title: How to set timer to call a function every n minutes?
body: <p>I want to set up a timer in an Android application that will call a function after every 15/30/45 and n minutes when user login. But also it will stop timer when user log off. and timer begin from start if user login again. I want that option(15/30/45/n miutes) to be saved in database so that I can update list after sync.</p>
  
  <p>Is Timer a good approach or I need to use alarm services? Or is there any system services required?</p>
  
  <p>Is it possible to change previous doc/file in local phone database storage to new doc that is receiving through web server? is there any system services required to do so?</p>