title: Read data from firebase, and populate in listview
body: <p>I am developing an app in which I want to read data from my firebase database, and put it in my listView.</p>
  
  <p>there are 3 different read-actions I want to have.</p>
  
  <ol>
  <li><p>When the app is first started, I want to get the 10 most recent rows read.</p></li>
  <li><p>When I reach the end of the listView, I want to get 10 more rows, starting at the oldest one that has been read so far.</p></li>
  <li><p>when I pull to the top of the listView, I want to get all the rows that has been made after the row that is now displayed as the first one. (Is that understandable...?)</p></li>
  </ol>
  
  <p><strong>Note:</strong> I have already implemented listeners for when I read the top and the end of the listview, so it's only the firebase-calls that I need.</p>
  
  <p>How should this be done?</p>