title: Using Android preferences and dont show a variable to user
body: <p>I have a sharedPreferences implementation where I store user preferences. When the user clicks "preferences" in menu, I open the standar editor to allow the user to change preferences. This is the code:</p>
  
  <pre><code>@Override
  public boolean onOptionsItemSelected(MenuItem item) {
  
      switch (item.getItemId()) {
      case R.id.MENU_PREFERENCES:
          Intent intent = new Intent(context, PreferencesActivity.class);
          startActivity(intent);
          return true;
      case xx:
                  ....
      }
      Toast.makeText(this, "ERROR: Bad menu item", Toast.LENGTH_SHORT).show();
      return true;
  }
  </code></pre>
  
  <p>In PreferencesActivity.java I have:</p>
  
  <pre><code>public class PreferencesActivity extends PreferenceActivity {
      @Override
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          addPreferencesFromResource(R.xml.preferences);
      }
  
  
  
  }
  </code></pre>
  
  <p>My question is if can I have a variable in the preferences for internal use, I mean, that will not be showed to user when startActivity(intent)? how?</p>
  
  <p>I suppose I must change something in preferences.xml but dont know exactly what....</p>
  
  <p>thanks</p>
  
  <p>EDIT: as requested, I paste xml:</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;PreferenceCategory&gt;
          &lt;ListPreference android:title="Pomodoro duration" android:key="pomodoro_duration" android:summary="Duration of each pomodoro" android:entryValues="@array/array_duration_values" android:defaultValue="25" android:entries="@array/array_duration"/&gt;&lt;ListPreference android:key="short_break_duration" android:title="Short break duration" android:summary="Duration of break after each pomodoro" android:entryValues="@array/array_duration_values" android:entries="@array/array_duration" android:defaultValue="5"/&gt;
          &lt;ListPreference android:title="Long break interval" android:summary="Interval of the longer break" android:key="intervalos" android:entryValues="@array/interval_array_values" android:defaultValue="4" android:entries="@array/interval_array"/&gt;
          &lt;ListPreference android:defaultValue="20" android:title="Long break duration" android:summary="Duration of break after each pomodoro" android:key="long_break_duration" android:entries="@array/array_duration" android:entryValues="@array/array_duration_values"/&gt;&lt;RingtonePreference android:title="Notification sound" android:ringtoneType="notification" android:summary="Tone that will sound after pomodoro ends" android:key="notification_tone" android:showDefault="true" android:showSilent="true"/&gt;
          &lt;ListPreference android:summary="Period used to calculate productivity" android:title="Calculus period" android:key="calculus_period" android:entryValues="@array/array_calculo_valores" android:entries="@array/array_calculo"/&gt;
        &lt;/PreferenceCategory&gt;
  
  &lt;/PreferenceScreen&gt;
  </code></pre>
  
  <p>When I inveke the standar UI to allow user to set this variables, I would like to hide one of them programmaticaly. Is possible?</p>