title: SlidingTabLayout error
body: <p>When I try to add <em>SlidingTabLayout</em> in xml file it gets me an error</p>
  
  <pre><code>&lt;android.support.v4.widget.DrawerLayout
  
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/DrawerLayoutTop"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:elevation="7dp"&gt;
  
  &lt;LinearLayout
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:orientation="vertical"&gt;
  
      &lt;include
          android:id="@+id/tool_bar"
          layout="@layout/tool_bar"&gt;
      &lt;/include&gt;
  
      &lt;com.android4devs.slidingtab.SlidingTabLayout
          android:id="@+id/tabs"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:elevation="2dp"
          android:background="@color/ColorPrimary"/&gt;
  
      &lt;android.support.v4.view.ViewPager
          android:id="@+id/pager"
  
          android:layout_height="match_parent"
          android:layout_width="match_parent"
          android:layout_weight="1"
          &gt;&lt;/android.support.v4.view.ViewPager&gt;
  
  &lt;/LinearLayout&gt;
  
  &lt;android.support.v7.widget.RecyclerView
      android:id="@+id/RecyclerView"
      android:layout_width="320dp"
      android:layout_height="match_parent"
      android:layout_gravity="left"
      android:background="#ffffff"
      android:scrollbars="vertical"&gt;
  
  &lt;/android.support.v7.widget.RecyclerView&gt;
  </code></pre>
  
  <p>
  Here is the logcat</p>
  
  <p>Caused by: java.lang.ClassNotFoundException: Didn't find class "com.android4devs.slidingtab.SlidingTabLayout" on path: DexPathList[[zip file "/data/app/com.example.myapplication-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.myapplication-1, /vendor/lib, /system/lib]]</p>
  
  <p>How can I correct it?</p>