private void initDefaultNavigationPreferences() {

        final List<NavigationAppFactory.NavigationAppsEnum> apps = NavigationAppFactory.getInstalledDefaultNavigationApps();

        final CharSequence[] entries = new CharSequence[apps.size()];
        final CharSequence[] values = new CharSequence[apps.size()];
        for (int i = 0; i < apps.size(); ++i) {
            entries[i] = apps.get(i).toString();
            values[i] = String.valueOf(apps.get(i).id);
        }

        final ListPreference defaultNavigationTool = findPreference(getString(R.string.pref_defaultNavigationTool));
        defaultNavigationTool.setEntries(entries);
        defaultNavigationTool.setEntryValues(values);
        final ListPreference defaultNavigationTool2 = findPreference(getString(R.string.pref_defaultNavigationTool2));
        defaultNavigationTool2.setEntries(entries);
        defaultNavigationTool2.setEntryValues(values);
    }
Fill the choice list for default navigation tools.
main/src/main/java/cgeo/geocaching/settings/fragments/PreferenceNavigationFragment.java