title: Refresh data in ViewPager when returning
body: <p>Activity A:
  <a href="https://i.stack.imgur.com/yJn3W.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yJn3W.png" alt="enter image description here"></a>
  In this activity there is 1 ViewPager containing 2 Fragments which contain a List of Products. 1 for recent products and 1 for popular products. When i click on a product (regardless which fragment is active) i will go to the detailview of that product (See picture of Activity B).</p>
  
  <p>Activity B:
  <a href="https://i.stack.imgur.com/qUNRR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qUNRR.png" alt="enter image description here"></a>
  In this activity there are the possiblities to like, reply to and share a prodoct by clicking the corresponding floathingActionButton. When one of these actions is performed, the data in this activity is updated.</p>
  
  <p>The data will be kept in an singleton which is accessable in both activities. When an action in performed in Activity B, the data will be updated. However when i go back to Activity A, the lists in both activities are not refreshed. 
  I have tried overwrite the pager in the onRestart in Activity A, but the data did not refresh.</p>
  
  <p>How can I make this happen?</p>