title: File picker dialog in PreferenceFragment
body: <p>I want to get a pick file dialog in my PreferenceActivity how do I get to that? Can I override onClick for PreferenceActivity somehow? Android API 14. </p>
  
  <p>Here's my PreferensActivity: </p>
  
  <pre><code>    import android.preference.PreferenceActivity;
      import java.util.List;
  public class SettingsActivity extends PreferenceActivity {
  
  @Override
  public boolean onIsMultiPane() {
      return true;
  }
  
  public void onBuildHeaders(List&lt;Header&gt; target) {
          loadHeadersFromResource(R.xml.pref_head, target);
      }
  }
  </code></pre>
  
  <p>Header xml is:</p>
  
  <pre><code>    &lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;preference-headers
  xmlns:android="http://schemas.android.com/apk/res/android"&gt;
  &lt;header
      android:fragment="com.bfx.rfid.FragmentSetApp"
      android:icon="@android:drawable/ic_menu_call"
      android:title="Application"
      android:summary="Application settings"&gt;
  &lt;/header&gt;
  &lt;header
      android:fragment="com.bfx.rfid.FragmentSetConnection"
      android:icon="@android:drawable/ic_menu_call"
      android:title="Connectivity"
      android:summary="Connection settings"&gt;
  &lt;/header&gt;
  &lt;/preference-headers&gt;
  </code></pre>
  
  <p>PreferenceFragment class:</p>
  
  <pre><code>import android.os.Bundle;
  import android.preference.PreferenceFragment;
  
  public class FragmentSetApp extends PreferenceFragment {
  
  public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
      addPreferencesFromResource(R.xml.fragment_set_app);
    }
  }
  </code></pre>
  
  <p>PreferenceFragment xml is:</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;Preference
      android:key="work_directory"
      android:title="Folder to work with"&gt;
  &lt;/Preference&gt;
  &lt;PreferenceCategory
      android:title="Work with a database file"&gt;
      &lt;CheckBoxPreference
          android:key="DB_default"
          android:summary="Choose a default database file or pick one"
          android:title="Choose a database file"
          android:defaultValue="true"/&gt;
      &lt;EditTextPreference
          android:key="DB_URI"
          android:title="Database file"
          android:dependency="DB_default"&gt;
      &lt;/EditTextPreference&gt;
  &lt;/PreferenceCategory&gt;
  &lt;/PreferenceScreen&gt;
  </code></pre>