How to activate an object when another object deactivates?

Questions & Answers
1

So I have the following code:

public class Appear : MonoBehaviour
{
    public GameObject objectOne;
    public GameObject objectTwo;

    void Update()
    {
        if (objectOne.SetActive(false))
        {
            objectTwo.SetActive(true);
        }
    }
}

It doesn’t work and I don’t know why. All I want to do is activate ‘objectTwo’ when ‘objectOne’ is deactivated. So basically in the game, if an object gets de activated or destroyed, then object two will appear.

2

Make sure Appear.cs attach to other game object that not objectOne or objectTwo.
That’s all but this can be optimize for better performance later.