NGUI实现技能CD效果

public class Skill : MonoBehaviour {
    //冷却时间
    public float coldTime = 1f;
    //是否正在冷却
    private bool isColding = false;
    private UISprite shade_Sprite;

    void Awake()
    {
        //var Skill001_Shade = GameObject.Find("UI Root/Skill_Window/Skill_Border/Skill001/Shade_Sprite");
        //shade_Sprite = Skill001_Shade.GetComponent<UISprite>();
        shade_Sprite = gameObject.transform.Find("Shade_Sprite").GetComponent<UISprite>();
        UIEventListener.Get(this.gameObject).onClick += StartSkill;
    }
    void Update()
    {
        if (Input.GetKey(KeyCode.N) && !isColding)
        {
            //TODO 触发技能，技能特效等
            shade_Sprite.fillAmount = 1;
            isColding = true;
        }

        if (isColding)
        {
            shade_Sprite.fillAmount -= (1f/coldTime)*Time.deltaTime;
            if (shade_Sprite.fillAmount <= 0.001)
            {
                shade_Sprite.fillAmount = 0;
                isColding = false;
            }
        }

    }

    void StartSkill(GameObject go)
    {
        if ( !isColding)
        {
            //TODO 触发技能，技能特效等
            shade_Sprite.fillAmount = 1;
            isColding = true;
        }
    }   

}