title: ViewPagerIndicator doesn't show underline in Tab (Help)
body: <p>I want to make simple TabPagerIndicator, but It doesn't show a underline, I use xml to change the style. This is my xml style file:</p>
  
  <pre><code>&lt;!-- Application theme. --&gt;
  &lt;style name="AppTheme" parent="@style/Theme.AppCompat.Light"&gt;
      &lt;item name="vpiTitlePageIndicatorStyle"&gt;@style/CustomTitlePageIndicator&lt;/item&gt;
      &lt;item name="vpiUnderlinePageIndicatorStyle"&gt;@style/CustomUnderlinePageIndicator&lt;/item&gt; 
      &lt;item name="vpiTabPageIndicatorStyle"&gt;@style/CustomTabPageIndicator&lt;/item&gt;
  &lt;/style&gt;
  
  &lt;style name="CustomTabPageIndicator" parent="Widget.TabPageIndicator"&gt;
      &lt;item name="android:background"&gt;@color/fondo_activity&lt;/item&gt;
      &lt;item name="android:textAppearance"&gt;@style/CustomTabPageIndicator.Text&lt;/item&gt;
      &lt;item name="android:textColor"&gt;#FF555555&lt;/item&gt;
      &lt;item name="android:textSize"&gt;14sp&lt;/item&gt;
      &lt;item name="android:dividerPadding"&gt;10dp&lt;/item&gt;
      &lt;item name="showDividers"&gt;middle&lt;/item&gt; 
      &lt;item name="android:paddingLeft"&gt;8dp&lt;/item&gt;
      &lt;item name="android:paddingRight"&gt;8dp&lt;/item&gt;
      &lt;item name="android:fadingEdge"&gt;horizontal&lt;/item&gt;
      &lt;item name="android:fadingEdgeLength"&gt;8dp&lt;/item&gt;
  &lt;/style&gt;
  
  &lt;style name="CustomTabPageIndicator.Text" parent="android:TextAppearance.Medium"&gt;
      &lt;item name="android:typeface"&gt;monospace&lt;/item&gt;
  &lt;/style&gt;
  
  &lt;style name="CustomUnderlinePageIndicator"&gt;
      &lt;item name="selectedColor"&gt;#FFCC0000&lt;/item&gt;
      &lt;item name="android:background"&gt;#FFCCCCCC&lt;/item&gt;
      &lt;item name="fadeLength"&gt;1000&lt;/item&gt;
      &lt;item name="fadeDelay"&gt;1000&lt;/item&gt;
  &lt;/style&gt;
  
  
  &lt;style name="CustomTitlePageIndicator"&gt;
      &lt;item name="android:background"&gt;#18FF0000&lt;/item&gt;
      &lt;item name="footerColor"&gt;#FFAA2222&lt;/item&gt;
      &lt;item name="footerLineHeight"&gt;1dp&lt;/item&gt;
      &lt;item name="footerIndicatorHeight"&gt;3dp&lt;/item&gt;
      &lt;item name="footerIndicatorStyle"&gt;underline&lt;/item&gt;
      &lt;item name="android:textColor"&gt;#AA000000&lt;/item&gt;
      &lt;item name="selectedColor"&gt;#FF000000&lt;/item&gt;
      &lt;item name="selectedBold"&gt;true&lt;/item&gt;
  &lt;/style&gt;
  </code></pre>
  
  <p>In this picture you can see how it is shown (the red line on the top is part of the action bar)
  <img src="https://i.stack.imgur.com/rUg3N.jpg" alt="enter image description here"></p>
  
  <p>Does anyone knows where is the error and How can I solve it?</p>
  
  <p>Best.</p>