public static String getCacheSize() {
   if (isExternalStorageMounted()) {
     String path = SDCARD_PATH + File.separator;
     FileSize size = new FileSize(new File(path));
     return size.toString();
   }
   return "0MB";
 }
 public static String getPictureCacheSize() {
   long size = 0L;
   if (isExternalStorageMounted()) {
     String thumbnailPath = SDCARD_PATH + File.separator + PICTURE_THUMBNAIL;
     String middlePath = SDCARD_PATH + File.separator + PICTURE_BMIDDLE;
     String oriPath = SDCARD_PATH + File.separator + PICTURE_LARGE;
     size += new FileSize(new File(thumbnailPath)).getLongSize();
     size += new FileSize(new File(middlePath)).getLongSize();
     size += new FileSize(new File(oriPath)).getLongSize();
   }
   return FileSize.convertSizeToString(size);
 }