Can't Only Use OnStart to Find StateMachineBehaviours

In short: A MonoBehaviour can't know if its attached anaimator's state machine has created new StateMachineBehaviours just by using its OnStart method.


I started hooking into animation event handling using the new StateMachineBehavriour. But I noticed a bit of an inconsistency from what is explained in this tutorial

By logging from their constructors, I've seen that the AnimationStateBehaviours attached to the state machine get re-instantiated on each awake call for that gameObject. Unfortunately, that's not just on the initial awake call that invokes my MonoBehaviour's "OnStart" method. This means that, if I cache out all of my references to the animator's custom StateMachineBehaviours on "Start" like is recommend in the tutorial then I'm going to miss all states behaviors created after future awake calls.

I've been able to work around this by

• A) Having my monoBehaviour call GetBehaviour on the animator in OnEnable rather than OnStart
  
• B) Having my state object find my attached monoBehaviour using a call to the animator's getComponent method in the state's overrriden events.

Code (CSharp):

1.         public override void OnStateExit(Animator animator, AnimatorStateInfo stateInfo, int layerIndex)
2.         {
3.             CheckInWithControllers(animator);
4.             eventController.HandleAnimationHookExit(stateInfo);
5.         }
6.  
7.         private void CheckInWithControllers(Animator animator)
8.         {
9.             if (!isCheckedIn)
10.             {
11.                 eventController = animator.GetComponent<AnimationEventControllerImpl>();
12.                 isCheckedIn = true;
13.             }
14.         }

But both seem like a pretty ugly work around and I'd rather just be able to avoid all the subsequent GetComponent / GetBehaviour calls by relying on the OnStart method the tutorial mentions.