variable listener

Unity Engine
1

Is there any way to trigger an event if a variable from another scripts changes without calling it in update(). I would love to avoid calling everything in update.
In my case I have a time/date variable and I was wondering if there is a way for other scripts to see if the time was changed without using Update().

Thank you,
Hapciupalit

2

You can use a get set and run a function each time the value is set or have it fire a custom event.

3

Ok… and can put other scripts to listen to that event?

4

Ok course. This is one way you could do it, I wouldn’t say its the best way as I’m no expert :stuck_out_tongue:

The script containing the variable you want to monitor;

using UnityEngine;

public class EventSender : MonoBehaviour
{
    private float _myFloat = 0f;

    public event OnVariableChangeDelegate OnVariableChange;
    public delegate void OnVariableChangeDelegate(float newVal);

    public float MyFloat
    {
        get
        {
            return _myFloat;
        }
        set
        {
            if (_myFloat == value) return;
            _myFloat = value;
            if (OnVariableChange != null)
                OnVariableChange(_myFloat);
        }
    }
}

The script containing the code you wish to listen for changes in your variable;

using UnityEngine;

public class EventListener : MonoBehaviour
{
    private EventSender _eventSender;

    void Start()
    {

        _eventSender = GameObject.FindObjectOfType<EventSender>();

        _eventSender.OnVariableChange += VariableChangeHandler;
    }

    private void VariableChangeHandler(float newVal)
    {
        Debug.Log("Event Fired. MyFloat = " + newVal);
    }

    private void Update()
    {
        //For Testing
        if (Input.GetKeyDown(KeyCode.DownArrow))
        {
            _eventSender.MyFloat -= 0.5f;
        }
        else if (Input.GetKeyDown(KeyCode.UpArrow))
        {
            _eventSender.MyFloat += 0.5f;
        }
    }
}
4 Likes
5

Thank you very much. This is just perfect. For me as long as it works … I don’t care if it’s the best solution.

1 Like
6

This looks pretty useful but I cant get worked that. Even when I use exact same code I do receive nothing, even no feedback and no error.

its an old post but if you guys are still alive, can you please help me.

thanks

1 Like