controller property
final
Defines a default AnimationController for descendant CircularProgressIndicator and LinearProgressIndicator widgets.
If a descendant progress indicator's controller property is null, this
controller will be used to drive its indeterminate animation. This allows
a single controller to synchronize the animations of multiple indicators.
If this property is also null, the progress indicator will create and manage its own internal AnimationController.
Implementation
final AnimationController? controller;