MongolRadioListTile<T> class

A MongolListTile 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 MongolListTile.

The selected property on this widget is similar to the MongolListTile.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 MongolListTile.leading and MongolListTile.trailing properties of MongolListTile.

This widget requires a Material widget ancestor in the tree to paint itself on, which is typically provided by the app's Scaffold. The tileColor, and selectedTileColor are not painted by the MongolRadioListTile itself but by the Material widget ancestor. In this case, one can wrap a Material widget around the MongolRadioListTile, e.g.:

{@tool snippet}

ColoredBox(
  color: Colors.green,
  child: Material(
    child: MongolRadioListTile<Meridiem>(
      tileColor: Colors.red,
      title: const MongolText('AM'),
      groupValue: Meridiem.am,
      value: Meridiem.am,
      onChanged:(Meridiem? value) { },
    ),
  ),
)

{@end-tool}

Performance considerations when wrapping MongolRadioListTile with Material

Wrapping a large number of MongolRadioListTiles individually with Materials is expensive. Consider only wrapping the MongolRadioListTiles that require it or include a common Material ancestor where possible.

To show the MongolRadioListTile as disabled, pass null as the onChanged callback.

{@tool dartpad}

This widget shows a pair of radio buttons that control the _character field. The field is of the type SingingCharacter, an enum.

import 'package:flutter/material.dart';

/// Flutter code sample for [MongolRadioListTile].

void main() => runApp(const RadioListTileApp());

class RadioListTileApp extends StatelessWidget {
  const RadioListTileApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(useMaterial3: true),
      home: Scaffold(
        appBar: AppBar(title: const Text('RadioListTile Sample')),
        body: const RadioListTileExample(),
      ),
    );
  }
}

enum SingingCharacter { lafayette, jefferson }

class RadioListTileExample extends StatefulWidget {
  const RadioListTileExample({super.key});

  @override
  State<RadioListTileExample> createState() => _RadioListTileExampleState();
}

class _RadioListTileExampleState extends State<RadioListTileExample> {
  SingingCharacter? _character = SingingCharacter.lafayette;

  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        MongolRadioListTile<SingingCharacter>(
          title: const MongolText('Lafayette'),
          value: SingingCharacter.lafayette,
          groupValue: _character,
          onChanged: (SingingCharacter? value) {
            setState(() {
              _character = value;
            });
          },
        ),
        MongolRadioListTile<SingingCharacter>(
          title: const MongolText('Thomas Jefferson'),
          value: SingingCharacter.jefferson,
          groupValue: _character,
          onChanged: (SingingCharacter? value) {
            setState(() {
              _character = value;
            });
          },
        ),
      ],
    );
  }
}

{@end-tool}

{@tool dartpad} This sample demonstrates how MongolRadioListTile positions the radio widget relative to the text in different configurations.

import 'package:flutter/material.dart';

Flutter code sample for [MongolRadioListTile].

void main() => runApp(const RadioListTileApp());

class RadioListTileApp extends StatelessWidget {
  const RadioListTileApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(useMaterial3: true),
      home: const RadioListTileExample(),
    );
  }
}

enum Groceries { pickles, tomato, lettuce }

class RadioListTileExample extends StatefulWidget {
  const RadioListTileExample({super.key});

  @override
  State<RadioListTileExample> createState() => _RadioListTileExampleState();
}

class _RadioListTileExampleState extends State<RadioListTileExample> {
  Groceries? _groceryItem = Groceries.pickles;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('RadioListTile Sample')),
      body: Column(
        children: <Widget>[
          MongolRadioListTile<Groceries>(
            value: Groceries.pickles,
            groupValue: _groceryItem,
            onChanged: (Groceries? value) {
              setState(() {
                _groceryItem = value;
              });
            },
            title: const MongolText('Pickles'),
            subtitle: const MongolText('Supporting text'),
          ),
          MongolRadioListTile<Groceries>(
            value: Groceries.tomato,
            groupValue: _groceryItem,
            onChanged: (Groceries? value) {
              setState(() {
                _groceryItem = value;
              });
            },
            title: const MongolText('Tomato'),
            subtitle: const MongolText(
                'Longer supporting text to demonstrate how the text wraps and the radio is centered vertically with the text.'),
          ),
          MongolRadioListTile<Groceries>(
            value: Groceries.lettuce,
            groupValue: _groceryItem,
            onChanged: (Groceries? value) {
              setState(() {
                _groceryItem = value;
              });
            },
            title: const MongolText('Lettuce'),
            subtitle: const MongolText(
                "Longer supporting text to demonstrate how the text wraps and how setting 'RadioListTile.isThreeLine = true' aligns the radio to the top vertically with the text."),
            isThreeLine: true,
          ),
        ],
      ),
    );
  }
}

{@end-tool}

Semantics in MongolRadioListTile

Since the entirety of the MongolRadioListTile is interactive, it should represent itself as a single interactive entity.

To do so, a MongolRadioListTile 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, MongolRadioListTile will throw an error if any of its children requires its own Semantics node.

For example, you cannot nest a MongolRichText widget as a descendant of MongolRadioListTile. MongolRichText has an embedded gesture recognizer that requires its own Semantics node, which directly conflicts with MongolRadioListTile'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}

Here is an example of a custom labeled radio widget, called LinkedLabelRadio, that includes an interactive MongolRichText widget that handles tap gestures.

import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';

Flutter code sample for custom labeled radio.

void main() => runApp(const LabeledRadioApp());

class LabeledRadioApp extends StatelessWidget {
  const LabeledRadioApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(useMaterial3: true),
      home: Scaffold(
        appBar: AppBar(title: const Text('Custom Labeled Radio Sample')),
        body: const LabeledRadioExample(),
      ),
    );
  }
}

class LinkedLabelRadio extends StatelessWidget {
  const LinkedLabelRadio({
    super.key,
    required this.label,
    required this.padding,
    required this.groupValue,
    required this.value,
    required this.onChanged,
  });

  final String label;
  final EdgeInsets padding;
  final bool groupValue;
  final bool value;
  final ValueChanged<bool> onChanged;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: padding,
      child: Column(
        children: <Widget>[
          Radio<bool>(
            groupValue: groupValue,
            value: value,
            onChanged: (bool? newValue) {
              onChanged(newValue!);
            },
          ),
          MongolRichText(
            text: TextSpan(
              text: label,
              style: TextStyle(
                color: Theme.of(context).colorScheme.primary,
                decoration: TextDecoration.underline,
              ),
              recognizer: TapGestureRecognizer()
                ..onTap = () {
                  debugPrint('Label has been tapped.');
                },
            ),
          ),
        ],
      ),
    );
  }
}

class LabeledRadioExample extends StatefulWidget {
  const LabeledRadioExample({super.key});

  @override
  State<LabeledRadioExample> createState() => _LabeledRadioExampleState();
}

class _LabeledRadioExampleState extends State<LabeledRadioExample> {
  bool _isRadioSelected = false;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Row(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          LinkedLabelRadio(
            label: 'First tappable label text',
            padding: const EdgeInsets.symmetric(horizontal: 5.0),
            value: true,
            groupValue: _isRadioSelected,
            onChanged: (bool newValue) {
              setState(() {
                _isRadioSelected = newValue;
              });
            },
          ),
          LinkedLabelRadio(
            label: 'Second tappable label text',
            padding: const EdgeInsets.symmetric(horizontal: 5.0),
            value: false,
            groupValue: _isRadioSelected,
            onChanged: (bool newValue) {
              setState(() {
                _isRadioSelected = newValue;
              });
            },
          ),
        ],
      ),
    );
  }
}

{@end-tool}

MongolRadioListTile isn't exactly what I want

If the way MongolRadioListTile 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 MongolText, Padding and InkWell.

{@tool dartpad}

Here is an example of a custom LabeledRadio widget, but you can easily make your own configurable widget.

import 'package:flutter/material.dart';

/// Flutter code sample for custom labeled radio.

void main() => runApp(const LabeledRadioApp());

class LabeledRadioApp extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(useMaterial3: true),
      home: Scaffold(
        appBar: AppBar(title: const Text('Custom Labeled Radio Sample')),
        body: const LabeledRadioExample(),
      ),
    );
  }
}

class LabeledRadio extends StatelessWidget {
  const LabeledRadio({
    super.key,
    required this.label,
    required this.padding,
    required this.groupValue,
    required this.value,
    required this.onChanged,
  });

  final String label;
  final EdgeInsets padding;
  final bool groupValue;
  final bool value;
  final ValueChanged<bool> onChanged;

  @override
  Widget build(BuildContext context) {
    return InkWell(
      onTap: () {
        if (value != groupValue) {
          onChanged(value);
        }
      },
      child: Padding(
        padding: padding,
        child: Column(
          children: <Widget>[
            Radio<bool>(
              groupValue: groupValue,
              value: value,
              onChanged: (bool? newValue) {
                onChanged(newValue!);
              },
            ),
            MongolText(label),
          ],
        ),
      ),
    );
  }
}

class LabeledRadioExample extends StatefulWidget {
  const LabeledRadioExample({super.key});

  @override
  State<LabeledRadioExample> createState() => _LabeledRadioExampleState();
}

class _LabeledRadioExampleState extends State<LabeledRadioExample> {
  bool _isRadioSelected = false;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Row(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <LabeledRadio>[
          LabeledRadio(
            label: 'This is the first label text',
            padding: const EdgeInsets.symmetric(horizontal: 5.0),
            value: true,
            groupValue: _isRadioSelected,
            onChanged: (bool newValue) {
              setState(() {
                _isRadioSelected = newValue;
              });
            },
          ),
          LabeledRadio(
            label: 'This is the second label text',
            padding: const EdgeInsets.symmetric(horizontal: 5.0),
            value: false,
            groupValue: _isRadioSelected,
            onChanged: (bool newValue) {
              setState(() {
                _isRadioSelected = newValue;
              });
            },
          ),
        ],
      ),
    );
  }
}

{@end-tool}

See also:

• MongolListTileTheme, which can be used to affect the style of list tiles, including radio list tiles.
• MongolCheckboxListTile, a similar widget for checkboxes.
• MongolSwitchListTile, a similar widget for switches.
• MongolListTile and Radio, the widgets from which this widget is made.

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• MongolRadioListTile

Constructors

MongolRadioListTile.new({Key? key, required T value, required T? groupValue, required ValueChanged<T?>? onChanged, MouseCursor? mouseCursor, bool toggleable = false, Color? activeColor, WidgetStateProperty<Color?>? fillColor, Color? hoverColor, WidgetStateProperty<Color?>? overlayColor, double? splashRadius, MaterialTapTargetSize? materialTapTargetSize, Widget? title, Widget? subtitle, bool isThreeLine = false, bool? dense, Widget? secondary, bool selected = false, ListTileControlAffinity controlAffinity = ListTileControlAffinity.platform, bool autofocus = false, EdgeInsetsGeometry? contentPadding, ShapeBorder? shape, Color? tileColor, Color? selectedTileColor, VisualDensity? visualDensity, FocusNode? focusNode, ValueChanged<bool>? onFocusChange, bool? enableFeedback})

Creates a combination of a list tile and a radio button.

const

MongolRadioListTile.adaptive({Key? key, required T value, required T? groupValue, required ValueChanged<T?>? onChanged, MouseCursor? mouseCursor, bool toggleable = false, Color? activeColor, WidgetStateProperty<Color?>? fillColor, Color? hoverColor, WidgetStateProperty<Color?>? overlayColor, double? splashRadius, MaterialTapTargetSize? materialTapTargetSize, Widget? title, Widget? subtitle, bool isThreeLine = false, bool? dense, Widget? secondary, bool selected = false, ListTileControlAffinity controlAffinity = ListTileControlAffinity.platform, bool autofocus = false, EdgeInsetsGeometry? contentPadding, ShapeBorder? shape, Color? tileColor, Color? selectedTileColor, VisualDensity? visualDensity, FocusNode? focusNode, ValueChanged<bool>? onFocusChange, bool? enableFeedback, bool useCupertinoCheckmarkStyle = false})

Creates a combination of a list tile and a platform adaptive radio.

const

Properties

activeColor → Color?

The color to use when this radio button is selected.

final

autofocus → bool

True if this widget will be selected as the initial focus when no other node in its scope is currently focused.

final

checked → bool

Whether this radio button is checked.

no setter

contentPadding → EdgeInsetsGeometry?

Defines the insets surrounding the contents of the tile.

final

controlAffinity → ListTileControlAffinity

Where to place the control relative to the text.

final

dense → bool?

Whether this list tile is part of a vertically dense list.

final

enableFeedback → bool?

Whether detected gestures should provide acoustic and/or haptic feedback.

final

fillColor → WidgetStateProperty<Color?>?

The color that fills the radio button.

final

focusNode → FocusNode?

An optional focus node to use as the focus node for this widget.

final

groupValue → T?

The currently selected value for this group of radio buttons.

final

hashCode → int

The hash code for this object.

no setter, inherited

hoverColor → Color?

The color for the radio's Material when a pointer is hovering over it.

final

isThreeLine → bool

Whether this list tile is intended to display three lines of text.

final

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

materialTapTargetSize → MaterialTapTargetSize?

Configures the minimum size of the tap target.

final

mouseCursor → MouseCursor?

The cursor for a mouse pointer when it enters or is hovering over the widget.

final

onChanged → ValueChanged<T?>?

Called when the user selects this radio button.

final

onFocusChange → ValueChanged<bool>?

Handler called when the focus changes.

final

overlayColor → WidgetStateProperty<Color?>?

The color for the radio's Material.

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

secondary → Widget?

A widget to display on the opposite side of the tile from the radio button.

final

selected → bool

Whether to render icons and text in the activeColor.

final

selectedTileColor → Color?

If non-null, defines the background color when RadioListTile.selected is true.

final

shape → ShapeBorder?

If specified, shape defines the shape of the RadioListTile's InkWell border.

final

splashRadius → double?

The splash radius of the circular Material ink response.

final

subtitle → Widget?

Additional content displayed below the title.

final

tileColor → Color?

If specified, defines the background color for RadioListTile when RadioListTile.selected is false.

final

title → Widget?

The primary content of the list tile.

final

toggleable → bool

Set to true if this radio list tile is allowed to be returned to an indeterminate state by selecting it again when selected.

final

useCupertinoCheckmarkStyle → bool

Whether to use the checkbox style for the CupertinoRadio control.

final

value → T

The value represented by this radio button.

final

visualDensity → VisualDensity?

Defines how compact the list tile's layout will be.

final

Methods

build(BuildContext context) → Widget

Describes the part of the user interface represented by this widget.

override

createElement() → StatelessElement

Creates a StatelessElement to manage this widget's location in the tree.

inherited

debugDescribeChildren() → List<DiagnosticsNode>

Returns a list of DiagnosticsNode objects describing this node's children.

inherited

debugFillProperties(DiagnosticPropertiesBuilder properties) → void

Add additional properties associated with the node.

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode

Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.

inherited

toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String

A string representation of this object.

inherited

toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug, int wrapWidth = 65}) → String

Returns a string representation of this node and its descendants.

inherited

toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String

Returns a one-line detailed description of the object.

inherited

toStringShort() → String

A short, textual description of this widget.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited