Unity2D: wait for coroutine to finish to activate it again

Question

is there a way to start another coroutine once the last coroutine is finish. I have a button that activates a coroutine, the button can be pressed any time you want, when pressed you activate a coroutine. However I notice that when you press the button twice the coroutine happens twice, which is not want I want. Is there a way to make sure that once my Boomerangeffect(coroutine) is activate the coroutine can't start (if button is pressed) until the present coroutine is finished.

public GameObject BoomerangOn, BoomerangOff;
public static int buttonCount = 4;
static int timesActivated =  0;

void Start()
{
    if (PlayerPrefs.HasKey ("boomerangbutton")) {
        buttonCount = PlayerPrefs.GetInt ("boomerangbutton");
    }
}

void Update()
{
    PlayerPrefs.SetInt("boomerangbutton", buttonCount);
}

public void Activated ()
{
    if(timesActivated < buttonCount)
    {
        timesActivated++;
        StartCoroutine(BoomerangEffect());
    }
}

IEnumerator BoomerangEffect()
{

        BoomerangOn.SetActive (true);
        yield return null;
        yield return new WaitForSeconds (10.0f);
        yield return null;
        BoomerangOn.SetActive (false);
        yield return null;
        BoomerangOff.SetActive (true);
        yield return null;
        yield return new WaitForSeconds (1f);
        yield return null;
        BoomerangOff.SetActive (false);
        yield return null;
}

Answer 1

StartCoroutine returns a reference to Couroutine object. Assign it then you can simply check if that reference is null or not, if its null, start couroutine, and when the coroutine ends, set it back to null.

Coroutine boomerangEffectCoroutine;
public void Activated ()
{
    if(timesActivated < buttonCount)
    {
        timesActivated++;
        if(boomerangEffectCoroutine  == null)
             boomerangEffectCoroutine = StartCoroutine(BoomerangEffect());
    }
}
IEnumerator BoomerangEffect()
{
    // your stuffs
    boomerangEffectCoroutine = null;
}

Answer 2

Just have a bool variable keeping track whether or not the coroutine has been started. The routine can only be called if this variable is false. When the coroutine is started, set the variable to true, when it is finished set it back to false.

Could look something like this:

...
private bool coroutineRunning = false;
...
public void Activated ()
{
    if(timesActivated < buttonCount && !coroutineRunning)
    {
        timesActivated++;
        StartCoroutine(BoomerangEffect());
    }
}

IEnumerator BoomerangEffect()
{
    coroutineRunning = true;
    BoomerangOn.SetActive (true);
    ...
    BoomerangOff.SetActive (false);
    yield return null;
    coroutineRunning = false;
}