Unity3D android streamingassets 复制

if (Application.platform == RuntimePlatform.Android)
 {
          WWW www = new WWW(infile);
          yield return www;
          if (www.isDone)
          {
              File.WriteAllBytes(outfile, www.bytes);
           }
          yield return 0;
}
 else
{
         if (File.Exists(outfile))
         {
              File.Delete(outfile);
         }
         File.Copy(infile, outfile, true);
}
yield return new WaitForEndOfFrame();