title: Android Toolbar Issue
body: <p>Recently, my onCreate() method has been having a hard time connecting a Toolbar to a toolbar in my xml file.</p>
  
  <p>Code:</p>
  
  <pre><code> super.onCreate(savedInstanceState);
   setContentView(R.layout.content_two_player_game);
   Toolbar toolbar = (Toolbar) findViewById(R.id.two_player_toolbar);
   setSupportActionBar(toolbar);
  </code></pre>
  
  <p>The app compiles and runs in the main screen and the single player screen, but when I try and start the two player screen, it crashes. The ID is correct and yet the toolbar is still Null when I try setSupportActionBar(toolbar).</p>
  
  <p>My error:</p>
  
  <pre><code>    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.phoenixdev.yahtzee/com.***.***.TwoPlayerActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.support.v7.widget.Toolbar.getTitle()' on a null object reference
  </code></pre>
  
  <p>The activity_two_player_game.xml file:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:fitsSystemWindows="true"
      tools:context="com.phoenixdev.yahtzee.TwoPlayerActivity"&gt;
  
      &lt;android.support.design.widget.AppBarLayout
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:theme="@style/AppTheme.AppBarOverlay"&gt;
  
          &lt;android.support.v7.widget.Toolbar
              android:id="@+id/two_player_toolbar"
              android:layout_width="match_parent"
              android:layout_height="?attr/actionBarSize"
              android:background="?attr/colorPrimary"
              app:popupTheme="@style/AppTheme.PopupOverlay" /&gt;
  
      &lt;/android.support.design.widget.AppBarLayout&gt;
  
      &lt;include layout="@layout/content_two_player_game" /&gt;
  
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>