unity 代码更换ugui中image的关联素材

using UnityEngine;  
using System.Collections;  
using UnityEngine.UI;  
    
public class Test : MonoBehaviour {  
    
    [SerializeField]  
    Image myImage;  
    
    // Use this for initialization  
    void Start () {  
        StartCoroutine(GetImage());  
    }  
    
    IEnumerator GetImage()  
    {  
        string url = "http://www.5dbb.com/images/logo.gif";  
        WWW www = new WWW(url);  
        yield return www;  
        if (string.IsNullOrEmpty(www.error))  
        {  
            Texture2D tex = www.texture;  
            Sprite temp = Sprite.Create(tex, new Rect(0, 0, tex.width, tex.height), new Vector2(0, 0));  
            myImage.sprite = temp;  
        }  
    }  
}