How to get the first component that implements a specific interface ?

Questions & Answers
1

Is there a beter (more style / more performant) way of getting the first (and hopefully only) component that implements a specific interface ?

public interface IFoo
{
    void iFooMethod();
}

public class Foo
{
    void OnCollisionEnter(Collision collision)
    {
        IFoo fooObject = null;
        MonoBehaviour[] components = collision.transform.root.GetComponents();
        foreach(MonoBehaviour component in components)
            if(component is IFoo)
            {
                fooObject = component as IFoo;
                break;
            }
        if(fooObject != null) fooObject.iFooMethod();
    }
}

It just feels like I'm missing something ala GetComponentWithInterface.Blockquote

3

You can’t use the generic method, but this form seems to work fine:

IFoo foo = (IFoo)gameObject.GetComponent(typeof(IFoo));

Probably too late for the OP, but perhaps this helps someone else :slight_smile: .

4

As of Unity 5, you can use the generic form of GetComponent on interfaces:

IFoo foo = gameObject.GetComponent<IFoo>();
IFoo[] foos = gameObject.GetComponents<IFoo>();

Alternatively, .GetComponent(typeof(IFoo)) works for old versions of Unity and .GetComponents(typeof(IFoo)) (with an ‘s’) also works from Unity 4.6 onwards.

2

I beleive that whole code block could be condensed down to the following:

void OnCollisionEnter(Collision collision)
{
    collision.transform.root.GetComponent<IFoo>().iFooMethod();
}
5

y’all are making it way too complicated.
this works perfectly:

public class Hit : MonoBehaviour
    {
        void OnTriggerEnter(Collider other)
        {
            if (other.GetComponent<IDamageable>() != null)
            {
                print("HIT INTERFACE");
            }
        }
    }