AnimationMixin<T extends StatefulWidget> mixin

Mixin for State classes that host one or more AnimationControllers.

Automatically dispatches AnimationTickMsg to the correct controller and chains the next frame tick if the animation is still running.

Controllers created via createAnimationController are automatically disposed when the State is disposed. Externally created controllers can be registered with registerAnimationController for tick dispatch and automatic disposal.

Usage

class _FadeInState extends State<FadeIn> with AnimationMixin {
  late AnimationController _controller;

  @override
  void initState() {
    super.initState();
    _controller = createAnimationController(
      duration: const Duration(milliseconds: 300),
    );
    _controller.addListener(() => setState(() {}));
  }

  @override
  Cmd? handleInit() => _controller.forward();

  @override
  Widget build(BuildContext context) {
    return Opacity(opacity: _controller.value, child: widget.child);
  }
}

Multiple controllers

You can create as many controllers as you need. Each one gets a unique AnimationController.id so that tick messages are dispatched correctly:

late AnimationController _fadeController;
late AnimationController _slideController;

@override
void initState() {
  super.initState();
  _fadeController = createAnimationController(
    duration: const Duration(milliseconds: 300),
  );
  _slideController = createAnimationController(
    duration: const Duration(milliseconds: 500),
  );
  _fadeController.addListener(() => setState(() {}));
  _slideController.addListener(() => setState(() {}));
}

@override
Cmd? handleInit() {
  return Cmd.batch([
    _fadeController.forward(),
    _slideController.forward(curve: Curves.easeOut),
  ]);
}

Superclass constraints

State<T>

Properties

context ↔ BuildContext: The build context for this state.
getter/setter pairinherited
hashCode → int: The hash code for this object.
no setterinherited
mounted → bool: Whether this state is currently mounted in the element tree.
no setterinherited
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
widget ↔ T: The current configuration for this state.
getter/setter pairinherited

Methods

build(BuildContext context) → Widget: Builds the widget subtree for this state.
inherited
createAnimationController({double? value, Duration? duration, Duration? reverseDuration, double lowerBound = 0.0, double upperBound = 1.0, int fps = 30, Object? id}) → AnimationController: Creates and registers an AnimationController.
didUpdateWidget(covariant T oldWidget) → Cmd?: Called when the widget configuration changes.
inherited
dispose() → void: Disposes all registered controllers and clears the list.
override
handleInit() → Cmd?: Called once when the widget tree is first mounted.
inherited
handleIntercept(Msg msg) → Cmd?: Called before children during message dispatch.
inherited
handleUpdate(Msg msg) → Cmd?: Intercepts AnimationTickMsg and dispatches it to the matching controller via AnimationController.processTick.
override
initState() → void: Called when the state is inserted into the tree.
inherited
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
registerAnimationController(AnimationController controller) → void: Registers an externally-created controller for tick dispatch and automatic disposal.
setState(void fn()) → void: Notifies the framework that this state's internal data has changed.
inherited
toString() → String: A string representation of this object.
inherited
unregisterAnimationController(AnimationController controller) → bool: Unregisters a controller so it no longer receives tick dispatch and is no longer automatically disposed.

Operators

operator ==(Object other) → bool: The equality operator.
inherited