我看到官方文档中说明：

Note that bundles are not fully compatible between platforms. A bundle built for any of the standalone platforms (including webplayer) can be loaded on any of those platforms but not on iOS or Android. Furthermore, a bundle built for iOS is not compatible with Android and vice versa.

但是我们看到，用以下步骤进行在Android机子上使用AssetBundle

重点有2点：

1. Use the option "BuildTarget.Android".
2. Describe the path with triple slash "file:///"

以下是步骤：

1. Delete directories "Per Texture Materials", "assetbundles", and so on.  把已经导出过的包删掉
2. Use the option "BuildTarget.Android" to all "BuildPipeline.BuildAssetBundle".   要把BuildTarget为Android平台！！！
3. Run these on Editor. Character Generator/Generate Materials Character Generator/Create Assetbundles Character Generator/Update Character Element Database  
4. Copy Assetbundles database to Android device which like "/mnt/sdcard/assetbundles/"  把这些包放到Android的指定目录下
5. Modify AssetbundleBaseURL. (the point was "file:///") 修改获取AssetbundleBaseURL基础路径的地址

public static string AssetbundleBaseURL{    get    {        if (Application.platform == RuntimePlatform.WindowsWebPlayer || Application.platform == RuntimePlatform.OSXWebPlayer)        {            return Application.dataPath + "/assetbundles/";        }        else if (Application.platform == RuntimePlatform.Android)        {            return "file:///mnt/sdcard/assetbundles/";        }        else        {            return "file://" + Application.dataPath + "/../assetbundles/";        }    }}