Unity —— Animator 状态机事件通知（Animator 1-2）

一. 状态机监听

1. AnimStateHook - 状态机钩子

• 继承自 Unity 的 StateMachineBehaviour，附加到 Animator Controller 的状态上
• 拦截 Animator 的三个生命周期回调：OnAnimEnter、OnAnimUpdate、OnAnimExit
• 从 Animator 所在 GameObject 获取 AnimEventDispatcher 组件并转发事件

public class AnimStateHook : StateMachineBehaviour
{
    public override void OnStateEnter(Animator animator, AnimatorStateInfo stateInfo, int layerIndex, AnimatorControllerPlayable controller)
    {
        AnimEventDispatcher call = animator.gameObject.GetComponent<AnimEventDispatcher>();
        if (call != null)
        {
            call.OnEnterChannel(animator, stateInfo, layerIndex);
        }
    }

    public override void OnStateUpdate(Animator animator, AnimatorStateInfo stateInfo, int layerIndex, AnimatorControllerPlayable controller)
    {
        AnimEventDispatcher call = animator.gameObject.GetComponent<AnimEventDispatcher>();
        if (call != null)
        {
            call.OnUpdateChannel(animator, stateInfo, layerIndex);
        }
    }

    public override void OnStateExit(Animator animator, AnimatorStateInfo stateInfo, int layerIndex, AnimatorControllerPlayable controller)
    {
        AnimEventDispatcher call = animator.gameObject.GetComponent<AnimEventDispatcher>();
        if (call != null)
        {
            call.OnExitChannel(animator, stateInfo, layerIndex);
        }
    }
}

2. AnimEventDispatcher - 事件分发器

• 作为 MonoBehaviour 组件挂载在有 Animator 的 GameObject 上， 提供外部监听方法
• 接收 AnimStateHook 的回调并广播对应事件

public class AnimEventDispatcher : MonoBehaviour
{
    public Action<int, float> OnEnterEvent;
    public Action<int, float> OnUpdateEvent;
    public Action<int, float> OnExitEvent;


    public void OnEnterChannel(Animator animator, AnimatorStateInfo stateInfo, int layerIndex)
    {
        OnEnterEvent?.Invoke(stateInfo.shortNameHash, stateInfo.normalizedTime);
    }

    public void OnUpdateChannel(Animator animator, AnimatorStateInfo stateInfo, int layerIndex)
    {
        OnUpdateEvent?.Invoke(stateInfo.shortNameHash, stateInfo.normalizedTime);
    }

    public void OnExitChannel(Animator animator, AnimatorStateInfo stateInfo, int layerIndex)
    {
        OnExitEvent?.Invoke(stateInfo.shortNameHash, stateInfo.normalizedTime);
    }
}

3. 总结： 如上提供了一种监听Animator状态变化的监听方法， 入状态进入（Enter）， 状态Update（Update）， 状态退出（Exit）注意事项

• normalizedTime为百分比时间
• 两个相邻状态A -> B， Unity无法保证A的退出先执行， B的进入后执行， 可能先执行B的进入，再执行A的退出也未可知