协程完成后如何继续功能？

Question

void Generate()
{
    StartCoroutine(FallDelayCoroutine());
    print("time3- " + Time.time);
}

IEnumerator FallDelayCoroutine()
{     
    print("time1- "+ Time.time);
    yield return new WaitForSeconds(3f);
    print("time2- " + Time.time);
}

Output:

time1- 0
time3- 0
time2- 3.0146

Output that i want is:

time1- 0
time2- 3
time3- 3

Answer 1

The documentation at https://docs.unity3d.com/ScriptReference/MonoBehaviour.StartCoroutine.html seems to have an example that is almost identical to what you are trying to do:

IEnumerator Start()
{
    // - After 0 seconds, prints "Starting 0.0"
    // - After 2 seconds, prints "WaitAndPrint 2.0"
    // - After 2 seconds, prints "Done 2.0"
    print("Starting " + Time.time);

    // Start function WaitAndPrint as a coroutine. And wait until it is completed.
    // the same as yield WaitAndPrint(2.0);
    yield return StartCoroutine(WaitAndPrint(2.0F));
    print("Done " + Time.time);
}

// suspend execution for waitTime seconds
IEnumerator WaitAndPrint(float waitTime)
{
    yield return new WaitForSeconds(waitTime);
    print("WaitAndPrint " + Time.time);
}

The key point seems to be that their Start routine returns IEnumerator and then uses yield return StartCoroutine(WaitAndPrint(2.0F)); to force it to wait on that method before continuing.

So the equivalent for you would be:

IEnumerator Generate()
{
    yield return StartCoroutine(FallDelayCoroutine());
    print("time3- " + Time.time);
}

Answer 2

As alternative to the other answer using two Coroutines you could also add a callback like eg

IEnumerator FallDelayCoroutine(Action whenDone)
{     
    print("time1- "+ Time.time);
    yield return new WaitForSeconds(3f);
    print("time2- " + Time.time);

    whenDone?.Invoke();
}

and call it either using eg a lambda expression

void Generate()
{
    StartCoroutine(FallDelayCoroutine(() => {
        print("time3- " + Time.time);
    }));  
}

or with a method

void Generate()
{
    StartCoroutine(FallDelayCoroutine(OnFallDelayDone));  
}

private void OnFallDelayDone()
{
    print("time3- " + Time.time);
}