RadioButton class

Radio buttons, also called option buttons, let users select one option from a collection of two or more mutually exclusive, but related, options. Radio buttons are always used in groups, and each option is represented by one radio button in the group.

In the default state, no radio button in a RadioButtons group is selected. That is, all radio buttons are cleared. However, once a user has selected a radio button, the user can't deselect the button to restore the group to its initial cleared state.

The singular behavior of a RadioButtons group distinguishes it from check boxes, which support multi-selection and deselection, or clearing.

See also:

• ToggleSwitch
• Checkbox
• ToggleButton

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatelessWidget
• RadioButton

Constructors

RadioButton({Key? key, required bool checked, required ValueChanged<bool>? onChanged, RadioButtonThemeData? style, String? semanticLabel, FocusNode? focusNode, bool autofocus = false})

const

Properties

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 the button is checked of not

final

focusNode → FocusNode?

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

final

hashCode → int

The hash code for this object.

no setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

onChanged → ValueChanged<bool>?

Called when the value of the button is changed. If this is null, the button is considered disabled

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

semanticLabel → String?

Semantic label for the input.

final

style → RadioButtonThemeData?

The style of the button. If non-null, this is merged with ThemeData.radioButtonThemeData

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.

override

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