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. The fillColor in the selected state is used for the selected item's text color. If it is null, the activeColor is used.

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.

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 RadioListTile itself but by the Material widget ancestor. In this case, one can wrap a Material widget around the RadioListTile, e.g.:

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

Performance considerations when wrapping RadioListTile with Material

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

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

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

link

To create a local project with this code sample, run:
flutter create --sample=material.RadioListTile.2 mysample

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.

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

link

To create a local project with this code sample, run:
flutter create --sample=material.RadioListTile.4 mysample

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.

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

link

To create a local project with this code sample, run:
flutter create --sample=material.RadioListTile.5 mysample

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.