Unity，协程无法启动

Question

I have a simple finite state machine written by me. I have transitions and states. Here's what StateTransition looks like from inside:

////////////////////////////////////////////////////////////////////////////

public delegate void ActionCaller(IEnumerator action); // Take note of this delegate

private readonly ActionCaller caller;
private readonly IEnumerator action; // This is my State action

////////////////////////////////////////////////////////////////////////////

public void Execute()
{
    caller.Invoke(action); // Here I call my `action` through `caller`
}

////////////////////////////////////////////////////////////////////////////

And here's my MonoBehaviour code which creates this states:

////////////////////////////////////////////////////////////////////////////
private void Start()
{
    // Here I initialize my states and pass a method which will be called in `StateTransition.Execute` to execute passed method and `CallAction` to start Coroutine in my `MonoBehaviour` class
    States = new Dictionary<State, StateTransition>()
    {
        { State.Idling, new StateTransition(State.Idling, DoNothing(), CallAction) },
        { State.WanderingAround, new StateTransition(State.WanderingAround, WanderAround(), CallAction) }
    };

    StateMachine = new FiniteStateMachine(new List<Transition>()
    {
        new Transition(States[State.Idling], States[State.WanderingAround], Input.Wandering),
        new Transition(States[State.WanderingAround], States[State.Idling], Input.Nothing)
    });

    StateMachine.NextState(Input.Wandering);
}

////////////////////////////////////////////////////////////////////////////

private void CallAction(IEnumerator routine)
{
    if (currentActionCoroutine != null)
    {
        StopCoroutine(currentActionCoroutine);
    }

    currentActionCoroutine = StartCoroutine(routine); // This code right here starts my passed `routine`
}

////////////////////////////////////////////////////////////////////////////

And here's the problem, when I call my first NextState it calls WanderAround which then calls DoNothing and after that it should call WanderAround again just fine, but the problem is that it simply doesn't call it. There's not a single error happening. The coroutine just doesn't wants to start. But if I call in, let's say, DoNothing StartCoroutine(WanderAround()) - it works! But not throught my weird StateTransition/Action/Execute relationship.

////////////////////////////////////////////////////////////////////////////

private IEnumerator DoNothing()
{
    Debug.Log("DoNothing:Enter");

    do
    {
        yield return new WaitForSeconds(2.5f);
    } while (CurrentState == State.Dead);

    Debug.Log("DoNothing:Exit");

    StateMachine.NextState(Input.Wandering); // Calls `StateTransition.Execute`
}

private IEnumerator WanderAround()
{
    Debug.Log("WanderAround:Enter");

    Vector2 randomPosition = new Vector2(Random.Range(-5f, 5f), Random.Range(-5f, 5f));

    movementController.RotateAndMoveTo(randomPosition, Genes[Gene.MovementSpeed], Genes[Gene.TurnSpeed]);

    while (movementController.IsMoving || movementController.IsRotating)
    {
        yield return new WaitForSeconds(Time.deltaTime);
    }

    Debug.Log("WanderAround:Exit");

    StateMachine.NextState(Input.Nothing); // Calls `StateTransition.Execute`
}

////////////////////////////////////////////////////////////////////////////

What should I do? Thanks!

PS Really sorry if this doesn't make any sense to you, I just don't know how to explain it more clearer.

Answer 1

Ok, I figured it out.

I changed my action type from IEnumerator to System.Func<IEnumerator> and... it worked!

Now my code looks like this:

////////////////////////////////////////////////////////////////////////////

public delegate void ActionCaller(IEnumerator action); // Take note of this delegate

private readonly ActionCaller caller;
private readonly System.Func<IEnumerator> action; // This is my State action

////////////////////////////////////////////////////////////////////////////

public void Execute()
{
    caller(action()); // Here I call my `action` through `caller`
}

////////////////////////////////////////////////////////////////////////////

And in StateTransition constructor I pass SomeFunc instead of SomeFunc() .

Cheers!