Checkbox class Null safety

A Material Design checkbox.

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

The checkbox can optionally display three values - true, false, and null - if tristate is true. When value is null a dash is displayed. By default tristate is false and the checkbox's value must be true or false.

Requires one of its ancestors to be a Material widget.

This example shows how you can override the default theme of of a Checkbox with a MaterialStateProperty. In this example, the checkbox's color will be Colors.blue when the Checkbox is being pressed, hovered, or focused. Otherwise, the checkbox's color will be Colors.red.
To create a local project with this code sample, run:
flutter create --sample=material.Checkbox.1 mysample

See also:

Inheritance

Constructors

Checkbox({Key? key, required bool? value, bool tristate = false, required ValueChanged<bool?>? onChanged, MouseCursor? mouseCursor, Color? activeColor, MaterialStateProperty<Color?>? fillColor, Color? checkColor, Color? focusColor, Color? hoverColor, MaterialStateProperty<Color?>? overlayColor, double? splashRadius, MaterialTapTargetSize? materialTapTargetSize, VisualDensity? visualDensity, FocusNode? focusNode, bool autofocus = false, OutlinedBorder? shape, BorderSide? side})
Creates a Material Design checkbox.
const

Properties

activeColor Color?
The color to use when this checkbox is checked.
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
checkColor Color?
The color to use for the check icon when this checkbox is checked.
final
fillColor MaterialStateProperty<Color?>?
The color that fills the checkbox, in all MaterialStates.
final
focusColor Color?
The color for the checkbox's Material when it has the input focus.
final
focusNode FocusNode?
An optional focus node to use as the focus node for this widget.
final
hashCode int
The hash code for this object.
@nonVirtual, read-only, inherited
hoverColor Color?
The color for the checkbox's Material when a pointer is hovering over it.
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<bool?>?
Called when the value of the checkbox should change.
final
overlayColor MaterialStateProperty<Color?>?
The color for the checkbox's Material.
final
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited
shape OutlinedBorder?
The shape of the checkbox's Material.
final
side BorderSide?
The color and width of the checkbox's border.
final
splashRadius double?
The splash radius of the circular Material ink response.
final
tristate bool
If true the checkbox's value can be true, false, or null.
final
value bool?
Whether this checkbox is checked.
final
visualDensity VisualDensity?
Defines how compact the checkbox's layout will be.
final

Methods

createElement() StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() State<Checkbox>
Creates the mutable state for this widget at a given location in the tree.
override
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.info}) String
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 ==(Object other) bool
The equality operator.
@nonVirtual, inherited

Constants

width → const double
The width of a checkbox widget.
18.0