title: getChildFragmentManager() method is undefined
body: <p>I have the same issue has this post: <a href="https://stackoverflow.com/questions/15805574/android-support-v4-app-fragment-undefined-method-getchildfragmentmanager">android.support.v4.app.Fragment: undefined method getChildFragmentManager()</a>. I need to use <code>getChildFragmentManager()</code> because I'm using nested fragments.</p>
  
  <p>My problem is: the solution in the other post does not work for me:</p>
  
  <ul>
  <li>My SDK is updated.</li>
  <li>I got my android-support-v4 from the SDK folder.</li>
  <li>I added android-support-v4 both the my project and ABS.</li>
  </ul>
  
  <p>Here is my libs:</p>
  
  <p><img src="https://i.stack.imgur.com/V5qNl.png" alt="enter image description here"></p>
  
  <p>How can I correctly use this method?</p>