title: Android Action Bar Fill Tab Width
body: <p>I have included a progress bar in each of my Action Bar tabs using a custom view.  I would like the width of the progress bar to match the width of the tab indicator.  However, the area covered by the custom view has margins set within the tab, so I'm unable to extend the progress bar to the full tab width. What's the best way to make this work?</p>
  
  <p>Below is what it looks like now...</p>
  
  <p><img src="https://i.imgur.com/mp7ee.png" alt="progress bar in tab"></p>
  
  <p>The progress bar is set to match the parent width. </p>
  
  <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="match_parent"
  android:layout_margin="0dp"
  &gt;
          &lt;TextView xmlns:android="http://schemas.android.com/apk/res/android"
          android:id="@+id/tab_title"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:text = "Day 1"
          android:textAllCaps="true"
          android:textStyle="bold"
          android:textSize="13dp"
          android:layout_gravity="center"
          android:gravity="center"
          android:paddingTop="18dp"
          /&gt;
  
          &lt;ProgressBar 
              style="@android:style/Widget.Holo.ProgressBar.Horizontal"
              android:id="@+id/tab_progress"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:layout_alignParentBottom="true"
              android:layout_marginBottom="1dp"
              /&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>