title: No elevation For FloatingActionButton ( FAB ) in Support Material Design
body: <p>With the help of <a href="https://stackoverflow.com/questions/30576450/floatingactionbutton-example-with-support-library">this question</a> I built a Floating Action Button to add elements to my Listview</p>
  
  <p>The code is easy:</p>
  
  <pre><code>&lt;android.support.design.widget.FloatingActionButton
      android:id="@+id/fab"
      app:backgroundTint="@color/spg_rosa"
      app:borderWidth="0dp"
      app:elevation="4dp"
      app:fabSize="normal"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:src="@drawable/ic_add_white_48dp"
      android:layout_alignParentBottom="true"
      android:layout_alignParentRight="true"
      android:layout_alignParentEnd="true"
      /&gt;
  </code></pre>
  
  <p>The thing is         </p>
  
  <pre><code>app:elevation="4dp"
  </code></pre>
  
  <p>is not working, I can't see any shadow!</p>
  
  <p>I grab the icon from Google : <a href="https://www.google.com/design/icons/" rel="nofollow noreferrer">https://www.google.com/design/icons/</a></p>
  
  <p>Any idea?</p>
  
  <p>EDIT: I'm using it in Samsung S3 Mini ( API 16 )</p>