Method BuildDropDownList

src/settings_gui.cpp:472–589

* Build the dropdown list for a specific widget. * @param widget Widget to build list for * @param selected_index Currently selected item * @return the built dropdown list, or nullptr if the widget has no dropdown menu. */

	 * @return the built dropdown list, or nullptr if the widget has no dropdown menu.
	 */
	DropDownList BuildDropDownList(WidgetID widget, int *selected_index) const
	{
		DropDownList list;
		switch (widget) {
			case WID_GO_CURRENCY_DROPDOWN: { // Setup currencies dropdown
				*selected_index = this->opt->locale.currency;
				uint64_t disabled = _game_mode == GM_MENU ? 0LL : ~GetMaskOfAllowedCurrencies();

				/* Add non-custom currencies; sorted naturally */
				for (const CurrencySpec &currency : _currency_specs) {
					int i = &currency - _currency_specs.data();
					if (i == CURRENCY_CUSTOM) continue;
					if (currency.code.empty()) {
						list.push_back(MakeDropDownListStringItem(currency.name, i, HasBit(disabled, i)));
					} else {
						list.push_back(MakeDropDownListStringItem(GetString(STR_GAME_OPTIONS_CURRENCY_CODE, currency.name, currency.code), i, HasBit(disabled, i)));
					}
				}
				std::sort(list.begin(), list.end(), DropDownListStringItem::NatSortFunc);

				/* Append custom currency at the end */
				list.push_back(MakeDropDownListDividerItem()); // separator line
				list.push_back(MakeDropDownListStringItem(STR_GAME_OPTIONS_CURRENCY_CUSTOM, CURRENCY_CUSTOM, HasBit(disabled, CURRENCY_CUSTOM)));
				break;
			}

			case WID_GO_AUTOSAVE_DROPDOWN: { // Setup autosave dropdown
				int index = 0;
				for (auto &minutes : _autosave_dropdown_to_minutes) {
					index++;
					if (_settings_client.gui.autosave_interval <= minutes) break;
				}
				*selected_index = index - 1;

				const StringID *items = _autosave_dropdown;
				for (uint i = 0; *items != INVALID_STRING_ID; items++, i++) {
					list.push_back(MakeDropDownListStringItem(*items, i));
				}
				break;
			}

			case WID_GO_LANG_DROPDOWN: { // Setup interface language dropdown
				for (uint i = 0; i < _languages.size(); i++) {
					bool hide_language = IsReleasedVersion() && !_languages[i].IsReasonablyFinished();
					if (hide_language) continue;
					bool hide_percentage = IsReleasedVersion() || _languages[i].missing < _settings_client.gui.missing_strings_threshold;
					std::string name;
					if (&_languages[i] == _current_language) {
						*selected_index = i;
						name = _languages[i].own_name;
					} else {
						/* Especially with sprite-fonts, not all localized
						 * names can be rendered. So instead, we use the
						 * international names for anything but the current
						 * selected language. This avoids showing a few ????
						 * entries in the dropdown list. */
						name = _languages[i].name;
					}