Milliseconds computation

Question

Hi there and thanks for visiting. I'm writing an application that draws a circle and then draws a random number of circles and allows the user to guess how many circles are within the larger circle. They input a number into a textarea and click a button and they are given a fresh circle with a new random number of dots within that circle. This all works great. The person I'm writing the program for requested to know roughly how much time the person spent looking at each slide of circles. I figured this would be know problem. What I thought would work is when the application first runs I take a time stamp in milliseconds using the following code:
long timeStamp = System.getTimeInMillis();Then when the user makes their guess and pressed the button, I take another time stamp using the same code above and subtract that time with the one previously taken. I'm assuming this will give me the number of milliseconds spent. However, when I do a System.out.println(""+timeSpent), I ALWAYS get zero. I looked online for like 3 hours as to how to do this an all I get are negative numbers etc. I'm wanting to save this time difference to a file too. I can do all this, but this millisecond math computation is confusing and is not working for me. Any help would be GREATLY appreciated. Thanks!

Answer 1

Darryl.Burke wrote:
scoobasteve1982 wrote:
I take a time stamp in milliseconds using the following code:
long timeStamp = System.getTimeInMillis();
The only method with this signature in the API "G" Index is:
getTimeInMillis(): Method in class java.util.Calendar
Returns this Calendar's time value in milliseconds.
You wouldn't by any chance have a Calendar reference variable named System, now, would you? coz that's one way that might compile -- and return zero -- another is if you have a custom class named System.
dbI was wondering about that too, just assumed it was a typo and he wrote the Calendar version instead of the System version and that his actual code did it correctly, since it wouldn't compile otherwise. But you're right, if he made a Calendar var named System....