title: (android.support.v4.widget.DrawerLayout$DrawerListener)' on a null object reference
body: <p>Can you help me about this error on my logcat? 
  <a href="http://pastebin.com/uSXruD54" rel="nofollow noreferrer">http://pastebin.com/uSXruD54</a> </p>
  
  <p>Where: </p>
  
  <pre><code>Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.widget.DrawerLayout.setDrawerListener(android.support.v4.widget.DrawerLayout$DrawerListener)' on a null object reference
  </code></pre>
  
  <p>on my Home class at line 79 which is:       </p>
  
  <pre><code>drawer.setDrawerListener(toggle);
  </code></pre>
  
  <p><a href="http://pastebin.com/cixZ7d9d" rel="nofollow noreferrer">http://pastebin.com/cixZ7d9d</a> (MainActivity class, line 48)</p>
  
  <p>I don't have any idea how setDrawerListener works sorry, I found the same problem here on stackoverflow: <a href="https://stackoverflow.com/questions/31500963/how-to-rectify-nullpointerexception-in-v4-drawerlayout">How to rectify NullPointerException in v4.DrawerLayout?</a></p>
  
  <p>The answer says that it has to make sure that I'm using the same id for nav drawer and in layout file but I didn't made any changes on nav drawer because it's the activity itself that I chose in Android Studio, I just implemented tabs on it.</p>