packages/flutter/lib/src/material/radio_list_tile.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 'list_tile.dart';
 import 'radio.dart';
 import 'theme.dart';
 import 'theme_data.dart';

 // Examples can assume:
 // void setState(VoidCallback fn) { }

 /// A [ListTile] with a [Radio]. In other words, a radio button with a label.
 ///
 /// The entire list tile is interactive: tapping anywhere in the tile selects
 /// the radio button.
 ///
 /// The [value], [groupValue], [onChanged], and [activeColor] properties of this
 /// widget are identical to the similarly-named properties on the [Radio]
 /// widget. The type parameter `T` serves the same purpose as that of the
 /// [Radio] class' type parameter.
 ///
 /// The [title], [subtitle], [isThreeLine], and [dense] properties are like
 /// those of the same name on [ListTile].
 ///
 /// The [selected] property on this widget is similar to the [ListTile.selected]
 /// property. This tile's [activeColor] is used for the selected item's text color, or
 /// the theme's [ThemeData.toggleableActiveColor] if [activeColor] is null.
 ///
 /// This widget does not coordinate the [selected] state and the
 /// [checked] state; to have the list tile appear selected when the
 /// radio button is the selected radio button, set [selected] to true
 /// when [value] matches [groupValue].
 ///
 /// The radio button is shown on the left by default in left-to-right languages
 /// (i.e. the leading edge). This can be changed using [controlAffinity]. The
 /// [secondary] widget is placed on the opposite side. This maps to the
 /// [ListTile.leading] and [ListTile.trailing] properties of [ListTile].
 ///
 /// To show the [RadioListTile] as disabled, pass null as the [onChanged]
 /// callback.
 ///
 /// {@tool dartpad}
 /// ![RadioListTile sample](https://flutter.github.io/assets-for-api-docs/assets/material/radio_list_tile.png)
 ///
 /// This widget shows a pair of radio buttons that control the `_character`
 /// field. The field is of the type `SingingCharacter`, an enum.
 ///
 /// ** See code in examples/api/lib/material/radio_list_tile/radio_list_tile.0.dart **
 /// {@end-tool}
 ///
 /// ## Semantics in RadioListTile
 ///
 /// Since the entirety of the RadioListTile is interactive, it should represent
 /// itself as a single interactive entity.
 ///
 /// To do so, a RadioListTile widget wraps its children with a [MergeSemantics]
 /// widget. [MergeSemantics] will attempt to merge its descendant [Semantics]
 /// nodes into one node in the semantics tree. Therefore, RadioListTile will
 /// throw an error if any of its children requires its own [Semantics] node.
 ///
 /// For example, you cannot nest a [RichText] widget as a descendant of
 /// RadioListTile. [RichText] has an embedded gesture recognizer that
 /// requires its own [Semantics] node, which directly conflicts with
 /// RadioListTile's desire to merge all its descendants' semantic nodes
 /// into one. Therefore, it may be necessary to create a custom radio tile
 /// widget to accommodate similar use cases.
 ///
 /// {@tool dartpad}
 /// ![Radio list tile semantics sample](https://flutter.github.io/assets-for-api-docs/assets/material/radio_list_tile_semantics.png)
 ///
 /// Here is an example of a custom labeled radio widget, called
 /// LinkedLabelRadio, that includes an interactive [RichText] widget that
 /// handles tap gestures.
 ///
 /// ** See code in examples/api/lib/material/radio_list_tile/radio_list_tile.1.dart **
 /// {@end-tool}
 ///
 /// ## RadioListTile isn't exactly what I want
 ///
 /// If the way RadioListTile pads and positions its elements isn't quite what
 /// you're looking for, you can create custom labeled radio widgets by
 /// combining [Radio] with other widgets, such as [Text], [Padding] and
 /// [InkWell].
 ///
 /// {@tool dartpad}
 /// ![Custom radio list tile sample](https://flutter.github.io/assets-for-api-docs/assets/material/radio_list_tile_custom.png)
 ///
 /// Here is an example of a custom LabeledRadio widget, but you can easily
 /// make your own configurable widget.
 ///
 /// ** See code in examples/api/lib/material/radio_list_tile/radio_list_tile.2.dart **
 /// {@end-tool}
 ///
 /// See also:
 ///
 ///  * [ListTileTheme], which can be used to affect the style of list tiles,
 ///    including radio list tiles.
 ///  * [CheckboxListTile], a similar widget for checkboxes.
 ///  * [SwitchListTile], a similar widget for switches.
 ///  * [ListTile] and [Radio], the widgets from which this widget is made.
 class RadioListTile<T> extends StatelessWidget {
   /// Creates a combination of a list tile and a radio button.
   ///
   /// The radio tile itself does not maintain any state. Instead, when the radio
   /// button is selected, the widget calls the [onChanged] callback. Most
   /// widgets that use a radio button will listen for the [onChanged] callback
   /// and rebuild the radio tile with a new [groupValue] to update the visual
   /// appearance of the 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 RadioListTile({
     Key? key,
     required this.value,
     required this.groupValue,
     required this.onChanged,
     this.toggleable = false,
     this.activeColor,
     this.title,
     this.subtitle,
     this.isThreeLine = false,
     this.dense,
     this.secondary,
     this.selected = false,
     this.controlAffinity = ListTileControlAffinity.platform,
     this.autofocus = false,
     this.contentPadding,
     this.shape,
     this.tileColor,
     this.selectedTileColor,
     this.visualDensity,
     this.focusNode,
     this.enableFeedback,
   }) : assert(toggleable != null),
        assert(isThreeLine != null),
        assert(!isThreeLine || subtitle != null),
        assert(selected != null),
        assert(controlAffinity != null),
        assert(autofocus != null),
        super(key: key);

   /// The value represented by this radio button.
   final T value;

   /// The currently selected value for this group of radio buttons.
   ///
   /// This radio button is considered selected if its [value] matches the
   /// [groupValue].
   final T? groupValue;

   /// Called when the user selects this radio button.
   ///
   /// The radio button passes [value] as a parameter to this callback. The radio
   /// button does not actually change state until the parent widget rebuilds the
   /// radio tile with the new [groupValue].
   ///
   /// If null, the radio button will be displayed as disabled.
   ///
   /// The provided callback will not be invoked if this radio button is already
   /// selected.
   ///
   /// The callback provided to [onChanged] should update the state of the parent
   /// [StatefulWidget] using the [State.setState] method, so that the parent
   /// gets rebuilt; for example:
   ///
   /// ```dart
   /// RadioListTile<SingingCharacter>(
   ///   title: const Text('Lafayette'),
   ///   value: SingingCharacter.lafayette,
   ///   groupValue: _character,
   ///   onChanged: (SingingCharacter newValue) {
   ///     setState(() {
   ///       _character = newValue;
   ///     });
   ///   },
   /// )
   /// ```
   final ValueChanged<T?>? onChanged;

   /// Set to true if this radio list tile is allowed to be returned to an
   /// indeterminate state by selecting it again when selected.
   ///
   /// To indicate returning to an indeterminate state, [onChanged] will be
   /// called with null.
   ///
   /// If true, [onChanged] can be called with [value] when selected while
   /// [groupValue] != [value], or with null when selected again while
   /// [groupValue] == [value].
   ///
   /// If false, [onChanged] will be called with [value] when it is selected
   /// while [groupValue] != [value], and only by selecting another radio button
   /// in the group (i.e. changing the value of [groupValue]) can this radio
   /// list tile be unselected.
   ///
   /// The default is false.
   ///
   /// {@tool dartpad}
   /// This example shows how to enable deselecting a radio button by setting the
   /// [toggleable] attribute.
   ///
   /// ** See code in examples/api/lib/material/radio_list_tile/radio_list_tile.toggleable.0.dart **
   /// {@end-tool}
   final bool toggleable;

   /// The color to use when this radio button is selected.
   ///
   /// Defaults to accent color of the current [Theme].
   final Color? activeColor;

   /// The primary content of the list tile.
   ///
   /// Typically a [Text] widget.
   final Widget? title;

   /// Additional content displayed below the title.
   ///
   /// Typically a [Text] widget.
   final Widget? subtitle;

   /// A widget to display on the opposite side of the tile from the radio button.
   ///
   /// Typically an [Icon] widget.
   final Widget? secondary;

   /// Whether this list tile is intended to display three lines of text.
   ///
   /// If false, the list tile is treated as having one line if the subtitle is
   /// null and treated as having two lines if the subtitle is non-null.
   final bool isThreeLine;

   /// Whether this list tile is part of a vertically dense list.
   ///
   /// If this property is null then its value is based on [ListTileThemeData.dense].
   final bool? dense;

   /// Whether to render icons and text in the [activeColor].
   ///
   /// No effort is made to automatically coordinate the [selected] state and the
   /// [checked] state. To have the list tile appear selected when the radio
   /// button is the selected radio button, set [selected] to true when [value]
   /// matches [groupValue].
   ///
   /// Normally, this property is left to its default value, false.
   final bool selected;

   /// Where to place the control relative to the text.
   final ListTileControlAffinity controlAffinity;

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

   /// Defines the insets surrounding the contents of the tile.
   ///
   /// Insets the [Radio], [title], [subtitle], and [secondary] widgets
   /// in [RadioListTile].
   ///
   /// When null, `EdgeInsets.symmetric(horizontal: 16.0)` is used.
   final EdgeInsetsGeometry? contentPadding;

   /// Whether this radio button is checked.
   ///
   /// To control this value, set [value] and [groupValue] appropriately.
   bool get checked => value == groupValue;

   /// If specified, [shape] defines the shape of the [RadioListTile]'s [InkWell] border.
   final ShapeBorder? shape;

   /// If specified, defines the background color for `RadioListTile` when
   /// [RadioListTile.selected] is false.
   final Color? tileColor;

   /// If non-null, defines the background color when [RadioListTile.selected] is true.
   final Color? selectedTileColor;

   /// Defines how compact the list tile's layout will be.
   ///
   /// {@macro flutter.material.themedata.visualDensity}
   final VisualDensity? visualDensity;

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

   /// {@macro flutter.material.ListTile.enableFeedback}
   ///
   /// See also:
   ///
   ///  * [Feedback] for providing platform-specific feedback to certain actions.
   final bool? enableFeedback;

   @override
   Widget build(BuildContext context) {
     final Widget control = Radio<T>(
       value: value,
       groupValue: groupValue,
       onChanged: onChanged,
       toggleable: toggleable,
       activeColor: activeColor,
       materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
       autofocus: autofocus,
     );
     Widget? leading, trailing;
     switch (controlAffinity) {
       case ListTileControlAffinity.leading:
       case ListTileControlAffinity.platform:
         leading = control;
         trailing = secondary;
         break;
       case ListTileControlAffinity.trailing:
         leading = secondary;
         trailing = control;
         break;
     }
     return MergeSemantics(
       child: ListTileTheme.merge(
         selectedColor: activeColor ?? Theme.of(context).toggleableActiveColor,
         child: ListTile(
           leading: leading,
           title: title,
           subtitle: subtitle,
           trailing: trailing,
           isThreeLine: isThreeLine,
           dense: dense,
           enabled: onChanged != null,
           shape: shape,
           tileColor: tileColor,
           selectedTileColor: selectedTileColor,
           onTap: onChanged != null ? () {
             if (toggleable && checked) {
               onChanged!(null);
               return;
             }
             if (!checked) {
               onChanged!(value);
             }
           } : null,
           selected: selected,
           autofocus: autofocus,
           contentPadding: contentPadding,
           visualDensity: visualDensity,
           focusNode: focusNode,
           enableFeedback: enableFeedback,
         ),
       ),
     );
   }
 }
	// 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 'list_tile.dart';
	import 'radio.dart';
	import 'theme.dart';
	import 'theme_data.dart';

	// Examples can assume:
	// void setState(VoidCallback fn) { }

	/// A [ListTile] with a [Radio]. In other words, a radio button with a label.
	///
	/// The entire list tile is interactive: tapping anywhere in the tile selects
	/// the radio button.
	///
	/// The [value], [groupValue], [onChanged], and [activeColor] properties of this
	/// widget are identical to the similarly-named properties on the [Radio]
	/// widget. The type parameter `T` serves the same purpose as that of the
	/// [Radio] class' type parameter.
	///
	/// The [title], [subtitle], [isThreeLine], and [dense] properties are like
	/// those of the same name on [ListTile].
	///
	/// The [selected] property on this widget is similar to the [ListTile.selected]
	/// property. This tile's [activeColor] is used for the selected item's text color, or
	/// the theme's [ThemeData.toggleableActiveColor] if [activeColor] is null.
	///
	/// This widget does not coordinate the [selected] state and the
	/// [checked] state; to have the list tile appear selected when the
	/// radio button is the selected radio button, set [selected] to true
	/// when [value] matches [groupValue].
	///
	/// The radio button is shown on the left by default in left-to-right languages
	/// (i.e. the leading edge). This can be changed using [controlAffinity]. The
	/// [secondary] widget is placed on the opposite side. This maps to the
	/// [ListTile.leading] and [ListTile.trailing] properties of [ListTile].
	///
	/// To show the [RadioListTile] as disabled, pass null as the [onChanged]
	/// callback.
	///
	/// {@tool dartpad}
	/// ![RadioListTile sample](https://flutter.github.io/assets-for-api-docs/assets/material/radio_list_tile.png)
	///
	/// This widget shows a pair of radio buttons that control the `_character`
	/// field. The field is of the type `SingingCharacter`, an enum.
	///
	/// See code in examples/api/lib/material/radio_list_tile/radio_list_tile.0.dart
	/// {@end-tool}
	///
	/// ## Semantics in RadioListTile
	///
	/// Since the entirety of the RadioListTile is interactive, it should represent
	/// itself as a single interactive entity.
	///
	/// To do so, a RadioListTile widget wraps its children with a [MergeSemantics]
	/// widget. [MergeSemantics] will attempt to merge its descendant [Semantics]
	/// nodes into one node in the semantics tree. Therefore, RadioListTile will
	/// throw an error if any of its children requires its own [Semantics] node.
	///
	/// For example, you cannot nest a [RichText] widget as a descendant of
	/// RadioListTile. [RichText] has an embedded gesture recognizer that
	/// requires its own [Semantics] node, which directly conflicts with
	/// RadioListTile's desire to merge all its descendants' semantic nodes
	/// into one. Therefore, it may be necessary to create a custom radio tile
	/// widget to accommodate similar use cases.
	///
	/// {@tool dartpad}
	/// ![Radio list tile semantics sample](https://flutter.github.io/assets-for-api-docs/assets/material/radio_list_tile_semantics.png)
	///
	/// Here is an example of a custom labeled radio widget, called
	/// LinkedLabelRadio, that includes an interactive [RichText] widget that
	/// handles tap gestures.
	///
	/// See code in examples/api/lib/material/radio_list_tile/radio_list_tile.1.dart
	/// {@end-tool}
	///
	/// ## RadioListTile isn't exactly what I want
	///
	/// If the way RadioListTile pads and positions its elements isn't quite what
	/// you're looking for, you can create custom labeled radio widgets by
	/// combining [Radio] with other widgets, such as [Text], [Padding] and
	/// [InkWell].
	///
	/// {@tool dartpad}
	/// ![Custom radio list tile sample](https://flutter.github.io/assets-for-api-docs/assets/material/radio_list_tile_custom.png)
	///
	/// Here is an example of a custom LabeledRadio widget, but you can easily
	/// make your own configurable widget.
	///
	/// See code in examples/api/lib/material/radio_list_tile/radio_list_tile.2.dart
	/// {@end-tool}
	///
	/// See also:
	///
	/// * [ListTileTheme], which can be used to affect the style of list tiles,
	/// including radio list tiles.
	/// * [CheckboxListTile], a similar widget for checkboxes.
	/// * [SwitchListTile], a similar widget for switches.
	/// * [ListTile] and [Radio], the widgets from which this widget is made.
	class RadioListTile<T> extends StatelessWidget {
	/// Creates a combination of a list tile and a radio button.
	///
	/// The radio tile itself does not maintain any state. Instead, when the radio
	/// button is selected, the widget calls the [onChanged] callback. Most
	/// widgets that use a radio button will listen for the [onChanged] callback
	/// and rebuild the radio tile with a new [groupValue] to update the visual
	/// appearance of the 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 RadioListTile({
	Key? key,
	required this.value,
	required this.groupValue,
	required this.onChanged,
	this.toggleable = false,
	this.activeColor,
	this.title,
	this.subtitle,
	this.isThreeLine = false,
	this.dense,
	this.secondary,
	this.selected = false,
	this.controlAffinity = ListTileControlAffinity.platform,
	this.autofocus = false,
	this.contentPadding,
	this.shape,
	this.tileColor,
	this.selectedTileColor,
	this.visualDensity,
	this.focusNode,
	this.enableFeedback,
	}) : assert(toggleable != null),
	assert(isThreeLine != null),
	assert(!isThreeLine \|\| subtitle != null),
	assert(selected != null),
	assert(controlAffinity != null),
	assert(autofocus != null),
	super(key: key);

	/// The value represented by this radio button.
	final T value;

	/// The currently selected value for this group of radio buttons.
	///
	/// This radio button is considered selected if its [value] matches the
	/// [groupValue].
	final T? groupValue;

	/// Called when the user selects this radio button.
	///
	/// The radio button passes [value] as a parameter to this callback. The radio
	/// button does not actually change state until the parent widget rebuilds the
	/// radio tile with the new [groupValue].
	///
	/// If null, the radio button will be displayed as disabled.
	///
	/// The provided callback will not be invoked if this radio button is already
	/// selected.
	///
	/// The callback provided to [onChanged] should update the state of the parent
	/// [StatefulWidget] using the [State.setState] method, so that the parent
	/// gets rebuilt; for example:
	///
	/// ```dart
	/// RadioListTile<SingingCharacter>(
	/// title: const Text('Lafayette'),
	/// value: SingingCharacter.lafayette,
	/// groupValue: _character,
	/// onChanged: (SingingCharacter newValue) {
	/// setState(() {
	/// _character = newValue;
	/// });
	/// },
	/// )
	/// ```
	final ValueChanged<T?>? onChanged;

	/// Set to true if this radio list tile is allowed to be returned to an
	/// indeterminate state by selecting it again when selected.
	///
	/// To indicate returning to an indeterminate state, [onChanged] will be
	/// called with null.
	///
	/// If true, [onChanged] can be called with [value] when selected while
	/// [groupValue] != [value], or with null when selected again while
	/// [groupValue] == [value].
	///
	/// If false, [onChanged] will be called with [value] when it is selected
	/// while [groupValue] != [value], and only by selecting another radio button
	/// in the group (i.e. changing the value of [groupValue]) can this radio
	/// list tile be unselected.
	///
	/// The default is false.
	///
	/// {@tool dartpad}
	/// This example shows how to enable deselecting a radio button by setting the
	/// [toggleable] attribute.
	///
	/// See code in examples/api/lib/material/radio_list_tile/radio_list_tile.toggleable.0.dart
	/// {@end-tool}
	final bool toggleable;

	/// The color to use when this radio button is selected.
	///
	/// Defaults to accent color of the current [Theme].
	final Color? activeColor;

	/// The primary content of the list tile.
	///
	/// Typically a [Text] widget.
	final Widget? title;

	/// Additional content displayed below the title.
	///
	/// Typically a [Text] widget.
	final Widget? subtitle;

	/// A widget to display on the opposite side of the tile from the radio button.
	///
	/// Typically an [Icon] widget.
	final Widget? secondary;

	/// Whether this list tile is intended to display three lines of text.
	///
	/// If false, the list tile is treated as having one line if the subtitle is
	/// null and treated as having two lines if the subtitle is non-null.
	final bool isThreeLine;

	/// Whether this list tile is part of a vertically dense list.
	///
	/// If this property is null then its value is based on [ListTileThemeData.dense].
	final bool? dense;

	/// Whether to render icons and text in the [activeColor].
	///
	/// No effort is made to automatically coordinate the [selected] state and the
	/// [checked] state. To have the list tile appear selected when the radio
	/// button is the selected radio button, set [selected] to true when [value]
	/// matches [groupValue].
	///
	/// Normally, this property is left to its default value, false.
	final bool selected;

	/// Where to place the control relative to the text.
	final ListTileControlAffinity controlAffinity;

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

	/// Defines the insets surrounding the contents of the tile.
	///
	/// Insets the [Radio], [title], [subtitle], and [secondary] widgets
	/// in [RadioListTile].
	///
	/// When null, `EdgeInsets.symmetric(horizontal: 16.0)` is used.
	final EdgeInsetsGeometry? contentPadding;

	/// Whether this radio button is checked.
	///
	/// To control this value, set [value] and [groupValue] appropriately.
	bool get checked => value == groupValue;

	/// If specified, [shape] defines the shape of the [RadioListTile]'s [InkWell] border.
	final ShapeBorder? shape;

	/// If specified, defines the background color for `RadioListTile` when
	/// [RadioListTile.selected] is false.
	final Color? tileColor;

	/// If non-null, defines the background color when [RadioListTile.selected] is true.
	final Color? selectedTileColor;

	/// Defines how compact the list tile's layout will be.
	///
	/// {@macro flutter.material.themedata.visualDensity}
	final VisualDensity? visualDensity;

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

	/// {@macro flutter.material.ListTile.enableFeedback}
	///
	/// See also:
	///
	/// * [Feedback] for providing platform-specific feedback to certain actions.
	final bool? enableFeedback;

	@override
	Widget build(BuildContext context) {
	final Widget control = Radio<T>(
	value: value,
	groupValue: groupValue,
	onChanged: onChanged,
	toggleable: toggleable,
	activeColor: activeColor,
	materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
	autofocus: autofocus,
	);
	Widget? leading, trailing;
	switch (controlAffinity) {
	case ListTileControlAffinity.leading:
	case ListTileControlAffinity.platform:
	leading = control;
	trailing = secondary;
	break;
	case ListTileControlAffinity.trailing:
	leading = secondary;
	trailing = control;
	break;
	}
	return MergeSemantics(
	child: ListTileTheme.merge(
	selectedColor: activeColor ?? Theme.of(context).toggleableActiveColor,
	child: ListTile(
	leading: leading,
	title: title,
	subtitle: subtitle,
	trailing: trailing,
	isThreeLine: isThreeLine,
	dense: dense,
	enabled: onChanged != null,
	shape: shape,
	tileColor: tileColor,
	selectedTileColor: selectedTileColor,
	onTap: onChanged != null ? () {
	if (toggleable && checked) {
	onChanged!(null);
	return;
	}
	if (!checked) {
	onChanged!(value);
	}
	} : null,
	selected: selected,
	autofocus: autofocus,
	contentPadding: contentPadding,
	visualDensity: visualDensity,
	focusNode: focusNode,
	enableFeedback: enableFeedback,
	),
	),
	);
	}
	}