title: ContentLoadingProgressBar is never shows
body: <p>I've replaced in my fragment simple <code>ProgressBar</code> with <code>ContentLoadingProgressBar</code>.
  Now fragment layout looks like this: </p>
  
  <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
              style="@style/simple_match_parent_style"&gt;
  
  &lt;android.support.v4.widget.ContentLoadingProgressBar
              android:id="@+id/progress"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_centerInParent="true"/&gt;
  
  &lt;TextView
      android:id="@+id/txt_no_songs"
      android:text="@string/txt_no_songs"
      android:layout_centerInParent="true"
      style="@style/txt_no_songs"/&gt;
  
  &lt;ListView
      android:id="@+id/list"
      android:fastScrollEnabled="true"
      android:divider="@null"
      style="@style/simple_match_parent_style"/&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>I show this ProgressBar in <code>onViewCreated</code>:</p>
  
  <pre><code>@Override
  public void onViewCreated(View view, Bundle savedInstanceState) {
      super.onViewCreated(view, savedInstanceState);
      progressBar = (ContentLoadingProgressBar) view.findViewById(R.id.progress);
      progressBar.show();
      ...
  }
  </code></pre>
  
  <p>For test purpose I've removed <code>progressBar.hide()</code> call to make ProgressBar appear in any case. But the problem is that my <code>ContentLoadingProgressBar</code> is never really shown. <br/><br/>
  Should I do something else to show <code>ContentLoadingProgressBar</code>? I didn't manage to find any relevant examples of using <code>ContentLoadingProgressBar</code> so any useful examples are also desirable. Thanks in advance.</p>