Question

I hope someone can help. Im trying to set up a timer that times from the start of a game and displays this time. The problem is that the following section of code gives me the wrong time. Its in the wrong format, and is out by an hour.

private long startTime;
private SimpleDateFormat timeFormat = new SimpleDateFormat("HH:mm:ss.SS");

//Constructor:
startTime = System.currentTimeMillis();

public String getTime() {
long gameTime = System.currentTimeMillis() - startTime;
final Date date = new Date(gameTime);
return timeFormat.format(date);
}

It consistently gives me the output of 01:00:03:203. The seconds are correct, but the 1 hour shouldn’t be there, and for format is 3 decimal places instead of the two I thought I specified.

Thank you very much!

Answer 1

Your date is epoch + gameTime. I think you’re experiencing a daylight saving shift since the current DST in your location today doesn’t match the DST at epoch.

Use a Calendar instead of a Date. Start with today and explicitly wipe out the hour, minute, etc. parts:

Calendar cal = Calendar.getInstance();
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 3600000 + 60000 + 1000 + 1);

SimpleDateFormat timeFormat = new SimpleDateFormat("HH:mm:ss.SS");

System.out.println(timeFormat.format(cal.getTime()));

The output for the above is: 01:01:01.01

http://ideone.com/DyQcl

Substitute the numbers I have above with gameTime and you’re done.

Of course, this may not work once your millisecond ticks exceed the day boundary.