An option to display a floating bar on the desktop.
Inspiration can be taken from these screenshots http://www.priacta.com/trog/Quick_Start … rc=support.
This assistance “always near hands” helps to focus on things to do and would be adapted to support a new feature as well : time tracking.
Regarding time tracking, there are 2 excellent time tracking android applications :
https://play.google.com/store/apps/deta … mRpbmciXQ…
https://play.google.com/store/apps/deta … .planmyday
I suggest you choose the one you prefer to catch data generated by the app in order Em client can manage them, ie sync.
Time Recording may be easier to choose as it can sync with Google Calendar so it would just has to catch data from Google Calendar.