title: PreferenceActivity with multiple PreferenceScreens without Headers
body: <p>I would like to do a normal PreferenceActivity (in the old style, without headers), but with fragments and without using <code>addPreferencesFromResource(id)</code> (because deprecation).<br>
  Right now I achieved this by putting this in my <code>onCreate</code>:</p>
  
  <pre><code>getFragmentManager().beginTransaction().replace(android.R.id.content, new PreferencesFragment()).commit();
  </code></pre>
  
  <p>And my <code>PreferencesFragment</code> looks something like this:</p>
  
  <pre><code>public static class PreferencesFragment extends PreferenceFragment {
      @Override
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          addPreferencesFromResource(R.xml.preferences);
      }
  }
  </code></pre>
  
  <p>Obviously I also implemented the <code>isValidFragment</code> method:</p>
  
  <pre><code>@Override
  protected boolean isValidFragment(String fragmentName) {
      return PreferencesFragment.class.getName().equals(fragmentName)
              || InnerFragment.class.getName().equals(fragmentName);
  }
  </code></pre>
  
  <p>And it's working just fine. However, there is a problem when having <code>PreferenceScreen</code>'s inside my <code>preferences.xml</code>:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      &lt;!--  ...  --&gt;
      &lt;PreferenceScreen android:fragment="net.chaozspike.batterynotifier.SettingsActivity$InnerFragment"
          android:summary="@string/settings_activity_prefs_display_night_mode_sum"
          android:title="@string/settings_activity_prefs_display_night_mode" /&gt;
      &lt;!--  ...  --&gt;
  &lt;/PreferenceScreen&gt;
  </code></pre>
  
  <p>I have the following problem: the new preference screen shows on top of the normal one, and I know it's probably because I replaced the default <code>R.id.content</code>. Screenshot:</p>
  
  <p><img src="https://i.stack.imgur.com/Lc1Hi.png" alt="screenshot not loding"></p>
  
  <p>However I want to fix this problem without using deprecated stuff or headers. Is that possible to achieve?</p>