FloatingActionButton class

A Material Design floating action button.

A floating action button is a circular icon button that hovers over content to promote a primary action in the application. Floating action buttons are most commonly used in the Scaffold.floatingActionButton field.

Use at most a single floating action button per screen. Floating action buttons should be used for positive actions such as "create", "share", or "navigate". (If more than one floating action button is used within a Route, then make sure that each button has a unique heroTag, otherwise an exception will be thrown.)

If the onPressed callback is null, then the button will be disabled and will not react to touch. It is highly discouraged to disable a floating action button as there is no indication to the user that the button is disabled. Consider changing the backgroundColor if disabling the floating action button.

This example shows a FloatingActionButton in its usual position within a Scaffold. Pressing the button cycles it through a few variations in its foregroundColor, backgroundColor, and shape. The button automatically animates its segue from one set of visual parameters to another.
link

To create a local project with this code sample, run:
flutter create --sample=material.FloatingActionButton.1 mysample

This sample shows all the variants of FloatingActionButton widget as described in: https://m3.material-io.cn/components/floating-action-button/overview.
link

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

This sample shows FloatingActionButton with additional color mappings as described in: https://m3.material-io.cn/components/floating-action-button/overview.
link

To create a local project with this code sample, run:
flutter create --sample=material.FloatingActionButton.3 mysample

See also:

Inheritance

Constructors

FloatingActionButton({Key? key, Widget? child, String? tooltip, Color? foregroundColor, Color? backgroundColor, Color? focusColor, Color? hoverColor, Color? splashColor, Object? heroTag = const _DefaultHeroTag(), double? elevation, double? focusElevation, double? hoverElevation, double? highlightElevation, double? disabledElevation, required VoidCallback? onPressed, MouseCursor? mouseCursor, bool mini = false, ShapeBorder? shape, Clip clipBehavior = Clip.none, FocusNode? focusNode, bool autofocus = false, MaterialTapTargetSize? materialTapTargetSize, bool isExtended = false, bool? enableFeedback})
Creates a circular floating action button.
const
FloatingActionButton.extended({Key? key, String? tooltip, Color? foregroundColor, Color? backgroundColor, Color? focusColor, Color? hoverColor, Object? heroTag = const _DefaultHeroTag(), double? elevation, double? focusElevation, double? hoverElevation, Color? splashColor, double? highlightElevation, double? disabledElevation, required VoidCallback? onPressed, MouseCursor? mouseCursor = SystemMouseCursors.click, ShapeBorder? shape, bool isExtended = true, MaterialTapTargetSize? materialTapTargetSize, Clip clipBehavior = Clip.none, FocusNode? focusNode, bool autofocus = false, double? extendedIconLabelSpacing, EdgeInsetsGeometry? extendedPadding, TextStyle? extendedTextStyle, Widget? icon, required Widget label, bool? enableFeedback})
Creates a wider StadiumBorder-shaped floating action button with an optional icon and a label.
const
FloatingActionButton.large({Key? key, Widget? child, String? tooltip, Color? foregroundColor, Color? backgroundColor, Color? focusColor, Color? hoverColor, Color? splashColor, Object? heroTag = const _DefaultHeroTag(), double? elevation, double? focusElevation, double? hoverElevation, double? highlightElevation, double? disabledElevation, required VoidCallback? onPressed, MouseCursor? mouseCursor, ShapeBorder? shape, Clip clipBehavior = Clip.none, FocusNode? focusNode, bool autofocus = false, MaterialTapTargetSize? materialTapTargetSize, bool? enableFeedback})
Creates a large circular floating action button.
const
FloatingActionButton.small({Key? key, Widget? child, String? tooltip, Color? foregroundColor, Color? backgroundColor, Color? focusColor, Color? hoverColor, Color? splashColor, Object? heroTag = const _DefaultHeroTag(), double? elevation, double? focusElevation, double? hoverElevation, double? highlightElevation, double? disabledElevation, required VoidCallback? onPressed, MouseCursor? mouseCursor, ShapeBorder? shape, Clip clipBehavior = Clip.none, FocusNode? focusNode, bool autofocus = false, MaterialTapTargetSize? materialTapTargetSize, bool? enableFeedback})
Creates a small circular floating action button.
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
backgroundColor → Color?
The button's background color.
final
child → Widget?
The widget below this widget in the tree.
final
clipBehavior → Clip
The content will be clipped (or not) according to this option.
final
disabledElevation → double?
The z-coordinate at which to place this button when the button is disabled (onPressed is null).
final
elevation → double?
The z-coordinate at which to place this button relative to its parent.
final
enableFeedback → bool?
Whether detected gestures should provide acoustic and/or haptic feedback.
final
extendedIconLabelSpacing → double?
The spacing between the icon and the label for an extended FloatingActionButton.
final
extendedPadding → EdgeInsetsGeometry?
The padding for an extended FloatingActionButton's content.
final
extendedTextStyle → TextStyle?
The text style for an extended FloatingActionButton's label.
final
focusColor → Color?
The color to use for filling the button when the button has input focus.
final
focusElevation → double?
The z-coordinate at which to place this button relative to its parent when the button has the input focus.
final
focusNode → FocusNode?
An optional focus node to use as the focus node for this widget.
final
foregroundColor → Color?
The default foreground color for icons and text within the button.
final
hashCode → int
The hash code for this object.
no setterinherited
heroTag → Object?
The tag to apply to the button's Hero widget.
final
highlightElevation → double?
The z-coordinate at which to place this button relative to its parent when the user is touching the button.
final
hoverColor → Color?
The color to use for filling the button when the button has a pointer hovering over it.
final
hoverElevation → double?
The z-coordinate at which to place this button relative to its parent when the button is enabled and has a pointer hovering over it.
final
isExtended → bool
True if this is an "extended" floating action button.
final
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
materialTapTargetSize → MaterialTapTargetSize?
Configures the minimum size of the tap target.
final
mini → bool
Controls the size of this button.
final
mouseCursor → MouseCursor?
The cursor for a mouse pointer when it enters or is hovering over the button.
final
onPressed → VoidCallback?
The callback that is called when the button is tapped or otherwise activated.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
shape → ShapeBorder?
The shape of the button's Material.
final
splashColor → Color?
The splash color for this FloatingActionButton's InkWell.
final
tooltip → String?
Text that describes the action that will occur when the button is pressed.
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}) → 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