title: Android TabLayout overlapping the Fragment's content
body: <p>I'm trying to make an activity with TabLayout and Viewpager.<br>
  My problem is that the TabLayout overlaps the top of the Viewpager, so the full content isn't visible.</p>
  
  <p><a href="http://i.stack.imgur.com/Twse9.jpg" rel="noreferrer">The original image</a><br>
  <a href="http://i.stack.imgur.com/1ifjh.jpg" rel="noreferrer">The result</a></p>
  
  <pre><code>&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"&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/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.TabLayout
              android:id="@+id/tabs"
              android:layout_width="match_parent"
              android:layout_height="?attr/actionBarSize"
              app:tabMode="fixed"
              app:tabGravity="fill"/&gt;
      &lt;/android.support.design.widget.AppBarLayout&gt;
  
      &lt;android.support.v4.view.ViewPager
          xmlns:android="http://schemas.android.com/apk/res/android"
          android:id="@+id/view_pager"
          android:layout_width="match_parent"
          android:layout_height="match_parent" /&gt;
  
      &lt;android.support.design.widget.FloatingActionButton
          android:id="@+id/fab"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_gravity="bottom|end"
          android:layout_margin="@dimen/fab_margin"
          android:src="@drawable/ic_add_white_24dp"/&gt;
  
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>What can I do to make my fragment begin right below the tabs?  </p>