ExpandingTwoHalvesArcLoader class

A custom Flutter widget that displays a rotating loading indicator with two expanding arcs in contrasting colors.

The ExpandingTwoHalvesArcLoader widget animates two arcs that rotate continuously while expanding and contracting to create a dynamic loading effect. The widget supports customizable properties for size, stroke width, colors, rotation speed, and expansion speed.

Key properties include:

  • size: The diameter of the loader in logical pixels.
  • strokeWidth: The width of each arc's stroke, which should be less than one-third of the size.
  • color1 and color2: Colors for each of the two arcs.
  • rotationDurationMs: Duration of one full rotation cycle in milliseconds (minimum of 500).
  • expansionDurationMs: Duration of one full expansion and contraction cycle in milliseconds (minimum of 500).

This widget uses two AnimationControllers:

  • One for the rotation animation, which rotates the arcs indefinitely.
  • One for the expansion animation, which expands and contracts the arcs in a repeating pattern.

The DualArcPainter class is used to paint the arcs onto the canvas, where each arc's angle and sweep are controlled by the expansion value.

Usage example:

ExpandingTwoHalvesArcLoader(
  size: 48.0,
  strokeWidth: 5.0,
  color1: Colors.blue,
  color2: Colors.red,
  rotationDurationMs: 1000,
  expansionDurationMs: 2000,
)
Inheritance

Constructors

ExpandingTwoHalvesArcLoader({Key? key, double size = 48.0, double strokeWidth = 5.0, Color color1 = Colors.blue, Color color2 = Colors.red, int rotationDurationMs = 1000, int expansionDurationMs = 2000})
const

Properties

color1 → Color
final
color2 → Color
final
expansionDurationMs → int
final
hashCode → int
The hash code for this object.
no setterinherited
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
rotationDurationMs → int
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
size → double
final
strokeWidth → double
final

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<ExpandingTwoHalvesArcLoader>
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.
inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node.
inherited
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, int wrapWidth = 65}) → 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