Coroutine inside for loop not working

Questions & Answers
1

Hi. I am trying to implement a for loop with a small delay between each iteration using coroutines, but for some reason can’t get it to work… The for loop inside the coroutine only happens once regardless of what I type in. What is the problem here?

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System;

public class Experience : MonoBehaviour
{
    float speed = 3f;
    public bool lockedOn = false;
    bool hasReachedTarget = false;
    public int expAmount = 1;

    Action<GameObject> _killAction;

    public List<Experience> experiencesInRange = new();

    public GameObject target;

    private void OnTriggerEnter2D(Collider2D collision)
    {
        if(collision.CompareTag("Player"))
        {
            lockedOn = true;
            target = collision.gameObject;
        } else if (collision.CompareTag("Experience") && !lockedOn)
        {
            var exp = collision.GetComponent<Experience>();

            if (exp.expAmount > 5) return;

            if(expAmount <= 5)
            {
                experiencesInRange.Add(exp);
                CheckExperience();
            }
            else
            {
                expAmount += exp.expAmount;
                exp.target = gameObject;
                exp.lockedOn = true;
            }
        }
    }

    private void OnTriggerExit2D(Collider2D collision)
    {
        if (collision.CompareTag("Experience"))
        {
            experiencesInRange.Remove(collision.GetComponent<Experience>());
        }
    }

    private void OnDisable()
    {
        lockedOn = false;
        speed = 3;
    }

    private void Update()
    {
        if (lockedOn)
        {
            if (target == null) target = GlobalData.player;
            Vector2 direction = (target.transform.position - transform.position).normalized;
            transform.position += (Vector3)direction * Time.deltaTime * 3 * speed;
            speed += Time.deltaTime * 2;
            if (Vector2.Distance(target.transform.position, transform.position) <= 0.3f)
            {
                if (target.CompareTag("Player") && !hasReachedTarget)
                {
                    StartCoroutine(GetExp(expAmount));
                    _killAction(gameObject);
                } else if (target.CompareTag("Experience"))
                {
                    Destroy(gameObject);
                }
            }
        }
    }

    public void Init(Action<GameObject> killAction)
    {
        _killAction = killAction;
    }

    void CheckExperience()
    {
        int totalExp = expAmount;
        foreach(Experience exp in experiencesInRange)
        {
            totalExp += exp.expAmount;
        }

        if(totalExp > 5)
        {
            GetComponent<SpriteRenderer>().color = Color.red;
            expAmount = totalExp;
            for(int i = 0; i < experiencesInRange.Count; i++)
            {
                experiencesInRange*.target = gameObject;*

experiencesInRange*.lockedOn = true;*
}
experiencesInRange.Clear();
}
}

IEnumerator GetExp(int expAmount)
{
hasReachedTarget = true;
for (int i = 0; i<expAmount; i++)
{
Debug.Log(“One experience”);
target.GetComponent().Exp++;
yield return new WaitForSeconds(.001f);
}
Destroy(gameObject);
}
}

4

Are you sure, you don’t have enabled “collapse” in the console window?

Note that such small WaitForSecond calls are completely pointless. A yield will take at least one frame. So it can never be faster than the framerate. You certainly don’t have 1000 fps so your loop would only cycle once every frame.

Also are you sure that you don’t destroy the object immediately somewhere else? Any running coroutine on objects that are destroyed would simply vanish.

2

Maybe expAmount = 1 that’s why for loop is only executing one time. Have you check the value of expAmount by doing Debug.Log(expAmount);

3

Yes I have tried that and it debugs the right amount of exp, and even if i hardcode the forloop to loop 10 times it still only happens once…

IEnumerator GetExp(int expAmount)
     {
         //this code also only happens once
         hasReachedTarget = true;
         for (int i = 0; i<10; i++)
         {
             Debug.Log("One experience");
             target.GetComponent<PlayerStats>().Exp++;
             yield return new WaitForSeconds(.001f);
         }
         Destroy(gameObject);
     }