How to delay a method in Unity and C#?

Question

My name is Laurenz and my question is how to delay the color changing of my sprites in Unity with c#.

Right now I have a random generator which choses a color based on a number, but this happens every frame. So now the real challenge is how to delay it so that it changes less often.

public class colorchange : MonoBehaviour
{
    public int color;
    public bool stop = true;
    void Start()
    {

    }

    void Update()
    {

        Debug.Log("Hello");
        color = Random.Range(1, 5);
        if (color == 2)
        {
            gameObject.GetComponent<SpriteRenderer>().color = Color.blue;
        }
        if (color == 3)
        { 
            gameObject.GetComponent<SpriteRenderer>().color = Color.red;
        }
        if (color == 4)
        {
            gameObject.GetComponent<SpriteRenderer>().color = Color.yellow;
        }
    }
}

Answer 1

You can put your code in a loop in a Coroutine that iterates once every number of seconds:

public class colorchange : MonoBehaviour
{
    public int color;        
    public float delaySeconds = 1f;
    IEnumerator changeColorCoroutine;

    SpriteRenderer mySprite;

    public bool doChangeColor;

    void Start()
    {
        // cache result of expensive GetComponent call
        mySprite = GetComponent<SpriteRenderer>();

        // initialize flag
        doChangeColor = true;

        // create coroutine
        changeColorCoroutine = ChangeColor();

        // start coroutine
        StartCoroutine(changeColorCoroutine);
    }

    void OnMouseDown()
    {
        // toggle doChangeColor
        doChangeColor = !doChangeColor;
    }

    IEnumerator ChangeColor()
    {
        WaitUntil waitForFlag = new WaitUntil( () => doChangeColor);

        while (true)
        {
            yield return waitForFlag;

            Debug.Log("Hello");
            color = Random.Range(1, 5);

            // switch for neater code
            switch (color)
            {
            case 2:
                mySprite.color = Color.blue;
                break;

            case 3:
                mySprite.color = Color.red;
                break;

            case 4:
                mySprite.color = Color.yellow;
                break;
            }

            yield return new WaitForSeconds(delaySeconds);
        }
    }
}