title: NullPointerException while setting toolbar
body: <p>I've got the following XML Layout :</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      android:orientation="vertical"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:id="@+id/mycloud"&gt;
  
      &lt;include
          android:id="@+id/app_bar"
          layout="@layout/tool_bar" /&gt;
  
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>With the include tool_bar being :</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:background="@color/primaryColour"
      android:paddingTop="0dp"
      app:title="Noteu"
      app:theme="@style/myCustomToolBarTheme"
      app:popupTheme="@style/ThemeOverlay.AppCompat.Dark"
      &gt;
  
  &lt;/android.support.v7.widget.Toolbar&gt;
  </code></pre>
  
  <p>However when I try to set the toolbar with the following class :</p>
  
  <pre><code>import android.nfc.Tag;
  import android.os.Bundle;
  import android.os.PersistableBundle;
  import android.support.v4.app.Fragment;
  import android.support.v4.app.FragmentManager;
  import android.support.v4.app.FragmentPagerAdapter;
  import android.support.v4.view.ViewPager;
  import android.support.v7.app.ActionBarActivity;
  import android.support.v7.widget.Toolbar;
  import android.util.Log;
  
  import it.neokree.materialtabs.MaterialTab;
  import it.neokree.materialtabs.MaterialTabHost;
  import it.neokree.materialtabs.MaterialTabListener;
  
  public class MyCloud extends ActionBarActivity implements MaterialTabListener{
  
      private Toolbar toolbar;
  
      private MaterialTabHost tabHost;
      private ViewPager viewPager;
  
      @Override
      public void onCreate(Bundle savedInstanceState) {
  
          super.onCreate(savedInstanceState);
  
          setContentView(R.layout.mycloud);
  
          toolbar = (Toolbar) findViewById(R.id.tool_bar);
          setSupportActionBar(toolbar);
          getSupportActionBar().setDisplayHomeAsUpEnabled(true);
  
      }
  
  }
  </code></pre>
  
  <p>I get the following error via Logcat :</p>
  
  <pre><code>3-19 22:47:33.183  29878-29878/uk.co.noteu E/AndroidRuntime﹕ FATAL EXCEPTION: main
      Process: uk.co.noteu, PID: 29878
      java.lang.RuntimeException: Unable to start activity ComponentInfo{uk.co.noteu/uk.co.noteu.MyCloud}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.support.v7.widget.Toolbar.getTitle()' on a null object reference
              at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2314)
              at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2388)
              at android.app.ActivityThread.access$800(ActivityThread.java:148)
              at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292)
              at android.os.Handler.dispatchMessage(Handler.java:102)
              at android.os.Looper.loop(Looper.java:135)
              at android.app.ActivityThread.main(ActivityThread.java:5312)
              at java.lang.reflect.Method.invoke(Native Method)
              at java.lang.reflect.Method.invoke(Method.java:372)
              at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901)
              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:696)
       Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.support.v7.widget.Toolbar.getTitle()' on a null object reference
              at android.support.v7.internal.widget.ToolbarWidgetWrapper.&lt;init&gt;(ToolbarWidgetWrapper.java:95)
              at android.support.v7.internal.widget.ToolbarWidgetWrapper.&lt;init&gt;(ToolbarWidgetWrapper.java:88)
              at android.support.v7.internal.app.ToolbarActionBar.&lt;init&gt;(ToolbarActionBar.java:82)
              at android.support.v7.app.ActionBarActivityDelegateBase.setSupportActionBar(ActionBarActivityDelegateBase.java:189)
              at android.support.v7.app.ActionBarActivity.setSupportActionBar(ActionBarActivity.java:92)
              at uk.co.noteu.MyCloud.onCreate(MyCloud.java:35)
              at android.app.Activity.performCreate(Activity.java:5953)
              at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1128)
              at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2267)
              at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2388)
              at android.app.ActivityThread.access$800(ActivityThread.java:148)
              at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1292)
              at android.os.Handler.dispatchMessage(Handler.java:102)
              at android.os.Looper.loop(Looper.java:135)
              at android.app.ActivityThread.main(ActivityThread.java:5312)
              at java.lang.reflect.Method.invoke(Native Method)
              at java.lang.reflect.Method.invoke(Method.java:372
  </code></pre>
  
  <p>The tool bar is part of a larger application but I've narrowed down the problem to that and removed all other code leaving with what's above. The code was compiled and tested like it is above.</p>