iphone GData spreadsheet unrecognized selector

I've used the GData spreadsheets code for MAC to write a corresponding iPhone version (the same code), but I get a exception thrown: [GDataEntryBase worksheetsFeedURL]: unrecognized selector sent to instance ... It appears to me that when fetchi开发者_StackOverflow中文版ng the entries from the spreadsheet feed, I got a array of GDataEntryBase (iPhone version) instead of GDataEntrySpreadsheet. Any help will be highly appreciated!

Thank you.

The base class is created when the needed subclasses aren't compiled and linked into the application.

Be sure the -ObjC linker flag is set for your project, and that -DGDATA_REQUIRE_SERVICE_INCLUDES=1 and -DGDATA_INCLUDE_SPREADSHEET_SERVICE=1 are defined for the target that includes the spreadsheet classes. ( in GData.xcodeproj > Build Settings > Other Linker Flags )

These are discussed on the BuildingTheLibrary wiki page for the project.