title: How to refresh visible data when it becomes outdated on Android?
body: <p>In an activity I'm showing some data. I calculate the data in a <code>ViewModel</code> and store it in a <code>LiveData</code>.</p>
  <p>Now the problem is that the data refers to the current day, so at midnight it becomes outdated and needs to be recalculated if it is still currently displayed.</p>
  <p>Should I do this in the <code>Activity</code> or in the <code>ViewModel</code> and what kind of timer should I use for this?</p>