Log buttons clicked and other user activity?

Is there a way to log all the buttons clicked on any form in my application from a central place (in the same application)?

I have a very big application so adding code to each button click will be a very big task.
If I can have an API function to log all button clicks on all forms, logging button name, form, etc it will help a lot.

Does anyone have any ideas?
Maybe API calls are not even needed?

:confused: