Is there a way to detect what application receives focus?

Is there a way to detect what application receives focus and so is currently using from user ?

For instance, I can know when a user is using Firefox, notepad, vlc, ecc.

The intent is to tie it into a timetracking tool so that I can keep track of how much time the user spend being开发者_Go百科 unproductive.

http://msdn.microsoft.com/en-us/library/ms633505(v=vs.85).aspx

this is what you're looking for.

BTW, I'm making the same thing.

There are several existing solutions for this though, but they just don't meet some of my specific demands.

Check this out, maybe you don't need to make it, if you find what you need
http://en.wikipedia.org/wiki/Comparison_of_time_tracking_software