code: private OnPreferenceChangeListener createBreadCrumbElevationChangeListener() {
          return new OnPreferenceChangeListener() {
  
              @Override
              public boolean onPreferenceChange(Preference preference, Object newValue) {
                  int elevation = Integer.valueOf((String) newValue);
                  ((PreferenceActivity) getActivity()).setBreadCrumbElevation(elevation);
                  return true;
              }
  
          };
      }
docs: Creates and returns a listener, which allows to adapt the elevation of the bread crumbs, when
  the value of the corresponding preference has been changed.
  
  @return The listener, which has been created, as an instance of the type {@link
  OnPreferenceChangeListener}