private void initOfflineRoutingPreferences() {
        DefaultFilesUtils.checkDefaultFiles();
        PreferenceUtils.setOnPreferenceChangeListener(findPreference(getString(R.string.pref_useInternalRouting)), (preference, newValue) -> {
            updateRoutingPrefs(!Settings.useInternalRouting());
            return true;
        });
        updateRoutingPrefs(Settings.useInternalRouting());
        updateRoutingProfilesPrefs();
    }
Fill the choice list for default navigation tools.
main/src/main/java/cgeo/geocaching/settings/fragments/PreferenceNavigationFragment.java