java - How to measure elapsed time

I have a 10 and 20 question game. I need to count how much time is passed when a user finishes the game.

Timer T=new Timer();
T.scheduleAtFixedRate(new TimerTask() {         
    @Override
    public void run() {
        runOnUiThread(new Runnable()
        {                
            public void run()

            {
                countdown.setText(""+count);
                count++;                
            }
        });
    }
}, 1000, 1000);

I use this to stop the counter:

T.cancel();

Now I need two things:

• A way how to count the elapsed time and store it in a variable


• I need the final value to be a double, for example final score is: 15.49 seconds.

Answer

When the game starts:

long tStart = System.currentTimeMillis();

When the game ends:

long tEnd = System.currentTimeMillis();
long tDelta = tEnd - tStart;

double elapsedSeconds = tDelta / 1000.0;