LinearProgressIndicator class Null safety

A Material Design linear progress indicator, also known as a progress bar.

A widget that shows progress along a line. There are two kinds of linear progress indicators:

  • Determinate. Determinate progress indicators have a specific value at each point in time, and the value should increase monotonically from 0.0 to 1.0, at which time the indicator is complete. To create a determinate progress indicator, use a non-null value between 0.0 and 1.0.
  • Indeterminate. Indeterminate progress indicators do not have a specific value at each point in time and instead indicate that progress is being made without indicating how much progress remains. To create an indeterminate progress indicator, use a null value.

The indicator line is displayed with valueColor, an animated value. To specify a constant color value use: AlwaysStoppedAnimation<Color>(color).

The minimum height of the indicator can be specified using minHeight. The indicator can be made taller by wrapping the widget with a SizedBox.

This example shows a LinearProgressIndicator with a changing value.
To create a local project with this code sample, run:
flutter create --sample=material.LinearProgressIndicator.1 mysample

See also:



LinearProgressIndicator({Key? key, double? value, Color? backgroundColor, Color? color, Animation<Color?>? valueColor, double? minHeight, String? semanticsLabel, String? semanticsValue})
Creates a linear progress indicator.


backgroundColor Color?
Color of the track being filled by the linear indicator.
read-only, override
color Color?
The progress indicator's color.
final, inherited
hashCode int
The hash code for this object.
@nonVirtual, read-only, inherited
key Key?
Controls how one widget replaces another widget in the tree.
final, inherited
minHeight double?
The minimum height of the line used to draw the linear indicator.
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited
semanticsLabel String?
The SemanticsProperties.label for this progress indicator.
final, inherited
semanticsValue String?
The SemanticsProperties.value for this progress indicator.
final, inherited
value double?
If non-null, the value of this progress indicator.
final, inherited
valueColor Animation<Color?>?
The progress indicator's color as an animated value.
final, inherited


createElement() StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
createState() State<LinearProgressIndicator>
Creates the mutable state for this widget at a given 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 DiagnosticsNode.toStringDeep.
toString({DiagnosticLevel minLevel =}) String
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 ==(Object other) bool
The equality operator.
@nonVirtual, inherited