title: android.support.v7.widget.Toolbar not listing in AppCompat library
body: <p>I want to working with Toolbar.</p>
  
  <p>I have the following layout file for customizing the Toolbar.</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"
  android:layout_width="match_parent"
  android:layout_height="match_parent" &gt;
  
  &lt;LinearLayout
      android:id="@+id/music_actionbar_display_home"
      android:layout_width="wrap_content"
      android:layout_height="match_parent"
      android:layout_marginRight="2dp"
      android:orientation="horizontal"
      android:weightSum="2" &gt;
  
      &lt;ImageView
          android:id="@+id/music_actionbar_backbutton"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_gravity="center"
          android:layout_marginRight="2dp"
          android:layout_weight="1"
          android:src="@drawable/home_back" /&gt;
  
      &lt;ImageView
          android:id="@+id/music_actionbar_logo"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_gravity="center"
          android:layout_weight="1"
          android:src="@drawable/home_square_logo" /&gt;
  &lt;/LinearLayout&gt;
  
  &lt;Spinner
      android:id="@+id/music_actionbar_language"
      android:layout_width="wrap_content"
      android:layout_height="match_parent"
      android:layout_alignParentTop="true"
      android:layout_centerHorizontal="true"
      android:layout_marginLeft="5dp"
      android:layout_toRightOf="@+id/music_actionbar_display_home"
      android:drawSelectorOnTop="true"
      android:spinnerMode="dialog" /&gt;
  </code></pre>
  
  <p></p>
  
  <p>But in Graphical Layout I am getting the following error message.</p>
  
  <p><strong>Exception raised during rendering: com.android.layoutlib.bridge.MockView cannot be cast to android.view.ViewGroup
  Exception details are logged in Window > Show View > Error Log
  The following classes could not be instantiated:
  - android.support.v7.widget.Toolbar (Open Class, Show Error Log)
  See the Error Log (Window > Show View) for more details.</strong></p>
  
  <p>In Appcompat library I don't have the class android.support.v7.widget.Toolbar.
  And in my SDK Manager I have installed the <strong>Android Support Library</strong> and <strong>Android Support Repository</strong> upto date.</p>
  
  <p>See the image below.</p>
  
  <p><img src="https://i.stack.imgur.com/NdvKR.jpg" alt="enter image description here">
  What should I have to do to have the Toolbar class?.</p>
  
  <p>If need more details other than given above, I will.</p>