public void deleteItem(String dir, String file) {
		String key = null;
		if(dir!=null){
			key = dir + "/" + CHACHE_PREFIX + file;
		}else{
			key = CHACHE_PREFIX + file;
		}
		//String key = MD5.encode(CHACHE_PREFIX, uri.getBytes());
/*		if (cache.containsKey(key)) {
			cache.remove(key);
			//context.deleteFile(key);
			File dataFile= new File(app_data_dir + "/"  + key);
			if(dataFile.isFile()){
				dataFile.delete();
			}

			
		}*/

		//cache.remove(key);
		//context.deleteFile(key);
		File dataFile= new File(app_data_dir + "/"  + key);
		if(dataFile.isFile()){
			dataFile.delete();
		}

		
	
	}