Slider class

A Material Design slider.

Used to select from a range of values.

A slider can be used to select from either a continuous or a discrete set of values. The default is to use a continuous range of values from min to max. To use discrete values, use a non-null value for divisions, which indicates the number of discrete intervals. For example, if min is 0.0 and max is 50.0 and divisions is 5, then the slider can take on the discrete values 0.0, 10.0, 20.0, 30.0, 40.0, and 50.0.

The terms for the parts of a slider are:

  • The "thumb", which is a shape that slides horizontally when the user drags it.
  • The "track", which is the line that the slider thumb slides along.
  • The "value indicator", which is a shape that pops up when the user is dragging the thumb to indicate the value being selected.
  • The "active" side of the slider is the side between the thumb and the minimum value.
  • The "inactive" side of the slider is the side between the thumb and the maximum value.

The slider will be disabled if onChanged is null or if the range given by min..max is empty (i.e. if min is equal to max).

The slider widget itself does not maintain any state. Instead, when the state of the slider changes, the widget calls the onChanged callback. Most widgets that use a slider will listen for the onChanged callback and rebuild the slider with a new value to update the visual appearance of the slider. To know when the value starts to change, or when it is done changing, set the optional callbacks onChangeStart and/or onChangeEnd.

By default, a slider will be as wide as possible, centered vertically. When given unbounded constraints, it will attempt to make the track 144 pixels wide (with margins on each side) and will shrink-wrap vertically.

Requires one of its ancestors to be a Material widget.

Requires one of its ancestors to be a MediaQuery widget. Typically, these are introduced by the MaterialApp or WidgetsApp widget at the top of your application widget tree.

To determine how it should be displayed (e.g. colors, thumb shape, etc.), a slider uses the SliderThemeData available from either a SliderTheme widget or the ThemeData.sliderTheme a Theme widget above it in the widget tree. You can also override some of the colors with the activeColor and inactiveColor properties, although more fine-grained control of the look is achieved using a SliderThemeData.

See also:



Slider({Key key, @required double value, @required ValueChanged<double> onChanged, ValueChanged<double> onChangeStart, ValueChanged<double> onChangeEnd, double min: 0.0, double max: 1.0, int divisions, String label, Color activeColor, Color inactiveColor, SemanticFormatterCallback semanticFormatterCallback })
Creates a material design slider. [...]


activeColor Color
The color to use for the portion of the slider track that is active. [...]
divisions int
The number of discrete divisions. [...]
inactiveColor Color
The color for the inactive portion of the slider track. [...]
label String
A label to show above the slider when the slider is active. [...]
max double
The maximum value the user can select. [...]
min double
The minimum value the user can select. [...]
onChanged ValueChanged<double>
Called during a drag when the user is selecting a new value for the slider by dragging. [...]
onChangeEnd ValueChanged<double>
Called when the user is done selecting a new value for the slider. [...]
onChangeStart ValueChanged<double>
Called when the user starts selecting a new value for the slider. [...]
semanticFormatterCallback SemanticFormatterCallback
The callback used to create a semantic value from a slider value. [...]
value double
The currently selected value for this slider. [...]
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() → _SliderState
Creates the mutable state for this widget at a given location in the tree. [...]
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node. [...]
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
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 DiagnosticsNode.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. [...]