private SDCardStorageManager() {
		//context = ZApplication.getInstance();
		//cache = new HashMap<String, StorageValue>();
		gson = new Gson();

		Log.e(TAG, "Environment.getExternalStorageDirectory() : " + Environment.getExternalStorageDirectory());
		File appDataPath = new File(Environment.getExternalStorageDirectory(), storage_dir_in_sdcard);
		app_data_dir = appDataPath.getAbsolutePath();
		Log.e(TAG, "app_data_dir : " + app_data_dir);
		if(!appDataPath.exists()) {
			appDataPath.mkdirs();
		}
		load(app_data_dir);
	

	}