InternalStorageObserver

    private class PathFileObserver extends FileObserver{
        static final String TAG="FILEOBSERVER";
        /**
         * should be end with File.separator
         */
    	String rootPath;
    	static final int mask = (FileObserver.CREATE | 
    			FileObserver.DELETE | 
    			FileObserver.DELETE_SELF |
    			FileObserver.MODIFY |
    			FileObserver.MOVED_FROM |
    			FileObserver.MOVED_TO |
    			FileObserver.MOVE_SELF); 
    	
    	public PathFileObserver(String root){
    		super(root, mask);

    		if (! root.endsWith(File.separator)){
    			root += File.separator;
    		}
    		rootPath = root;
    	}

    	public void onEvent(int event, String path) {
    		
    		switch(event){
    		case FileObserver.CREATE:
    			Log.d(TAG, "CREATE:" + rootPath + path);
    			break;
    		case FileObserver.DELETE:
    			Log.d(TAG, "DELETE:" + rootPath + path);
    			break;
    		case FileObserver.DELETE_SELF:
    			Log.d(TAG, "DELETE_SELF:" + rootPath + path);
    			break;
    		case FileObserver.MODIFY:
    			Log.d(TAG, "MODIFY:" + rootPath + path);
    			break;
    		case FileObserver.MOVED_FROM:
    			Log.d(TAG, "MOVED_FROM:" + rootPath + path);
    			break;
    		case FileObserver.MOVED_TO:
    			Log.d(TAG, "MOVED_TO:" + path);
    			break;
    		case FileObserver.MOVE_SELF:
    			Log.d(TAG, "MOVE_SELF:" + path);
    			break;
    		default:
    			// just ignore
    			break;
    		}
    	}

    	public void close(){
    		super.finalize();
    	}
    }