title: Android Service get data from database on specific time
body: <p>I have an app show my school timetable, now i trying to write a DashClock widget. I need to get current day subject from database on specific time like everyday 12am so i can publish the update to DashClock.
  I check AlarmManager, but have no idea how to set the time for run automatically on 12am and how it access to database.
  Any example or tutorial?
  Please help, thanks in advance.</p>