使用NGUI来制作技能的CD冷却效果

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CDScripts : MonoBehaviour {

    public int cd_time = ;         //技能的冷却速度
    public bool cd_isCan = false;       //是否可以释放技能的标志位

    private  UISprite cd_sprite;

    private void Awake()
    {
        cd_sprite = GameObject.Find("Sprite").GetComponent<UISprite>();
    }

    // Update is called once per frame
    void Update ()
    {
        if(Input.GetKeyDown(KeyCode.A)&&cd_isCan==false)
        {
            cd_sprite.fillAmount = 1.0f;
            cd_isCan = true;
        }
        if(cd_isCan==true)
        {
            cd_sprite.fillAmount -= (1f / cd_time) * Time.deltaTime;     //对技能的冷却效果进行减少
            if (cd_sprite.fillAmount <= 0.05)
            {
                cd_sprite.fillAmount = 0f;

                cd_isCan = false;       //技能的冷却时间满足了
            }
        }

    }
}