title: reload a fragment android if exist else create it
body: <p>I'm using <code>android.support.v4.app.Fragment</code> and android 2.3 version, so i wont if i click a button to create an instance of my fragment it verify his existance before, and in the case that it exist i should reload it and not create another instance.
  This is the code that i use:</p>
  
  <pre><code>private void addNewFragment(Fragment fragment) {
      FragmentManager manager = getSupportFragmentManager();
      FragmentTransaction transaction = manager.beginTransaction();
      transaction.replace(R.id.myFragment, fragment, LEADERBOARD_FRAG_TAG);
      transaction.addToBackStack(null);
      transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
      transaction.commit();
      }
  </code></pre>
  
  <p>thanks a lot.</p>