Radio<T> class

A material design radio button.

Used to select between a number of mutually exclusive values. When one radio button in a group is selected, the other radio buttons in the group cease to be selected. The values are of type T, the type parameter of the Radio class. Enums are commonly used for this purpose.

The radio button itself does not maintain any state. Instead, when the state of the radio button changes, the widget calls the onChanged callback. Most widget that use a radio button will listen for the onChanged callback and rebuild the radio button with a new groupValue to update the visual appearance of the radio button.

Requires one of its ancestors to be a Material widget.

See also:



Radio({Key key, @required T value, @required T groupValue, @required ValueChanged<T> onChanged, Color activeColor })
Creates a material design radio button. [...]


activeColor Color
The color to use when this radio button is selected. [...]
groupValue → T
The currently selected value for this group of radio buttons. [...]
onChanged ValueChanged<T>
Called when the user selects this radio button. [...]
value → T
The value represented by this radio button.
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


createState() → _RadioState<T>
Creates the mutable state for this widget at a given location in the tree. [...]
createElement() StatefulElement
Creates a StatefulElement to manage this widget's location in the tree. [...]
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. [...]
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed. [...]
toDiagnosticsNode({String name, DiagnosticsTreeStyle style }) DiagnosticsNode
Returns a debug representation of the object that is used by debugging tools and by toStringDeep. [...]
toString({DiagnosticLevel minLevel: DiagnosticLevel.debug }) String
Returns a string representation of this object.
toStringDeep({String prefixLineOne: '', String prefixOtherLines, DiagnosticLevel minLevel: DiagnosticLevel.debug }) String
Returns a string representation of this node and its descendants. [...]
toStringShallow({String joiner: ', ', DiagnosticLevel minLevel: DiagnosticLevel.debug }) String
Returns a one-line detailed description of the object. [...]
toStringShort() String
A short, textual description of this widget.


operator ==(dynamic other) bool
The equality operator. [...]