代码动态更换MeshRenderer的材质Materials

public class metrailstest : MonoBehaviour
{
    Material[] m;
    Material i;
    public Material[] n;
    int index = 0;
    // Use this for initialization
    void Start()
    {
        i = this.GetComponent<MeshRenderer>().material;
        m = this.GetComponent<MeshRenderer>().materials;
    }

    // Update is called once per frame
    void Update()
    {
        if (Input.GetKeyDown(KeyCode.A))
        {
            index++;
            if (index % 2 == 0)
                this.GetComponent<MeshRenderer>().materials = n;
            else
                this.GetComponent<MeshRenderer>().materials = m;
        }
    }
}