public void registerPreferenceChangeListener(PreferenceChangeListener preferenceChangeListener){
  if (!mListeners.contains(preferenceChangeListener)) {
    mListeners.add(preferenceChangeListener);
  }
}

public void registerPreferenceChangeListener ( PreferenceChangeListener preferenceChangeListener ) { if ( ! mListeners . contains ( preferenceChangeListener ) ) { mListeners . add ( preferenceChangeListener ) ; } }
registers the specified listener to receive callbacks for any preference change event .
