@Override
 public void onPreferencesChanged(SharedPreferences settings) {
   super.onPreferencesChanged(settings);
   track.maxPoints =
       Integer.parseInt(
           settings.getString(
               application.getString(R.string.pref_tracking_currentlength),
               application.getString(R.string.def_tracking_currentlength)));
 }
 public void onBeforeDestroy() {
   super.onBeforeDestroy();
   unbind();
 }