void Update () 
{
        if (canvasGroup == null)
        {
            return;
        }
 
        if (UI_Alpha != canvasGroup.alpha)
        {
            canvasGroup.alpha = Mathf.Lerp(canvasGroup.alpha, UI_Alpha, alphaSpeed * Time.deltaTime);
            if (Mathf.Abs(UI_Alpha - canvasGroup.alpha) <= 0.01f)
            {
                canvasGroup.alpha = UI_Alpha;
            }
        }
}


    public void UI_FadeIn_Event()
    {
        UI_Alpha = 1;
        canvasGroup.blocksRaycasts = true;      //可以和该对象交互
    }



    public void UI_FadeOut_Event()
    {
        UI_Alpha = 0;
        canvasGroup.blocksRaycasts = false;     //不可以和该对象交互
    }