[Feature Request] Add Status Listener and Animation Status

[gctommy]

I currently have to do something like this to increment an interval when the animation duration reaches/passes the Actor's duration—so do something when the animation completes one loop:

_duration += elapsed * _speed;
// ...
if (double.parse(_duration.toStringAsFixed(2)) >= double.parse(_actor.duration.toStringAsFixed(2))) {
    interval++;
    _duration = 0.0;
}

It would be easier if one could use a controller that has an addStatusListener listening for an AnimationStatus of completed and isAnimating?

[luigi-rosso]

This is a good idea.

On some other platforms we have the concept of AnimationInstance which tracks time for the animation and can report when the animation completes/loops (and has a callback for elapsed events that can trigger on the timeline). We could add something like that which you can use in your FlareController.

Some pseudo-ish code follows...

FlareControls could then return the animationInstance:

AnimationInstance animation = flareControls.play("someAnimation");
animation.onComplete(() { ... });
animation.onLoop(() { ... });

Or what you're suggesting:

class AnimationListener {
  void onLoop(AnimationInstance instance);
  void onComplete(AnimationInstance instance);
  void onMixedIn(AnimationInstance instance);
}
AnimationInstance animation = flareControls.play("someAnimation");
animation.addListener(myListener);

You could also use AnimationInstance directly in a FlareController:

class MyController extends FlareController {
  AnimationInstance someAnimation;
  @override
  void initialize(FlutterActorArtboard artboard) {
    // new artboard method to create an instance
    someAnimation = artboard.getAnimationInstance("someAnimation"); 
  }

  @override
  bool advance(FlutterActorArtboard artboard, double elapsed) {
    super.advance(artboard, elapsed);
    // internally will invoke listeners
    someAnimation.advance(elapsed);
    // apply doesn't need time and mix as the instance holds these internally
    someAnimation.apply(artboard);
  }
}

Curious to hear what people would prefer/find more flexible/fits the platform best.

[stx]

AnimationInstance animation = flareControls.play("someAnimation");
animation.onComplete(() { ... });
animation.onLoop(() { ... });

This feels pretty great with Flutter, IMO.