U3D assetbundle加载

 using UnityEngine;
 using System.Collections;
 public class testLoadFromAB : MonoBehaviour {

     IEnumerator DownloadAndCache()
     {
         while (!Caching.ready)
             yield return null;

         //注意，从本地加载时，必须使用前缀 file:///或file://，从网络加载则使用 http://，这两种协议可以在iphone和WINDOWS, 安卓上通用
         //UNITY MANUAL:
         //http://, https:// and file:// protocols are supported on iPhone.
         //ftp:// protocol support is limited to anonymous downloads only. Other protocols are not supported.
         WWW www = WWW.LoadFromCacheOrDownload ("file:///Z:/unity/learn-test/Assets/AssetBundles/cubes.unity3d", );
         yield return www;
         if(!string.IsNullOrEmpty (www.error)){//有些平台不支持string为null，这种写法可以避免意外
             Debug.LogError (www.error);
             yield break;
         }

         AssetBundle bundle = www.assetBundle;

         //注意必须使用Instantiate实例化出来才能将两个CUBE显示到场景中
         GameObject cube1 = Instantiate (bundle.LoadAsset ("DecalCube2")) as GameObject;
         GameObject cube2 = Instantiate (bundle.LoadAsset ("DecalCube3")) as GameObject;

     }
     // Use this for initialization
     void Start () {
         StartCoroutine ("DownloadAndCache");
     }

     // Update is called once per frame
     void Update () {

     }
 }