Loop function on button press? Unity3d C#

Question

So, I have an object. When I press Spin Button, I want it to spin. When I press Stop button, I want it to stop.

It spins fine when its in void Update, but when its i

Answer 1

The for loop isn't working as expected because you are not waiting for a frame. Basically, it will do all the spinning in one frame and you won't see the changes until the final spin. Waiting for a frame can the done with yield return null; and that requires a coroutine function.

This is better done with a coroutine. You can use boolean variable with a coroutine or you can just use StartCoroutine and StopCoroutine. Start coorutine that spins the Object when the start Button is clicked and then stop the coroutine when the stop Button is clicked.

public float speed = 500f;
public Button starter;
public Button stopper;
bool isSpinning = false;

IEnumerator spinnerCoroutine;

void Start()
{
    //The spin function
    spinnerCoroutine = spinCOR();

    Button btn = starter.GetComponent<Button>();
    Button butn = stopper.GetComponent<Button>();

    butn.onClick.AddListener(FidgetSpinnerStop);
    btn.onClick.AddListener(FidgetSpinnerStart);
}

IEnumerator spinCOR()
{
    //Spin forever untill FidgetSpinnerStop is called 
    while (true)
    {
        transform.Rotate(Vector3.up, speed * Time.deltaTime);
        //Wait for the next frame
        yield return null;
    }
}

void FidgetSpinnerStart()
{
    //Spin only if it is not spinning
    if (!isSpinning)
    {
        isSpinning = true;
        StartCoroutine(spinnerCoroutine);
    }
}

void FidgetSpinnerStop()
{
    //Stop Spinning only if it is already spinning
    if (isSpinning)
    {
        StopCoroutine(spinnerCoroutine);
        isSpinning = false;
    }
}

Answer 2

Following is a simple class that start and stops spinning an object using two buttons, I hope it makes a starting point of what you are trying to achieve.

public class TestSpin : MonoBehaviour
{
    public float speed = 500f;
    public Button starter;
    public Button stopper;

    bool IsRotating = false;

    void Start()
    {

        Button btn = starter.GetComponent<Button>();
        Button butn = stopper.GetComponent<Button>();

        butn.onClick.AddListener(FidgetSpinnerStop);
        btn.onClick.AddListener(FidgetSpinnerStart);
    }

    void FidgetSpinnerStart()
    {
        IsRotating = true;
    }

    void FidgetSpinnerStop()
    {
        IsRotating = false;
    }

    void Update()
    {
        if (IsRotating)
            transform.Rotate(0, speed, 0);
    }
}