public ArrayList getSubFiles(File baseDir,String ext)
    {
        ArrayList ret = new ArrayList();
        //File base=new File(baseDir);
        File[] tmp = baseDir.listFiles();
        for (int i = 0; i < tmp.length; i++)
        {
            if (tmp[i].isFile())
            {
                if(tmp[i].getName().toLowerCase().indexOf(ext.toLowerCase())!=-1)
                  ret.add(tmp[i]);
            }
            if (tmp[i].isDirectory())
            {
                ret.addAll(getSubFiles(tmp[i],ext));
            }
        }
        return ret;
    }