title: Update TextView in fragment's parent Activity
body: <p>I just need to modify the parent's TextView from its Child fragment. The activity is actually still showing alongside the fragment so I assume I should be able to modify it from the fragment but I have been met with an NPE so far with everything I have tried. I see some posts on updating fragments from their parent, but I need to do the opposite, and those functions have not worked thus far.</p>
  
  <p>I have put this method inside of my MainActivity(the parent) to allow updating of the TextView from the fragment.</p>
  
  <pre><code> public void updateGoldTextView(int goldAmount) {
      goldTV.setText(String.valueOf(goldAmount));
  }
  </code></pre>
  
  <p>In my fragment I am calling the method as so:</p>
  
  <pre><code>MainActivity mainActivity = new MainActivity();
  mainActivity.updateGoldTextView(50);
  </code></pre>
  
  <p>What do I need to do in my fragment to allow me to reference this properly?</p>