title: How to get current fragment from MainActivity
body: <p>I've done some research but I really couldn't find the answer.</p>
  
  <p>I have single activity with side menu, and holder. I have many (<strong><em>non support</em></strong>) fragments, and all of them are using same holder (one at a time). </p>
  
  <p>When user uses menu (it's in main activity), and goes another page, I want to add name of the current fragment to backstack (using <code>.addToBackStack(Fragment1.class.getName())</code>), but I couldn't find how to get current fragment. </p>
  
  <p>I don't want to implement interface etc to keep track of current fragment. There is a super simple way using fragmentManger isn't there?</p>