FlutterArtist Sort DropdownSortPanel Example

class CountryInfo { 
  String id; 
  String name; 
  String nameInEnglish; 
  String countryCode; 
  String isoCode2; 
  String isoCode3; 
  int population; 
  int area; 
  double? gdp;
}

SortModel<ITEM>? get clientSideSortModel;

SortModel<ITEM>? get serverSideSortModel;

class Country12aSortModelBuilder extends SortModelBuilder<CountryInfo> {
  Country12aSortModelBuilder({
    required super.clientSideSortMode,
    required super.serverSideSortMode,
  });

  @override
  SortModelStructure defineSortModelStructure() {
    return SortModelStructure(
      sortCriterionDefs: [
        SortCriterionDef(
          criterionName: 'nameInEnglish',
          text: 'Name In English',
          translationKey: "country.nameInEnglish",
        ),
        SortCriterionDef(
          criterionName: 'population',
          text: 'Population',
          translationKey: "country.population",
          serverSideConfig: SortCriterionConfig(
            initialSortDirection: SortDirection.desc,
          ),
        ),
        SortCriterionDef(
          criterionName: 'area',
          text: 'Area',
          translationKey: "country.area",
          serverSideConfig: SortCriterionConfig(
            initialSortDirection: SortDirection.asc,
          ),
        ),
      ],
    );
  }

  @override
  Comparable? getComparisonValue({
    required CountryInfo item,
    required String criterionName,
  }) {
    if (criterionName == "nameInEnglish") {
      return item.nameInEnglish;
    } else if (criterionName == "population") {
      return item.population;
    } else if (criterionName == "area") {
      return item.area;
    }
    return null;
  }

  @override
  String? getTranslationText({required String translationKey}) {
    return null;
  }
}

class Country12aShelf extends Shelf {
  @override
  ShelfStructure defineShelfStructure() {
    return ShelfStructure(
      filterModels: {},
      blocks: [
        Country12aBlock(
          name: Country12aBlock.blkName,
          description: null,
          config: BlockConfig(
            pageable: Pageable(pageSize: 5),
            clientSideSortStrategy: SortStrategy.modelBased,
          ),
          filterModelName: null,
          formModel: null,
          childBlocks: [],
          sortModelBuilder: Country12aSortModelBuilder(
            clientSideSortMode: SortMode.single,
            serverSideSortMode: SortMode.single,
          ),
        ),
      ],
    );
  }

  Country12aBlock findCountry12aBlock() {
    return findBlock(Country12aBlock.blkName) as Country12aBlock;
  }
}

BlockConfig(
  ...
  clientSideSortStrategy: SortStrategy.modelBased,
),

if (country12aBlock.serverSideSortModel != null)
  DropdownSortPanel.simple(
    sortModel: country12aBlock.serverSideSortModel!,
  ),

if (country12aBlock.clientSideSortModel != null)
  DropdownSortPanel.simple(
    sortModel: country12aBlock.clientSideSortModel!,
  ),

Future<void> _clearCriteria() async {
  await serverSideSortModel.clearAllSorts();
}

class Country12aBlock
    extends
        Block<
          String, //
          CountryInfo,
          CountryData,
          EmptyFilterInput,
          EmptyFilterCriteria,
          EmptyFormInput,
          EmptyAdditionalFormRelatedData
        > {
  static const blkName = "country12a-block";

  final countryRestProvider = CountryRestProvider(); 
  
  @override
  Future<ApiResult<PageData<CountryInfo>?>> performQuery({
    required Object? parentBlockCurrentItem,
    required EmptyFilterCriteria filterCriteria,
    required SortableCriteria sortableCriteria,
    required Pageable pageable,
  }) async {
    return await countryRestProvider.query(
      sortableCriteria: sortableCriteria,
      pageable: pageable,
    );
  } 
  ...
}

print(sortableCriteria.toSignedString());

// Output:
//  +criterion1,-criterion2


print(sortableCriteria.toJsonString());

// Output:
//  {"criterion1": "asc", "criterion2": "desc"}

...
Future<ApiResult<CountryInfoPage>> query({
  required Pageable pageable,
  SortableCriteria? sortableCriteria,
  String? searchText,
}) async {
  Map<String, dynamic>? queryParameters = {
    "currentPage": pageable.page,
    "pageSize": pageable.pageSize,
    "searchText": searchText,
    // Json String: '{"criterion1": "asc", "criterion2": "desc"}'.
    "jsonSortableCriteria": sortableCriteria?.toJsonString(),
  };

  // /rest/countryInfoPage
  ApiResult<CountryInfoPage> result = await flutterArtistDio.jsonGet(
    "/rest/countryInfoPage",
    queryParameters: queryParameters,
    converter: CountryInfoPage.fromMap,
  );
  return result;
}