packages/flutter/lib/src/cupertino/radio.dart - mirrors/flutter.git - 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.

 /// @docImport 'package:flutter/material.dart';
 ///
 /// @docImport 'checkbox.dart';
 /// @docImport 'slider.dart';
 /// @docImport 'switch.dart';
 library;

 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';

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

 // Examples can assume:
 // late BuildContext context;
 // enum SingingCharacter { lafayette }
 // late SingingCharacter? _character;
 // late StateSetter setState;

 const Size _size = Size(18.0, 18.0);
 const double _kOuterRadius = 7.0;
 const double _kInnerRadius = 2.975;

 // Eyeballed from a radio on a physical Macbook Pro running macOS version 14.5.
 final Color _kDisabledOuterColor = CupertinoColors.white.withOpacity(0.50);
 const Color _kDisabledInnerColor = CupertinoDynamicColor.withBrightness(
   color: Color.fromARGB(64, 0, 0, 0),
   darkColor: Color.fromARGB(64, 255, 255, 255),
 );
 const Color _kDisabledBorderColor = CupertinoDynamicColor.withBrightness(
   color: Color.fromARGB(64, 0, 0, 0),
   darkColor: Color.fromARGB(64, 0, 0, 0),
 );
 const CupertinoDynamicColor _kDefaultBorderColor = CupertinoDynamicColor.withBrightness(
   color: Color.fromARGB(255, 209, 209, 214),
   darkColor: Color.fromARGB(64, 0, 0, 0),
 );
 const CupertinoDynamicColor _kDefaultInnerColor = CupertinoDynamicColor.withBrightness(
   color: CupertinoColors.white,
   darkColor: Color.fromARGB(255, 222, 232, 248),
 );
 const CupertinoDynamicColor _kDefaultOuterColor = CupertinoDynamicColor.withBrightness(
   color: CupertinoColors.activeBlue,
   darkColor: Color.fromARGB(255, 50, 100, 215),
 );
 const double _kPressedOverlayOpacity = 0.15;
 const double _kCheckmarkStrokeWidth = 2.0;
 const double _kFocusOutlineStrokeWidth = 3.0;
 const double _kBorderOutlineStrokeWidth = 0.3;
 // In dark mode, the outer color of a radio is an opacity gradient of the
 // background color.
 const List<double> _kDarkGradientOpacities = <double>[0.14, 0.29];
 const List<double> _kDisabledDarkGradientOpacities = <double>[0.08, 0.14];

 /// A widget that builds a [RawRadio] with a macOS-style UI.
 ///
 /// {@youtube 560 315 https://www.youtube.com/watch?v=D0xwcz2IqAY}
 ///
 /// Used to select between a number of mutually exclusive values. When one radio
 /// button in a group is selected, the other radio buttons in the group are
 /// deselected. The values are of type `T`, the type parameter of the
 /// [CupertinoRadio] class. Enums are commonly used for this purpose.
 ///
 /// This widget typically has a [RadioGroup] ancestor, which takes in a
 /// [RadioGroup.groupValue], and the [CupertinoRadio] under it with matching
 /// [value] will be selected.
 ///
 /// {@tool dartpad}
 /// Here is an example of CupertinoRadio widgets wrapped in CupertinoListTiles.
 ///
 /// The currently selected character is passed into `RadioGroup.groupValue`, which is
 /// maintained by the example's `State`. In this case, the first [CupertinoRadio]
 /// will start off selected because `_character` is initialized to
 /// `SingingCharacter.lafayette`.
 ///
 /// If the second radio button is pressed, the example's state is updated
 /// with `setState`, updating `_character` to `SingingCharacter.jefferson`.
 /// This causes the buttons to rebuild with the updated `RadioGroup.groupValue`, and
 /// therefore the selection of the second button.
 ///
 /// ** See code in examples/api/lib/cupertino/radio/cupertino_radio.0.dart **
 /// {@end-tool}
 ///
 /// See also:
 ///
 ///  * [CupertinoSlider], for selecting a value in a range.
 ///  * [CupertinoCheckbox] and [CupertinoSwitch], for toggling a particular value on or off.
 ///  * [Radio], the Material Design equivalent.
 ///  * <https://developer.apple.com/design/human-interface-guidelines/components/selection-and-input/toggles/>
 class CupertinoRadio<T> extends StatefulWidget {
   /// Creates a macOS-styled radio button.
   ///
   /// The following arguments are required:
   ///
   /// * [value] and [groupValue] together determine whether the radio button is
   ///   selected.
   /// * [onChanged] is called when the user selects this radio button.
   const CupertinoRadio({
     super.key,
     required this.value,
     @Deprecated(
       'Use a RadioGroup ancestor to manage group value instead. '
       'This feature was deprecated after v3.32.0-0.0.pre.',
     )
     this.groupValue,
     @Deprecated(
       'Use RadioGroup to handle value change instead. '
       'This feature was deprecated after v3.32.0-0.0.pre.',
     )
     this.onChanged,
     this.mouseCursor,
     this.toggleable = false,
     this.activeColor,
     this.inactiveColor,
     this.fillColor,
     this.focusColor,
     this.focusNode,
     this.autofocus = false,
     this.useCheckmarkStyle = false,
     this.enabled,
     this.groupRegistry,
   });

   /// {@macro flutter.widget.RawRadio.value}
   final T value;

   /// {@macro flutter.material.Radio.groupValue}
   @Deprecated(
     'Use a RadioGroup ancestor to manage group value instead. '
     'This feature was deprecated after v3.32.0-0.0.pre.',
   )
   final T? groupValue;

   /// {@macro flutter.material.Radio.onChanged}
   ///
   /// For example:
   ///
   /// ```dart
   /// CupertinoRadio<SingingCharacter>(
   ///   value: SingingCharacter.lafayette,
   ///   // ignore: deprecated_member_use
   ///   groupValue: _character,
   ///   // ignore: deprecated_member_use
   ///   onChanged: (SingingCharacter? newValue) {
   ///     setState(() {
   ///       _character = newValue;
   ///     });
   ///   },
   /// )
   /// ```
   @Deprecated(
     'Use RadioGroup to handle value change instead. '
     'This feature was deprecated after v3.32.0-0.0.pre.',
   )
   final ValueChanged<T?>? onChanged;

   /// {@macro flutter.widget.RawRadio.mouseCursor}
   ///
   /// If null, then [SystemMouseCursors.basic] is used when this radio button is disabled.
   /// When this radio button is enabled, [SystemMouseCursors.click] is used on Web, and
   /// [SystemMouseCursors.basic] is used on other platforms.
   ///
   /// See also:
   ///
   ///  * [WidgetStateMouseCursor], a [MouseCursor] that implements
   ///    `WidgetStateProperty` which is used in APIs that need to accept
   ///    either a [MouseCursor] or a [WidgetStateProperty<MouseCursor>].
   final MouseCursor? mouseCursor;

   /// {@macro flutter.widget.RawRadio.toggleable}
   ///
   /// {@tool dartpad}
   /// This example shows how to enable deselecting a radio button by setting the
   /// [toggleable] attribute.
   ///
   /// ** See code in examples/api/lib/cupertino/radio/cupertino_radio.toggleable.0.dart **
   /// {@end-tool}
   final bool toggleable;

   /// Controls whether the radio displays in a checkbox style or the default iOS
   /// radio style.
   ///
   /// Defaults to false.
   final bool useCheckmarkStyle;

   /// The color to use when this radio button is selected.
   ///
   /// Defaults to [CupertinoColors.activeBlue].
   final Color? activeColor;

   /// The color to use when this radio button is not selected.
   ///
   /// Defaults to [CupertinoColors.white].
   final Color? inactiveColor;

   /// The color that fills the inner circle of the radio button when selected.
   ///
   /// Defaults to [CupertinoColors.white].
   final Color? fillColor;

   /// The color for the radio's border when it has the input focus.
   ///
   /// If null, then a paler form of the [activeColor] will be used.
   final Color? focusColor;

   /// {@macro flutter.widgets.Focus.focusNode}
   final FocusNode? focusNode;

   /// {@macro flutter.widgets.Focus.autofocus}
   final bool autofocus;

   /// {@macro flutter.widget.RawRadio.groupRegistry}
   ///
   /// Unless provided, the [BuildContext] will be used to look up the ancestor
   /// [RadioGroupRegistry].
   final RadioGroupRegistry<T>? groupRegistry;

   /// {@macro flutter.material.Radio.enabled}
   final bool? enabled;

   @override
   State<CupertinoRadio<T>> createState() => _CupertinoRadioState<T>();
 }

 class _CupertinoRadioState<T> extends State<CupertinoRadio<T>> {
   FocusNode get _effectiveFocusNode => widget.focusNode ?? (_internalFocusNode ??= FocusNode());
   FocusNode? _internalFocusNode;

   bool get _enabled =>
       widget.enabled ??
       (widget.onChanged != null ||
           widget.groupRegistry != null ||
           RadioGroup.maybeOf<T>(context) != null);

   _RadioRegistry<T>? _internalRadioRegistry;
   RadioGroupRegistry<T> get _effectiveRegistry {
     if (widget.groupRegistry != null) {
       return widget.groupRegistry!;
     }

     final RadioGroupRegistry<T>? inheritedRegistry = RadioGroup.maybeOf<T>(context);
     if (inheritedRegistry != null) {
       return inheritedRegistry;
     }

     // Handles deprecated API.
     return _internalRadioRegistry ??= _RadioRegistry<T>(this);
   }

   @override
   void dispose() {
     _internalFocusNode?.dispose();
     super.dispose();
   }

   @override
   Widget build(BuildContext context) {
     assert(
       !(widget.enabled ?? false) ||
           widget.onChanged != null ||
           widget.groupRegistry != null ||
           RadioGroup.maybeOf<T>(context) != null,
       'Radio is enabled but has no CupertinoRadio.onChange, '
       'CupertinoRadio.groupRegistry, or RadioGroup above',
     );
     final WidgetStateProperty<MouseCursor> effectiveMouseCursor =
         WidgetStateProperty.resolveWith<MouseCursor>((Set<WidgetState> states) {
           return WidgetStateProperty.resolveAs<MouseCursor?>(widget.mouseCursor, states) ??
               (!states.contains(WidgetState.disabled) && kIsWeb
                   ? SystemMouseCursors.click
                   : SystemMouseCursors.basic);
         });

     return RawRadio<T>(
       value: widget.value,
       groupRegistry: _effectiveRegistry,
       mouseCursor: effectiveMouseCursor,
       toggleable: widget.toggleable,
       focusNode: _effectiveFocusNode,
       autofocus: widget.autofocus,
       enabled: _enabled,
       builder: (BuildContext context, ToggleableStateMixin state) {
         return _RadioPaint(
           activeColor: widget.activeColor,
           inactiveColor: widget.inactiveColor,
           fillColor: widget.fillColor,
           focusColor: widget.focusColor,
           useCheckmarkStyle: widget.useCheckmarkStyle,
           isActive: _enabled,
           toggleableState: state,
           focused: _effectiveFocusNode.hasFocus,
         );
       },
     );
   }
 }

 /// A registry for deprecated API.
 // TODO(chunhtai): Remove this once deprecated API is removed.
 class _RadioRegistry<T> extends RadioGroupRegistry<T> {
   _RadioRegistry(this.state);
   final _CupertinoRadioState<T> state;
   @override
   T? get groupValue => state.widget.groupValue;

   @override
   ValueChanged<T?> get onChanged => state.widget.onChanged!;

   @override
   void registerClient(RadioClient<T> radio) {}

   @override
   void unregisterClient(RadioClient<T> radio) {}
 }

 class _RadioPaint extends StatefulWidget {
   const _RadioPaint({
     required this.focused,
     required this.toggleableState,
     required this.activeColor,
     required this.inactiveColor,
     required this.fillColor,
     required this.focusColor,
     required this.useCheckmarkStyle,
     required this.isActive,
   });

   final ToggleableStateMixin toggleableState;
   final Color? activeColor;
   final Color? inactiveColor;
   final Color? fillColor;
   final Color? focusColor;
   final bool useCheckmarkStyle;
   final bool isActive;

   final bool focused;
   @override
   State<StatefulWidget> createState() => _RadioPaintState();
 }

 class _RadioPaintState extends State<_RadioPaint> {
   final _RadioPainter _painter = _RadioPainter();

   @override
   void dispose() {
     _painter.dispose();
     super.dispose();
   }

   WidgetStateProperty<Color> get _defaultOuterColor {
     return WidgetStateProperty.resolveWith((Set<WidgetState> states) {
       if (states.contains(WidgetState.disabled)) {
         return CupertinoDynamicColor.resolve(_kDisabledOuterColor, context);
       }
       if (states.contains(WidgetState.selected)) {
         return widget.activeColor ?? CupertinoDynamicColor.resolve(_kDefaultOuterColor, context);
       }
       return widget.inactiveColor ?? CupertinoColors.white;
     });
   }

   WidgetStateProperty<Color> get _defaultInnerColor {
     return WidgetStateProperty.resolveWith((Set<WidgetState> states) {
       if (states.contains(WidgetState.disabled) && states.contains(WidgetState.selected)) {
         return widget.fillColor ?? CupertinoDynamicColor.resolve(_kDisabledInnerColor, context);
       }
       if (states.contains(WidgetState.selected)) {
         return widget.fillColor ?? CupertinoDynamicColor.resolve(_kDefaultInnerColor, context);
       }
       return CupertinoColors.white;
     });
   }

   WidgetStateProperty<Color> get _defaultBorderColor {
     return WidgetStateProperty.resolveWith((Set<WidgetState> states) {
       if ((states.contains(WidgetState.selected) || states.contains(WidgetState.focused)) &&
           !states.contains(WidgetState.disabled)) {
         return CupertinoColors.transparent;
       }
       if (states.contains(WidgetState.disabled)) {
         return CupertinoDynamicColor.resolve(_kDisabledBorderColor, context);
       }
       return CupertinoDynamicColor.resolve(_kDefaultBorderColor, context);
     });
   }

   @override
   Widget build(BuildContext context) {
     // Colors need to be resolved in selected and non selected states separately.
     final Set<WidgetState> activeStates = widget.toggleableState.states..add(WidgetState.selected);
     final Set<WidgetState> inactiveStates = widget.toggleableState.states
       ..remove(WidgetState.selected);

     // Since the states getter always makes a new set, make a copy to use
     // throughout the lifecycle of this build method.
     final Set<WidgetState> currentStates = widget.toggleableState.states;

     final Color effectiveActiveColor = _defaultOuterColor.resolve(activeStates);

     final Color effectiveInactiveColor = _defaultOuterColor.resolve(inactiveStates);

     final Color effectiveFocusOverlayColor =
         widget.focusColor ??
         HSLColor.fromColor(effectiveActiveColor.withOpacity(kCupertinoFocusColorOpacity))
             .withLightness(kCupertinoFocusColorBrightness)
             .withSaturation(kCupertinoFocusColorSaturation)
             .toColor();

     final Color effectiveFillColor = _defaultInnerColor.resolve(currentStates);

     final Color effectiveBorderColor = _defaultBorderColor.resolve(currentStates);

     return CustomPaint(
       size: _size,
       painter: _painter
         ..position = widget.toggleableState.position
         ..reaction = widget.toggleableState.reaction
         ..focusColor = effectiveFocusOverlayColor
         ..downPosition = widget.toggleableState.downPosition
         ..isFocused = widget.focused
         ..activeColor = effectiveActiveColor
         ..inactiveColor = effectiveInactiveColor
         ..fillColor = effectiveFillColor
         ..value = widget.toggleableState.value
         ..checkmarkStyle = widget.useCheckmarkStyle
         ..isActive = widget.isActive
         ..borderColor = effectiveBorderColor
         ..brightness = CupertinoTheme.of(context).brightness,
     );
   }
 }

 class _RadioPainter extends ToggleablePainter {
   bool? get value => _value;
   bool? _value;
   set value(bool? value) {
     if (_value == value) {
       return;
     }
     _value = value;
     notifyListeners();
   }

   Color get fillColor => _fillColor!;
   Color? _fillColor;
   set fillColor(Color value) {
     if (value == _fillColor) {
       return;
     }
     _fillColor = value;
     notifyListeners();
   }

   bool get checkmarkStyle => _checkmarkStyle;
   bool _checkmarkStyle = false;
   set checkmarkStyle(bool value) {
     if (value == _checkmarkStyle) {
       return;
     }
     _checkmarkStyle = value;
     notifyListeners();
   }

   Brightness? get brightness => _brightness;
   Brightness? _brightness;
   set brightness(Brightness? value) {
     if (_brightness == value) {
       return;
     }
     _brightness = value;
     notifyListeners();
   }

   Color get borderColor => _borderColor!;
   Color? _borderColor;
   set borderColor(Color value) {
     if (_borderColor == value) {
       return;
     }
     _borderColor = value;
     notifyListeners();
   }

   void _drawPressedOverlay(Canvas canvas, Offset center, double radius) {
     final pressedPaint = Paint()
       ..color = brightness == Brightness.light
           ? CupertinoColors.black.withOpacity(_kPressedOverlayOpacity)
           : CupertinoColors.white.withOpacity(_kPressedOverlayOpacity);
     canvas.drawCircle(center, radius, pressedPaint);
   }

   void _drawFillGradient(
     Canvas canvas,
     Offset center,
     double radius,
     Color topColor,
     Color bottomColor,
   ) {
     final fillGradient = LinearGradient(
       begin: Alignment.topCenter,
       end: Alignment.bottomCenter,
       colors: <Color>[topColor, bottomColor],
     );
     final circleRect = Rect.fromCircle(center: center, radius: radius);
     final gradientPaint = Paint()..shader = fillGradient.createShader(circleRect);
     canvas.drawPath(Path()..addOval(circleRect), gradientPaint);
   }

   void _drawOuterBorder(Canvas canvas, Offset center) {
     final borderPaint = Paint()
       ..style = PaintingStyle.stroke
       ..color = borderColor
       ..strokeWidth = _kBorderOutlineStrokeWidth;
     canvas.drawCircle(center, _kOuterRadius, borderPaint);
   }

   @override
   void paint(Canvas canvas, Size size) {
     final Offset center = (Offset.zero & size).center;

     if (checkmarkStyle) {
       if (value ?? false) {
         final path = Path();
         final checkPaint = Paint()
           ..color = activeColor
           ..style = PaintingStyle.stroke
           ..strokeWidth = _kCheckmarkStrokeWidth
           ..strokeCap = StrokeCap.round;
         final double width = _size.width;
         final origin = Offset(center.dx - (width / 2), center.dy - (width / 2));
         final start = Offset(width * 0.25, width * 0.52);
         final mid = Offset(width * 0.46, width * 0.75);
         final end = Offset(width * 0.85, width * 0.29);
         path.moveTo(origin.dx + start.dx, origin.dy + start.dy);
         path.lineTo(origin.dx + mid.dx, origin.dy + mid.dy);
         canvas.drawPath(path, checkPaint);
         path.moveTo(origin.dx + mid.dx, origin.dy + mid.dy);
         path.lineTo(origin.dx + end.dx, origin.dy + end.dy);
         canvas.drawPath(path, checkPaint);
       }
     } else {
       if (value ?? false) {
         final outerPaint = Paint()..color = activeColor;
         // Draw a gradient in dark mode if the radio is disabled.
         if (brightness == Brightness.dark && !isActive) {
           _drawFillGradient(
             canvas,
             center,
             _kOuterRadius,
             outerPaint.color.withOpacity(
               isActive ? _kDarkGradientOpacities[0] : _kDisabledDarkGradientOpacities[0],
             ),
             outerPaint.color.withOpacity(
               isActive ? _kDarkGradientOpacities[1] : _kDisabledDarkGradientOpacities[1],
             ),
           );
         } else {
           canvas.drawCircle(center, _kOuterRadius, outerPaint);
         }
         // The outer circle's opacity changes when the radio is pressed.
         if (downPosition != null) {
           _drawPressedOverlay(canvas, center, _kOuterRadius);
         }
         final innerPaint = Paint()..color = fillColor;
         canvas.drawCircle(center, _kInnerRadius, innerPaint);
         // Draw an outer border if the radio is disabled and selected.
         if (!isActive) {
           _drawOuterBorder(canvas, center);
         }
       } else {
         final paint = Paint();
         paint.color = isActive ? inactiveColor : _kDisabledOuterColor;
         if (brightness == Brightness.dark) {
           _drawFillGradient(
             canvas,
             center,
             _kOuterRadius,
             paint.color.withOpacity(
               isActive ? _kDarkGradientOpacities[0] : _kDisabledDarkGradientOpacities[0],
             ),
             paint.color.withOpacity(
               isActive ? _kDarkGradientOpacities[1] : _kDisabledDarkGradientOpacities[1],
             ),
           );
         } else {
           canvas.drawCircle(center, _kOuterRadius, paint);
         }
         // The entire circle's opacity changes when the radio is pressed.
         if (downPosition != null) {
           _drawPressedOverlay(canvas, center, _kOuterRadius);
         }
         _drawOuterBorder(canvas, center);
       }
     }
     if (isFocused) {
       final focusPaint = Paint()
         ..style = PaintingStyle.stroke
         ..color = focusColor
         ..strokeWidth = _kFocusOutlineStrokeWidth;
       canvas.drawCircle(center, _kOuterRadius + _kFocusOutlineStrokeWidth / 2, focusPaint);
     }
   }
 }
	// 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.

	/// @docImport 'package:flutter/material.dart';
	///
	/// @docImport 'checkbox.dart';
	/// @docImport 'slider.dart';
	/// @docImport 'switch.dart';
	library;

	import 'package:flutter/foundation.dart';
	import 'package:flutter/widgets.dart';

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

	// Examples can assume:
	// late BuildContext context;
	// enum SingingCharacter { lafayette }
	// late SingingCharacter? _character;
	// late StateSetter setState;

	const Size _size = Size(18.0, 18.0);
	const double _kOuterRadius = 7.0;
	const double _kInnerRadius = 2.975;

	// Eyeballed from a radio on a physical Macbook Pro running macOS version 14.5.
	final Color _kDisabledOuterColor = CupertinoColors.white.withOpacity(0.50);
	const Color _kDisabledInnerColor = CupertinoDynamicColor.withBrightness(
	color: Color.fromARGB(64, 0, 0, 0),
	darkColor: Color.fromARGB(64, 255, 255, 255),
	);
	const Color _kDisabledBorderColor = CupertinoDynamicColor.withBrightness(
	color: Color.fromARGB(64, 0, 0, 0),
	darkColor: Color.fromARGB(64, 0, 0, 0),
	);
	const CupertinoDynamicColor _kDefaultBorderColor = CupertinoDynamicColor.withBrightness(
	color: Color.fromARGB(255, 209, 209, 214),
	darkColor: Color.fromARGB(64, 0, 0, 0),
	);
	const CupertinoDynamicColor _kDefaultInnerColor = CupertinoDynamicColor.withBrightness(
	color: CupertinoColors.white,
	darkColor: Color.fromARGB(255, 222, 232, 248),
	);
	const CupertinoDynamicColor _kDefaultOuterColor = CupertinoDynamicColor.withBrightness(
	color: CupertinoColors.activeBlue,
	darkColor: Color.fromARGB(255, 50, 100, 215),
	);
	const double _kPressedOverlayOpacity = 0.15;
	const double _kCheckmarkStrokeWidth = 2.0;
	const double _kFocusOutlineStrokeWidth = 3.0;
	const double _kBorderOutlineStrokeWidth = 0.3;
	// In dark mode, the outer color of a radio is an opacity gradient of the
	// background color.
	const List<double> _kDarkGradientOpacities = <double>[0.14, 0.29];
	const List<double> _kDisabledDarkGradientOpacities = <double>[0.08, 0.14];

	/// A widget that builds a [RawRadio] with a macOS-style UI.
	///
	/// {@youtube 560 315 https://www.youtube.com/watch?v=D0xwcz2IqAY}
	///
	/// Used to select between a number of mutually exclusive values. When one radio
	/// button in a group is selected, the other radio buttons in the group are
	/// deselected. The values are of type `T`, the type parameter of the
	/// [CupertinoRadio] class. Enums are commonly used for this purpose.
	///
	/// This widget typically has a [RadioGroup] ancestor, which takes in a
	/// [RadioGroup.groupValue], and the [CupertinoRadio] under it with matching
	/// [value] will be selected.
	///
	/// {@tool dartpad}
	/// Here is an example of CupertinoRadio widgets wrapped in CupertinoListTiles.
	///
	/// The currently selected character is passed into `RadioGroup.groupValue`, which is
	/// maintained by the example's `State`. In this case, the first [CupertinoRadio]
	/// will start off selected because `_character` is initialized to
	/// `SingingCharacter.lafayette`.
	///
	/// If the second radio button is pressed, the example's state is updated
	/// with `setState`, updating `_character` to `SingingCharacter.jefferson`.
	/// This causes the buttons to rebuild with the updated `RadioGroup.groupValue`, and
	/// therefore the selection of the second button.
	///
	/// See code in examples/api/lib/cupertino/radio/cupertino_radio.0.dart
	/// {@end-tool}
	///
	/// See also:
	///
	/// * [CupertinoSlider], for selecting a value in a range.
	/// * [CupertinoCheckbox] and [CupertinoSwitch], for toggling a particular value on or off.
	/// * [Radio], the Material Design equivalent.
	/// * <https://developer.apple.com/design/human-interface-guidelines/components/selection-and-input/toggles/>
	class CupertinoRadio<T> extends StatefulWidget {
	/// Creates a macOS-styled radio button.
	///
	/// The following arguments are required:
	///
	/// * [value] and [groupValue] together determine whether the radio button is
	/// selected.
	/// * [onChanged] is called when the user selects this radio button.
	const CupertinoRadio({
	super.key,
	required this.value,
	@Deprecated(
	'Use a RadioGroup ancestor to manage group value instead. '
	'This feature was deprecated after v3.32.0-0.0.pre.',
	)
	this.groupValue,
	@Deprecated(
	'Use RadioGroup to handle value change instead. '
	'This feature was deprecated after v3.32.0-0.0.pre.',
	)
	this.onChanged,
	this.mouseCursor,
	this.toggleable = false,
	this.activeColor,
	this.inactiveColor,
	this.fillColor,
	this.focusColor,
	this.focusNode,
	this.autofocus = false,
	this.useCheckmarkStyle = false,
	this.enabled,
	this.groupRegistry,
	});

	/// {@macro flutter.widget.RawRadio.value}
	final T value;

	/// {@macro flutter.material.Radio.groupValue}
	@Deprecated(
	'Use a RadioGroup ancestor to manage group value instead. '
	'This feature was deprecated after v3.32.0-0.0.pre.',
	)
	final T? groupValue;

	/// {@macro flutter.material.Radio.onChanged}
	///
	/// For example:
	///
	/// ```dart
	/// CupertinoRadio<SingingCharacter>(
	/// value: SingingCharacter.lafayette,
	/// // ignore: deprecated_member_use
	/// groupValue: _character,
	/// // ignore: deprecated_member_use
	/// onChanged: (SingingCharacter? newValue) {
	/// setState(() {
	/// _character = newValue;
	/// });
	/// },
	/// )
	/// ```
	@Deprecated(
	'Use RadioGroup to handle value change instead. '
	'This feature was deprecated after v3.32.0-0.0.pre.',
	)
	final ValueChanged<T?>? onChanged;

	/// {@macro flutter.widget.RawRadio.mouseCursor}
	///
	/// If null, then [SystemMouseCursors.basic] is used when this radio button is disabled.
	/// When this radio button is enabled, [SystemMouseCursors.click] is used on Web, and
	/// [SystemMouseCursors.basic] is used on other platforms.
	///
	/// See also:
	///
	/// * [WidgetStateMouseCursor], a [MouseCursor] that implements
	/// `WidgetStateProperty` which is used in APIs that need to accept
	/// either a [MouseCursor] or a [WidgetStateProperty<MouseCursor>].
	final MouseCursor? mouseCursor;

	/// {@macro flutter.widget.RawRadio.toggleable}
	///
	/// {@tool dartpad}
	/// This example shows how to enable deselecting a radio button by setting the
	/// [toggleable] attribute.
	///
	/// See code in examples/api/lib/cupertino/radio/cupertino_radio.toggleable.0.dart
	/// {@end-tool}
	final bool toggleable;

	/// Controls whether the radio displays in a checkbox style or the default iOS
	/// radio style.
	///
	/// Defaults to false.
	final bool useCheckmarkStyle;

	/// The color to use when this radio button is selected.
	///
	/// Defaults to [CupertinoColors.activeBlue].
	final Color? activeColor;

	/// The color to use when this radio button is not selected.
	///
	/// Defaults to [CupertinoColors.white].
	final Color? inactiveColor;

	/// The color that fills the inner circle of the radio button when selected.
	///
	/// Defaults to [CupertinoColors.white].
	final Color? fillColor;

	/// The color for the radio's border when it has the input focus.
	///
	/// If null, then a paler form of the [activeColor] will be used.
	final Color? focusColor;

	/// {@macro flutter.widgets.Focus.focusNode}
	final FocusNode? focusNode;

	/// {@macro flutter.widgets.Focus.autofocus}
	final bool autofocus;

	/// {@macro flutter.widget.RawRadio.groupRegistry}
	///
	/// Unless provided, the [BuildContext] will be used to look up the ancestor
	/// [RadioGroupRegistry].
	final RadioGroupRegistry<T>? groupRegistry;

	/// {@macro flutter.material.Radio.enabled}
	final bool? enabled;

	@override
	State<CupertinoRadio<T>> createState() => _CupertinoRadioState<T>();
	}

	class _CupertinoRadioState<T> extends State<CupertinoRadio<T>> {
	FocusNode get _effectiveFocusNode => widget.focusNode ?? (_internalFocusNode ??= FocusNode());
	FocusNode? _internalFocusNode;

	bool get _enabled =>
	widget.enabled ??
	(widget.onChanged != null \|\|
	widget.groupRegistry != null \|\|
	RadioGroup.maybeOf<T>(context) != null);

	_RadioRegistry<T>? _internalRadioRegistry;
	RadioGroupRegistry<T> get _effectiveRegistry {
	if (widget.groupRegistry != null) {
	return widget.groupRegistry!;
	}

	final RadioGroupRegistry<T>? inheritedRegistry = RadioGroup.maybeOf<T>(context);
	if (inheritedRegistry != null) {
	return inheritedRegistry;
	}

	// Handles deprecated API.
	return _internalRadioRegistry ??= _RadioRegistry<T>(this);
	}

	@override
	void dispose() {
	_internalFocusNode?.dispose();
	super.dispose();
	}

	@override
	Widget build(BuildContext context) {
	assert(
	!(widget.enabled ?? false) \|\|
	widget.onChanged != null \|\|
	widget.groupRegistry != null \|\|
	RadioGroup.maybeOf<T>(context) != null,
	'Radio is enabled but has no CupertinoRadio.onChange, '
	'CupertinoRadio.groupRegistry, or RadioGroup above',
	);
	final WidgetStateProperty<MouseCursor> effectiveMouseCursor =
	WidgetStateProperty.resolveWith<MouseCursor>((Set<WidgetState> states) {
	return WidgetStateProperty.resolveAs<MouseCursor?>(widget.mouseCursor, states) ??
	(!states.contains(WidgetState.disabled) && kIsWeb
	? SystemMouseCursors.click
	: SystemMouseCursors.basic);
	});

	return RawRadio<T>(
	value: widget.value,
	groupRegistry: _effectiveRegistry,
	mouseCursor: effectiveMouseCursor,
	toggleable: widget.toggleable,
	focusNode: _effectiveFocusNode,
	autofocus: widget.autofocus,
	enabled: _enabled,
	builder: (BuildContext context, ToggleableStateMixin state) {
	return _RadioPaint(
	activeColor: widget.activeColor,
	inactiveColor: widget.inactiveColor,
	fillColor: widget.fillColor,
	focusColor: widget.focusColor,
	useCheckmarkStyle: widget.useCheckmarkStyle,
	isActive: _enabled,
	toggleableState: state,
	focused: _effectiveFocusNode.hasFocus,
	);
	},
	);
	}
	}

	/// A registry for deprecated API.
	// TODO(chunhtai): Remove this once deprecated API is removed.
	class _RadioRegistry<T> extends RadioGroupRegistry<T> {
	_RadioRegistry(this.state);
	final _CupertinoRadioState<T> state;
	@override
	T? get groupValue => state.widget.groupValue;

	@override
	ValueChanged<T?> get onChanged => state.widget.onChanged!;

	@override
	void registerClient(RadioClient<T> radio) {}

	@override
	void unregisterClient(RadioClient<T> radio) {}
	}

	class _RadioPaint extends StatefulWidget {
	const _RadioPaint({
	required this.focused,
	required this.toggleableState,
	required this.activeColor,
	required this.inactiveColor,
	required this.fillColor,
	required this.focusColor,
	required this.useCheckmarkStyle,
	required this.isActive,
	});

	final ToggleableStateMixin toggleableState;
	final Color? activeColor;
	final Color? inactiveColor;
	final Color? fillColor;
	final Color? focusColor;
	final bool useCheckmarkStyle;
	final bool isActive;

	final bool focused;
	@override
	State<StatefulWidget> createState() => _RadioPaintState();
	}

	class _RadioPaintState extends State<_RadioPaint> {
	final _RadioPainter _painter = _RadioPainter();

	@override
	void dispose() {
	_painter.dispose();
	super.dispose();
	}

	WidgetStateProperty<Color> get _defaultOuterColor {
	return WidgetStateProperty.resolveWith((Set<WidgetState> states) {
	if (states.contains(WidgetState.disabled)) {
	return CupertinoDynamicColor.resolve(_kDisabledOuterColor, context);
	}
	if (states.contains(WidgetState.selected)) {
	return widget.activeColor ?? CupertinoDynamicColor.resolve(_kDefaultOuterColor, context);
	}
	return widget.inactiveColor ?? CupertinoColors.white;
	});
	}

	WidgetStateProperty<Color> get _defaultInnerColor {
	return WidgetStateProperty.resolveWith((Set<WidgetState> states) {
	if (states.contains(WidgetState.disabled) && states.contains(WidgetState.selected)) {
	return widget.fillColor ?? CupertinoDynamicColor.resolve(_kDisabledInnerColor, context);
	}
	if (states.contains(WidgetState.selected)) {
	return widget.fillColor ?? CupertinoDynamicColor.resolve(_kDefaultInnerColor, context);
	}
	return CupertinoColors.white;
	});
	}

	WidgetStateProperty<Color> get _defaultBorderColor {
	return WidgetStateProperty.resolveWith((Set<WidgetState> states) {
	if ((states.contains(WidgetState.selected) \|\| states.contains(WidgetState.focused)) &&
	!states.contains(WidgetState.disabled)) {
	return CupertinoColors.transparent;
	}
	if (states.contains(WidgetState.disabled)) {
	return CupertinoDynamicColor.resolve(_kDisabledBorderColor, context);
	}
	return CupertinoDynamicColor.resolve(_kDefaultBorderColor, context);
	});
	}

	@override
	Widget build(BuildContext context) {
	// Colors need to be resolved in selected and non selected states separately.
	final Set<WidgetState> activeStates = widget.toggleableState.states..add(WidgetState.selected);
	final Set<WidgetState> inactiveStates = widget.toggleableState.states
	..remove(WidgetState.selected);

	// Since the states getter always makes a new set, make a copy to use
	// throughout the lifecycle of this build method.
	final Set<WidgetState> currentStates = widget.toggleableState.states;

	final Color effectiveActiveColor = _defaultOuterColor.resolve(activeStates);

	final Color effectiveInactiveColor = _defaultOuterColor.resolve(inactiveStates);

	final Color effectiveFocusOverlayColor =
	widget.focusColor ??
	HSLColor.fromColor(effectiveActiveColor.withOpacity(kCupertinoFocusColorOpacity))
	.withLightness(kCupertinoFocusColorBrightness)
	.withSaturation(kCupertinoFocusColorSaturation)
	.toColor();

	final Color effectiveFillColor = _defaultInnerColor.resolve(currentStates);

	final Color effectiveBorderColor = _defaultBorderColor.resolve(currentStates);

	return CustomPaint(
	size: _size,
	painter: _painter
	..position = widget.toggleableState.position
	..reaction = widget.toggleableState.reaction
	..focusColor = effectiveFocusOverlayColor
	..downPosition = widget.toggleableState.downPosition
	..isFocused = widget.focused
	..activeColor = effectiveActiveColor
	..inactiveColor = effectiveInactiveColor
	..fillColor = effectiveFillColor
	..value = widget.toggleableState.value
	..checkmarkStyle = widget.useCheckmarkStyle
	..isActive = widget.isActive
	..borderColor = effectiveBorderColor
	..brightness = CupertinoTheme.of(context).brightness,
	);
	}
	}

	class _RadioPainter extends ToggleablePainter {
	bool? get value => _value;
	bool? _value;
	set value(bool? value) {
	if (_value == value) {
	return;
	}
	_value = value;
	notifyListeners();
	}

	Color get fillColor => _fillColor!;
	Color? _fillColor;
	set fillColor(Color value) {
	if (value == _fillColor) {
	return;
	}
	_fillColor = value;
	notifyListeners();
	}

	bool get checkmarkStyle => _checkmarkStyle;
	bool _checkmarkStyle = false;
	set checkmarkStyle(bool value) {
	if (value == _checkmarkStyle) {
	return;
	}
	_checkmarkStyle = value;
	notifyListeners();
	}

	Brightness? get brightness => _brightness;
	Brightness? _brightness;
	set brightness(Brightness? value) {
	if (_brightness == value) {
	return;
	}
	_brightness = value;
	notifyListeners();
	}

	Color get borderColor => _borderColor!;
	Color? _borderColor;
	set borderColor(Color value) {
	if (_borderColor == value) {
	return;
	}
	_borderColor = value;
	notifyListeners();
	}

	void _drawPressedOverlay(Canvas canvas, Offset center, double radius) {
	final pressedPaint = Paint()
	..color = brightness == Brightness.light
	? CupertinoColors.black.withOpacity(_kPressedOverlayOpacity)
	: CupertinoColors.white.withOpacity(_kPressedOverlayOpacity);
	canvas.drawCircle(center, radius, pressedPaint);
	}

	void _drawFillGradient(
	Canvas canvas,
	Offset center,
	double radius,
	Color topColor,
	Color bottomColor,
	) {
	final fillGradient = LinearGradient(
	begin: Alignment.topCenter,
	end: Alignment.bottomCenter,
	colors: <Color>[topColor, bottomColor],
	);
	final circleRect = Rect.fromCircle(center: center, radius: radius);
	final gradientPaint = Paint()..shader = fillGradient.createShader(circleRect);
	canvas.drawPath(Path()..addOval(circleRect), gradientPaint);
	}

	void _drawOuterBorder(Canvas canvas, Offset center) {
	final borderPaint = Paint()
	..style = PaintingStyle.stroke
	..color = borderColor
	..strokeWidth = _kBorderOutlineStrokeWidth;
	canvas.drawCircle(center, _kOuterRadius, borderPaint);
	}

	@override
	void paint(Canvas canvas, Size size) {
	final Offset center = (Offset.zero & size).center;

	if (checkmarkStyle) {
	if (value ?? false) {
	final path = Path();
	final checkPaint = Paint()
	..color = activeColor
	..style = PaintingStyle.stroke
	..strokeWidth = _kCheckmarkStrokeWidth
	..strokeCap = StrokeCap.round;
	final double width = _size.width;
	final origin = Offset(center.dx - (width / 2), center.dy - (width / 2));
	final start = Offset(width * 0.25, width * 0.52);
	final mid = Offset(width * 0.46, width * 0.75);
	final end = Offset(width * 0.85, width * 0.29);
	path.moveTo(origin.dx + start.dx, origin.dy + start.dy);
	path.lineTo(origin.dx + mid.dx, origin.dy + mid.dy);
	canvas.drawPath(path, checkPaint);
	path.moveTo(origin.dx + mid.dx, origin.dy + mid.dy);
	path.lineTo(origin.dx + end.dx, origin.dy + end.dy);
	canvas.drawPath(path, checkPaint);
	}
	} else {
	if (value ?? false) {
	final outerPaint = Paint()..color = activeColor;
	// Draw a gradient in dark mode if the radio is disabled.
	if (brightness == Brightness.dark && !isActive) {
	_drawFillGradient(
	canvas,
	center,
	_kOuterRadius,
	outerPaint.color.withOpacity(
	isActive ? _kDarkGradientOpacities[0] : _kDisabledDarkGradientOpacities[0],
	),
	outerPaint.color.withOpacity(
	isActive ? _kDarkGradientOpacities[1] : _kDisabledDarkGradientOpacities[1],
	),
	);
	} else {
	canvas.drawCircle(center, _kOuterRadius, outerPaint);
	}
	// The outer circle's opacity changes when the radio is pressed.
	if (downPosition != null) {
	_drawPressedOverlay(canvas, center, _kOuterRadius);
	}
	final innerPaint = Paint()..color = fillColor;
	canvas.drawCircle(center, _kInnerRadius, innerPaint);
	// Draw an outer border if the radio is disabled and selected.
	if (!isActive) {
	_drawOuterBorder(canvas, center);
	}
	} else {
	final paint = Paint();
	paint.color = isActive ? inactiveColor : _kDisabledOuterColor;
	if (brightness == Brightness.dark) {
	_drawFillGradient(
	canvas,
	center,
	_kOuterRadius,
	paint.color.withOpacity(
	isActive ? _kDarkGradientOpacities[0] : _kDisabledDarkGradientOpacities[0],
	),
	paint.color.withOpacity(
	isActive ? _kDarkGradientOpacities[1] : _kDisabledDarkGradientOpacities[1],
	),
	);
	} else {
	canvas.drawCircle(center, _kOuterRadius, paint);
	}
	// The entire circle's opacity changes when the radio is pressed.
	if (downPosition != null) {
	_drawPressedOverlay(canvas, center, _kOuterRadius);
	}
	_drawOuterBorder(canvas, center);
	}
	}
	if (isFocused) {
	final focusPaint = Paint()
	..style = PaintingStyle.stroke
	..color = focusColor
	..strokeWidth = _kFocusOutlineStrokeWidth;
	canvas.drawCircle(center, _kOuterRadius + _kFocusOutlineStrokeWidth / 2, focusPaint);
	}
	}
	}