title: Timer in Android - how to keep counting even when phone or app is off
body: <p>I am trying to implement a timer that just counts the time passed since pressed start. I need to keep this counter even if the app/phone is off. How do I achieve this? Store the current time somewhere when the app is turned off, and then retrieve this data when the app is on again? And if this is a good way to do it, how do I implement this solution? I hope someone has some input. </p>
  
  <p>I have implemented my timer/counter using Handler (I saw this solution in an answer here on StackOverflow)</p>