectional.only(
           start: dividerMargin + additionalDividerMargin),
       color: dividerColor,
       height: dividerHeight,
     );

     Widget? headerWidget;
     if (header != null) {
       headerWidget = DefaultTextStyle(
         style: CupertinoTheme.of(context).textTheme.textStyle.merge(
               type == CupertinoListSectionType.base
                   ? TextStyle(
                       fontSize: 13.0,
                       color: CupertinoDynamicColor.resolve(
                           _kHeaderFooterColor, context))
                   : const TextStyle(
                       fontSize: 20.0, fontWeight: FontWeight.bold),
             ),
         child: header!,
       );
     }

     Widget? footerWidget;
     if (footer != null) {
       footerWidget = DefaultTextStyle(
         style: type == CupertinoListSectionType.base
             ? CupertinoTheme.of(context).textTheme.textStyle.merge(TextStyle(
                   fontSize: 13.0,
                   color: CupertinoDynamicColor.resolve(
                       _kHeaderFooterColor, context),
                 ))
             : CupertinoTheme.of(context).textTheme.textStyle,
         child: footer!,
       );
     }

     BorderRadius? childrenGroupBorderRadius;
     DecoratedBox? decoratedChildrenGroup;
     if (children != null && children!.isNotEmpty) {
       // We construct childrenWithDividers as follows:
       // Insert a short divider between all rows.
       // If it is a `CupertinoListSectionType.base` type, add a long divider
       // to the top and bottom of the rows.
       final List<Widget> childrenWithDividers = <Widget>[];

       if (type == CupertinoListSectionType.base) {
         childrenWithDividers.add(longDivider);
       }

       children!.sublist(0, children!.length - 1).forEach((Widget widget) {
         childrenWithDividers.add(widget);
         childrenWithDividers.add(shortDivider);
       });

       childrenWithDividers.add(children!.last);
       if (type == CupertinoListSectionType.base) {
         childrenWithDividers.add(longDivider);
       }

       switch (type) {
         case CupertinoListSectionType.insetGrouped:
           childrenGroupBorderRadius = _kDefaultInsetGroupedBorderRadius;
           break;
         case CupertinoListSectionType.base:
           childrenGroupBorderRadius = BorderRadius.zero;
           break;
       }

       // Refactored the decorate children group in one place to avoid repeating it
       // twice down bellow in the returned widget.
       decoratedChildrenGroup = DecoratedBox(
         decoration: decoration ??
             BoxDecoration(
               color: CupertinoDynamicColor.resolve(
                   decoration?.color ??
                       CupertinoColors.secondarySystemGroupedBackground,
                   context),
               borderRadius: childrenGroupBorderRadius,
             ),
         child: Column(children: childrenWithDividers),
       );
     }

     return DecoratedBox(
       decoration: BoxDecoration(
           color: CupertinoDynamicColor.resolve(backgroundColor, context)),
       child: Column(
         children: <Widget>[
           if (type == CupertinoListSectionType.base)
             SizedBox(height: topMargin),
           if (headerWidget != null)
             Align(
               alignment: AlignmentDirectional.centerStart,
               child: Padding(
                 padding: type == CupertinoListSectionType.base
                     ? _kDefaultHeaderMargin
                     : _kInsetGroupedDefaultHeaderMargin,
                 child: headerWidget,
               ),
             ),
           if (children != null && children!.isNotEmpty)
             Padding(
               padding: margin,
               child: clipBehavior == Clip.none
                   ? decoratedChildrenGroup
                   : ClipRRect(
                       borderRadius: childrenGroupBorderRadius,
                       clipBehavior: clipBehavior,
                       child: decoratedChildrenGroup,
                     ),
             ),
           if (footerWidget != null)
             Align(
               alignment: AlignmentDirectional.centerStart,
               child: Padding(
                 padding: type == CupertinoListSectionType.base
                     ? _kDefaultFooterMargin
                     : _kInsetGroupedDefaultFooterMargin,
                 child: footerWidget,
               ),
             ),
         ],
       ),
     );
   }
 }
	// 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/widgets.dart';

	import 'colors.dart';
	import 'theme.dart';

	// Margin on top of the list section. This was eyeballed from iOS 14.4 Simulator
	// and should be always present on top of the edge-to-edge variant.
	const double _kMarginTop = 22.0;

	// Standard header margin, determined from SwiftUI's Forms in iOS 14.2 SDK.
	const EdgeInsetsDirectional _kDefaultHeaderMargin = EdgeInsetsDirectional.fromSTEB(20.0, 0.0, 20.0, 6.0);

	// Header margin for inset grouped variant, determined from iOS 14.4 Simulator.
	const EdgeInsetsDirectional _kInsetGroupedDefaultHeaderMargin = EdgeInsetsDirectional.fromSTEB(20.0, 16.0, 20.0, 6.0);

	// Standard footer margin, determined from SwiftUI's Forms in iOS 14.2 SDK.
	const EdgeInsetsDirectional _kDefaultFooterMargin = EdgeInsetsDirectional.fromSTEB(20.0, 0.0, 20.0, 0.0);

	// Footer margin for inset grouped variant, determined from iOS 14.4 Simulator.
	const EdgeInsetsDirectional _kInsetGroupedDefaultFooterMargin = EdgeInsetsDirectional.fromSTEB(20.0, 0.0, 20.0, 10.0);

	// Margin around children in edge-to-edge variant, determined from iOS 14.4
	// Simulator.
	const EdgeInsets _kDefaultRowsMargin = EdgeInsets.only(bottom: 8.0);

	// Used for iOS "Inset Grouped" margin, determined from SwiftUI's Forms in
	// iOS 14.2 SDK.
	const EdgeInsetsDirectional _kDefaultInsetGroupedRowsMargin = EdgeInsetsDirectional.fromSTEB(20.0, 20.0, 20.0, 10.0);

	// Used for iOS "Inset Grouped" margin, determined from SwiftUI's Forms in
	// iOS 14.2 SDK.
	const EdgeInsetsDirectional _kDefaultInsetGroupedRowsMarginWithHeader = EdgeInsetsDirectional.fromSTEB(20.0, 0.0, 20.0, 10.0);

	// Used for iOS "Inset Grouped" border radius, estimated from SwiftUI's Forms in
	// iOS 14.2 SDK.
	// TODO(edrisian): This should be a rounded rectangle once that shape is added.
	const BorderRadius _kDefaultInsetGroupedBorderRadius = BorderRadius.all(Radius.circular(10.0));

	// The margin of divider used in base list section. Estimated from iOS 14.4 SDK
	// Settings app.
	const double _kBaseDividerMargin = 20.0;

	// Additional margin of divider used in base list section with list tiles with
	// leading widgets. Estimated from iOS 14.4 SDK Settings app.
	const double _kBaseAdditionalDividerMargin = 44.0;

	// The margin of divider used in inset grouped version of list section.
	// Estimated from iOS 14.4 SDK Reminders app.
	const double _kInsetDividerMargin = 14.0;

	// Additional margin of divider used in inset grouped version of list section.
	// Estimated from iOS 14.4 SDK Reminders app.
	const double _kInsetAdditionalDividerMargin = 42.0;

	// Additional margin of divider used in inset grouped version of list section
	// when there is no leading widgets. Estimated from iOS 14.4 SDK Notes app.
	const double _kInsetAdditionalDividerMarginWithoutLeading = 14.0;

	// Color of header and footer text in edge-to-edge variant.
	const Color _kHeaderFooterColor = CupertinoDynamicColor(
	color: Color.fromRGBO(108, 108, 108, 1.0),
	darkColor: Color.fromRGBO(142, 142, 146, 1.0),
	highContrastColor: Color.fromRGBO(74, 74, 77, 1.0),
	darkHighContrastColor: Color.fromRGBO(176, 176, 183, 1.0),
	elevatedColor: Color.fromRGBO(108, 108, 108, 1.0),
	darkElevatedColor: Color.fromRGBO(142, 142, 146, 1.0),
	highContrastElevatedColor: Color.fromRGBO(108, 108, 108, 1.0),
	darkHighContrastElevatedColor: Color.fromRGBO(142, 142, 146, 1.0),
	);

	/// Denotes what type of the list section a [CupertinoListSection] is.
	///
	/// This is for internal use only.
	enum CupertinoListSectionType {
	/// A basic form of [CupertinoListSection].
	base,

	/// An inset-grouped style of [CupertinoListSection].
	insetGrouped,
	}

	/// An iOS-style list section.
	///
	/// The [CupertinoListSection] is a container for children widgets. These are
	/// most often [CupertinoListTile]s.
	///
	/// The base constructor for [CupertinoListSection] constructs an
	/// edge-to-edge style section which includes an iOS-style header, the dividers
	/// between rows, and borders on top and bottom of the rows. An example of such
	/// list section are sections in iOS Settings app.
	///
	/// The [CupertinoListSection.insetGrouped] constructor creates a round-edged
	/// and padded section that is seen in iOS Notes and Reminders apps. It creates
	/// an iOS-style header, and the dividers between rows. Does not create borders
	/// on top and bottom of the rows.
	///
	/// The section [header] lies above the [children] rows, with margins and style
	/// that match the iOS style.
	///
	/// The section [footer] lies below the [children] rows and is used to provide
	/// additional information for current list section.
	///
	/// The [children] is the list of widgets to be displayed in this list section.
	/// Typically, the children are of type [CupertinoListTile], however these is
	/// not enforced.
	///
	/// The [margin] is used to provide spacing around the content area of the
	/// section encapsulating [children].
	///
	/// The [decoration] of [children] specifies how they should be decorated. If it
	/// is not provided in constructor, the background color of [children] defaults
	/// to [CupertinoColors.secondarySystemGroupedBackground] and border radius of
	/// children group defaults to 10.0 circular radius when constructing with
	/// [CupertinoListSection.insetGrouped]. Defaults to zero radius for the
	/// standard [CupertinoListSection] constructor.
	///
	/// The [dividerMargin] and [additionalDividerMargin] specify the starting
	/// margin of the divider between list tiles. The [dividerMargin] is always
	/// present, but [additionalDividerMargin] is only added to the [dividerMargin]
	/// if `hasLeading` is set to true in the constructor, which is the default
	/// value.
	///
	/// The [backgroundColor] of the section defaults to
	/// [CupertinoColors.systemGroupedBackground].
	///
	/// {@macro flutter.material.Material.clipBehavior}
	///
	/// {@tool dartpad}
	/// Creates a base [CupertinoListSection] containing [CupertinoListTile]s with
	/// `leading`, `title`, `additionalInfo` and `trailing` widgets.
	///
	/// See code in examples/api/lib/cupertino/list_section/list_section_base.0.dart
	/// {@end-tool}
	///
	/// {@tool dartpad}
	/// Creates an "Inset Grouped" [CupertinoListSection] containing
	/// notched [CupertinoListTile]s with `leading`, `title`, `additionalInfo` and
	/// `trailing` widgets.
	///
	/// See code in examples/api/lib/cupertino/list_section/list_section_inset.0.dart
	/// {@end-tool}
	///
	/// See also:
	///
	/// * [CupertinoListTile], an iOS-style list tile, a typical child of
	/// [CupertinoListSection].
	/// * [CupertinoFormSection], an iOS-style form section.
	class CupertinoListSection extends StatelessWidget {
	/// Creates a section that mimics standard iOS forms.
	///
	/// The base constructor for [CupertinoListSection] constructs an
	/// edge-to-edge style section which includes an iOS-style header, the dividers
	/// between rows, and borders on top and bottom of the rows. An example of such
	/// list section are sections in iOS Settings app.
	///
	/// The [header] parameter sets the form section header. The section header
	/// lies above the [children] rows, with margins that match the iOS style.
	///
	/// The [footer] parameter sets the form section footer. The section footer
	/// lies below the [children] rows.
	///
	/// The [children] parameter is required and sets the list of rows shown in
	/// the section. The [children] parameter takes a list, as opposed to a more
	/// efficient builder function that lazy builds, because forms are intended to
	/// be short in row count. It is recommended that only [CupertinoFormRow] and
	/// [CupertinoTextFormFieldRow] widgets be included in the [children] list in
	/// order to retain the iOS look.
	///
	/// The [margin] parameter sets the spacing around the content area of the
	/// section encapsulating [children], and defaults to zero padding.
	///
	/// The [decoration] parameter sets the decoration around [children].
	/// If null, defaults to [CupertinoColors.secondarySystemGroupedBackground].
	/// If null, defaults to 10.0 circular radius when constructing with
	/// [CupertinoListSection.insetGrouped]. Defaults to zero radius for the
	/// standard [CupertinoListSection] constructor.
	///
	/// The [backgroundColor] parameter sets the background color behind the
	/// section. If null, defaults to [CupertinoColors.systemGroupedBackground].
	///
	/// The [dividerMargin] parameter sets the starting offset of the divider
	/// between rows.
	///
	/// The [additionalDividerMargin] parameter adds additional margin to existing
	/// [dividerMargin] when [hasLeading] is set to true. By default, it offsets
	/// for the width of leading and space between leading and title of
	/// [CupertinoListTile], but it can be overwritten for custom look.
	///
	/// The [hasLeading] parameter specifies whether children [CupertinoListTile]
	/// widgets contain leading or not. Used for calculating correct starting
	/// margin for the divider between rows.
	///
	/// The [topMargin] is used to specify the margin above the list section. It
	/// matches the iOS look by default.
	///
	/// {@macro flutter.material.Material.clipBehavior}
	const CupertinoListSection({
	super.key,
	this.children,
	this.header,
	this.footer,
	this.margin = _kDefaultRowsMargin,
	this.backgroundColor = CupertinoColors.systemGroupedBackground,
	this.decoration,
	this.clipBehavior = Clip.none,
	this.dividerMargin = _kBaseDividerMargin,
	double? additionalDividerMargin,
	this.topMargin = _kMarginTop,
	bool hasLeading = true,
	}) : assert((children != null && children.length > 0) \|\| header != null),
	type = CupertinoListSectionType.base,
	additionalDividerMargin = additionalDividerMargin ??
	(hasLeading ? _kBaseAdditionalDividerMargin : 0.0);

	/// Creates a section that mimics standard "Inset Grouped" iOS list section.
	///
	/// The [CupertinoListSection.insetGrouped] constructor creates a round-edged
	/// and padded section that is seen in iOS Notes and Reminders apps. It creates
	/// an iOS-style header, and the dividers between rows. Does not create borders
	/// on top and bottom of the rows.
	///
	/// The [header] parameter sets the form section header. The section header
	/// lies above the [children] rows, with margins that match the iOS style.
	///
	/// The [footer] parameter sets the form section footer. The section footer
	/// lies below the [children] rows.
	///
	/// The [children] parameter is required and sets the list of rows shown in
	/// the section. The [children] parameter takes a list, as opposed to a more
	/// efficient builder function that lazy builds, because forms are intended to
	/// be short in row count. It is recommended that only [CupertinoListTile]
	/// widget be included in the [children] list in order to retain the iOS look.
	///
	/// The [margin] parameter sets the spacing around the content area of the
	/// section encapsulating [children], and defaults to the standard
	/// notched-style iOS form padding.
	///
	/// The [decoration] parameter sets the decoration around [children].
	/// If null, defaults to [CupertinoColors.secondarySystemGroupedBackground].
	/// If null, defaults to 10.0 circular radius when constructing with
	/// [CupertinoListSection.insetGrouped]. Defaults to zero radius for the
	/// standard [CupertinoListSection] constructor.
	///
	/// The [backgroundColor] parameter sets the background color behind the
	/// section. If null, defaults to [CupertinoColors.systemGroupedBackground].
	///
	/// The [dividerMargin] parameter sets the starting offset of the divider
	/// between rows.
	///
	/// The [additionalDividerMargin] parameter adds additional margin to existing
	/// [dividerMargin] when [hasLeading] is set to true. By default, it offsets
	/// for the width of leading and space between leading and title of
	/// [CupertinoListTile], but it can be overwritten for custom look.
	///
	/// The [hasLeading] parameter specifies whether children [CupertinoListTile]
	/// widgets contain leading or not. Used for calculating correct starting
	/// margin for the divider between rows.
	///
	/// {@macro flutter.material.Material.clipBehavior}
	const CupertinoListSection.insetGrouped({
	super.key,
	this.children,
	this.header,
	this.footer,
	EdgeInsetsGeometry? margin,
	this.backgroundColor = CupertinoColors.systemGroupedBackground,
	this.decoration,
	this.clipBehavior = Clip.hardEdge,
	this.dividerMargin = _kInsetDividerMargin,
	double? additionalDividerMargin,
	this.topMargin,
	bool hasLeading = true,
	}) : assert((children != null && children.length > 0) \|\| header != null),
	type = CupertinoListSectionType.insetGrouped,
	additionalDividerMargin = additionalDividerMargin ??
	(hasLeading
	? _kInsetAdditionalDividerMargin
	: _kInsetAdditionalDividerMarginWithoutLeading),
	margin = margin ?? (header == null ? _kDefaultInsetGroupedRowsMargin : _kDefaultInsetGroupedRowsMarginWithHeader);

	/// The type of list section, either base or inset grouped.
	///
	/// This member is public for testing purposes only and cannot be set
	/// manually. Instead, use a corresponding constructors.
	@visibleForTesting
	final CupertinoListSectionType type;

	/// Sets the form section header. The section header lies above the [children]
	/// rows. Usually a [Text] widget.
	final Widget? header;

	/// Sets the form section footer. The section footer lies below the [children]
	/// rows. Usually a [Text] widget.
	final Widget? footer;

	/// Margin around the content area of the section encapsulating [children].
	///
	/// Defaults to zero padding if constructed with standard
	/// [CupertinoListSection] constructor. Defaults to the standard notched-style
	/// iOS margin when constructing with [CupertinoListSection.insetGrouped].
	final EdgeInsetsGeometry margin;

	/// The list of rows in the section. Usually a list of [CupertinoListTile]s.
	///
	/// This takes a list, as opposed to a more efficient builder function that
	/// lazy builds, because such lists are intended to be short in row count.
	/// It is recommended that only [CupertinoListTile] widget be included in the
	/// [children] list in order to retain the iOS look.
	final List<Widget>? children;

	/// Sets the decoration around [children].
	///
	/// If null, background color defaults to
	/// [CupertinoColors.secondarySystemGroupedBackground].
	///
	/// If null, border radius defaults to 10.0 circular radius when constructing
	/// with [CupertinoListSection.insetGrouped]. Defaults to zero radius for the
	/// standard [CupertinoListSection] constructor.
	final BoxDecoration? decoration;

	/// Sets the background color behind the section.
	///
	/// Defaults to [CupertinoColors.systemGroupedBackground].
	final Color backgroundColor;

	/// {@macro flutter.material.Material.clipBehavior}
	///
	/// Defaults to [Clip.hardEdge].
	final Clip clipBehavior;

	/// The starting offset of a margin between two list tiles.
	final double dividerMargin;

	/// Additional starting inset of the divider used between rows. This is used
	/// when adding a leading icon to children and a divider should start at the
	/// text inset instead of the icon.
	final double additionalDividerMargin;

	/// Margin above the list section. Only used in edge-to-edge variant and it
	/// matches iOS style by default.
	final double? topMargin;

	@override
	Widget build(BuildContext context) {
	final Color dividerColor = CupertinoColors.separator.resolveFrom(context);
	final double dividerHeight = 1.0 / MediaQuery.of(context).devicePixelRatio;

	// Long divider is used for wrapping the top and bottom of rows.
	// Only used in CupertinoListSectionType.base mode.
	final Widget longDivider = Container(
	color: dividerColor,
	height: dividerHeight,
	);

	// Short divider is used between rows.
	final Widget shortDivider = Container(
	margin: EdgeInsetsDirectional.only(
	start: dividerMargin + additionalDividerMargin),
	color: dividerColor,
	height: dividerHeight,
	);

	Widget? headerWidget;
	if (header != null) {
	headerWidget = DefaultTextStyle(
	style: CupertinoTheme.of(context).textTheme.textStyle.merge(
	type == CupertinoListSectionType.base
	? TextStyle(
	fontSize: 13.0,
	color: CupertinoDynamicColor.resolve(
	_kHeaderFooterColor, context))
	: const TextStyle(
	fontSize: 20.0, fontWeight: FontWeight.bold),
	),
	child: header!,
	);
	}

	Widget? footerWidget;
	if (footer != null) {
	footerWidget = DefaultTextStyle(
	style: type == CupertinoListSectionType.base
	? CupertinoTheme.of(context).textTheme.textStyle.merge(TextStyle(
	fontSize: 13.0,
	color: CupertinoDynamicColor.resolve(
	_kHeaderFooterColor, context),
	))
	: CupertinoTheme.of(context).textTheme.textStyle,
	child: footer!,
	);
	}

	BorderRadius? childrenGroupBorderRadius;
	DecoratedBox? decoratedChildrenGroup;
	if (children != null && children!.isNotEmpty) {
	// We construct childrenWithDividers as follows:
	// Insert a short divider between all rows.
	// If it is a `CupertinoListSectionType.base` type, add a long divider
	// to the top and bottom of the rows.
	final List<Widget> childrenWithDividers = <Widget>[];

	if (type == CupertinoListSectionType.base) {
	childrenWithDividers.add(longDivider);
	}

	children!.sublist(0, children!.length - 1).forEach((Widget widget) {
	childrenWithDividers.add(widget);
	childrenWithDividers.add(shortDivider);
	});

	childrenWithDividers.add(children!.last);
	if (type == CupertinoListSectionType.base) {
	childrenWithDividers.add(longDivider);
	}

	switch (type) {
	case CupertinoListSectionType.insetGrouped:
	childrenGroupBorderRadius = _kDefaultInsetGroupedBorderRadius;
	break;
	case CupertinoListSectionType.base:
	childrenGroupBorderRadius = BorderRadius.zero;
	break;
	}

	// Refactored the decorate children group in one place to avoid repeating it
	// twice down bellow in the returned widget.
	decoratedChildrenGroup = DecoratedBox(
	decoration: decoration ??
	BoxDecoration(
	color: CupertinoDynamicColor.resolve(
	decoration?.color ??
	CupertinoColors.secondarySystemGroupedBackground,
	context),
	borderRadius: childrenGroupBorderRadius,
	),
	child: Column(children: childrenWithDividers),
	);
	}

	return DecoratedBox(
	decoration: BoxDecoration(
	color: CupertinoDynamicColor.resolve(backgroundColor, context)),
	child: Column(
	children: <Widget>[
	if (type == CupertinoListSectionType.base)
	SizedBox(height: topMargin),
	if (headerWidget != null)
	Align(
	alignment: AlignmentDirectional.centerStart,
	child: Padding(
	padding: type == CupertinoListSectionType.base
	? _kDefaultHeaderMargin
	: _kInsetGroupedDefaultHeaderMargin,
	child: headerWidget,
	),
	),
	if (children != null && children!.isNotEmpty)
	Padding(
	padding: margin,
	child: clipBehavior == Clip.none
	? decoratedChildrenGroup
	: ClipRRect(
	borderRadius: childrenGroupBorderRadius,
	clipBehavior: clipBehavior,
	child: decoratedChildrenGroup,
	),
	),
	if (footerWidget != null)
	Align(
	alignment: AlignmentDirectional.centerStart,
	child: Padding(
	padding: type == CupertinoListSectionType.base
	? _kDefaultFooterMargin
	: _kInsetGroupedDefaultFooterMargin,
	child: footerWidget,
	),
	),
	],
	),
	);
	}
	}