code: public String getPlayingTimeString()
  	{
  		long time = getPlayingTime();
  		long mins = time / 60;
  		long secs = time % 60;
  
  		StringBuilder str = new StringBuilder();
  		if (mins<10) str.append('0');
  		str.append(mins).append(':');
  		if (secs<10) str.append('0');
  		str.append(secs);
  		return str.toString();
  	}
docs: Return a formatted version of the getPlayingTime method.  The string
  will be formated "m:ss" where 'm' is minutes and 'ss' is seconds.
  
  @return a formatted version of the getPlayingTime method