** unity ugui界面渐变效果**

      ** unity ugui界面渐变效果**

将脚本挂在canvas上，

改变对象的Alpha值改变其透明度来控制显示和隐藏（Alpha=0隐藏；Alpha=1显示）
具体代码

using UnityEngine;
using System.Collections;
using UnityEngine.UI;

public class Ui : MonoBehaviour
{
private float alpha = 0.0f;
private float alphaSpeed = 2.0f;

private CanvasGroup cg;

void Start ()
{       
    cg = this.transform.GetComponent<CanvasGroup>();        
}

void Update ()
{
    if (alpha != cg.alpha)
    {
        cg.alpha = Mathf.Lerp(cg.alpha,alpha,alphaSpeed * Time.deltaTime);
        if (Mathf.Abs(alpha-cg.alpha)<=0.01)
        {
            cg.alpha = alpha;
        }
    }
}

public void Show()
{
    alpha = 1;

    cg.blocksRaycasts = true;//可以和该UI对象交互
}

public void Hide()
{
    alpha = 0;

    cg.blocksRaycasts = false;//不可以和该UI对象交互
}