RadioListTile<T> class

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, but the color used is that described by activeColor, if any, defaulting to the accent color of the current Theme. No effort is made to 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.

RadioListTile sample

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

enum SingingCharacter { lafayette, jefferson }

// ...

SingingCharacter _character = SingingCharacter.lafayette;

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

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.

Radio list tile semantics sample

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

import 'package:flutter/gestures.dart';

// ...

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

  final String label;
  final EdgeInsets padding;
  final bool groupValue;
  final bool value;
  final Function onChanged;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: padding,
      child: Row(
        children: <Widget>[
          Radio<bool>(
            groupValue: groupValue,
            value: value,
            onChanged: (bool newValue) {
              onChanged(newValue);
            }
          ),
          RichText(
            text: TextSpan(
              text: label,
              style: TextStyle(
                color: Colors.blueAccent,
                decoration: TextDecoration.underline,
              ),
              recognizer: TapGestureRecognizer()
                ..onTap = () {
                print('Label has been tapped.');
              },
            ),
          ),
        ],
      ),
    );
  }
}

// ...

bool _isRadioSelected = false;

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

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.

Custom radio list tile sample

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

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

  final String label;
  final EdgeInsets padding;
  final bool groupValue;
  final bool value;
  final Function onChanged;

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

// ...

bool _isRadioSelected = false;

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: Column(
      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;
            });
          },
        ),
      ],
    ),
  );
}

See also:

Inheritance

Constructors

RadioListTile({Key key, @required T value, @required T groupValue, @required ValueChanged<T> onChanged, Color activeColor, Widget title, Widget subtitle, bool isThreeLine: false, bool dense, Widget secondary, bool selected: false, ListTileControlAffinity controlAffinity: ListTileControlAffinity.platform })
Creates a combination of a list tile and a radio button. [...]
const

Properties

activeColor Color
The color to use when this radio button is selected. [...]
final
checked bool
Whether this radio button is checked. [...]
read-only
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
groupValue → T
The currently selected value for this group of radio buttons. [...]
final
isThreeLine bool
Whether this list tile is intended to display three lines of text. [...]
final
onChanged ValueChanged<T>
Called when the user selects this radio button. [...]
final
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
subtitle Widget
Additional content displayed below the title. [...]
final
title Widget
The primary content of the list tile. [...]
final
value → T
The value represented by this radio button.
final
hashCode int
The hash code for this object. [...]
read-only, inherited
key Key
Controls how one widget replaces another widget in the tree. [...]
final, inherited
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited

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. [...]
@protected, inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node. [...]
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent 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.debug }) String
Returns a string representation of this object.
inherited
toStringDeep({String prefixLineOne: '', String prefixOtherLines, DiagnosticLevel minLevel: DiagnosticLevel.debug }) 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 ==(dynamic other) bool
The equality operator. [...]
inherited