ios - Exception while registering subclass with Parse -

i have class called attendee inherits pfobject. in applicationdidfinishlaunching() method, register subclass so:

func application(application: uiapplication, didfinishlaunchingwithoptions launchoptions: [nsobject: anyobject]?) -> bool {     attendee.initialize()     parse.enablelocaldatastore()     parse.setapplicationid(objectmanager.appid, clientkey: objectmanager.clientkey)      getdata()      return true }  func getdata() {     //create query     var attendeequery = attendee.query()     attendeequery?.fromlocaldatastore()         .frompinwithname(cachekeys.attendeeskey)         .wherekey("conference", equalto: objectmanager.currentconf)      //register background task     var bgtask = uibackgroundtaskinvalid     bgtask = uiapplication.sharedapplication().beginbackgroundtaskwithexpirationhandler({ () -> void in         uiapplication.sharedapplication().endbackgroundtask(bgtask)         bgtask = uibackgroundtaskinvalid          println("attendees loader expiration handler called")     })      //run query     attendeequery?.findobjectsinbackgroundwithblock({ (cachedattendees: [anyobject]?, error:nserror?) -> void in         if error != nil {             println(error)             return         }          ...              uiapplication.sharedapplication().endbackgroundtask(bgtask)         })     }) } 

however, when run code, exception @ line var attendeequery = attendee.query(). exception says need register attendee subclass before use it. don't understand why saying that, register right beforehand. below attendee class definition.

class attendee: pfobject, pfsubclassing {      var name:string         {             return self["name"] as! string     }      ...       override class func initialize() {         var oncetoken : dispatch_once_t = 0;         dispatch_once(&oncetoken) {             self.registersubclass()         }     }      class func parseclassname() -> string {         return classes.attendee     } } 

the exception:

*** terminating app due uncaught exception 'nsinternalinconsistencyexception', reason: 'the class medconf.attendee must registered registersubclass before using parse.' *** first throw call stack: (0x1835002d8 0x194d240e4 0x183500218 0x1001e21d0 0x1001e1fac 0x100135d88 0x100138af0 0x1000e43e0 0x1000e4580 0x187fb3190 0x1881ca854 0x1881cd208 0x1881cb778 0x18bd093c8 0x1834b827c 0x1834b7384 0x1834b59a8 0x1833e12d4 0x187fac43c 0x187fa6fac 0x1000e7b48 0x1953a2a08) 

i had same problem when upgraded parse's ios sdk 1.7.5 1.6.3. problem in initialize function, looked same yours.

using dispatch_once_t local var in function doesn't serve purpose of ensuring subclass registered once; noticed putting breakpoint on registersubclass() call in initialize function being called many times. constant re-registering of subclass apparently causing problems new version of parse sdk.

changing initialize function fixed problem:

private static var oncetoken : dispatch_once_t = 0  override class func initialize() {     dispatch_once(&oncetoken) {         self.registersubclass()     } }