ios - Why isn't core data maintaining persistance in this code? -

this code

+(favouritesmodel *) savefavourites: (nsstring *) title and: (nsstring *) subtitle{  favouritesmodel *savedata = [[favouritesmodel alloc] init]; savedata.context = [savedata managedobjectcontext]; nsmanagedobject *task = [[favourites alloc] initwithcontext:savedata.context];  [task setvalue:title forkey:@"title"]; [task setvalue:subtitle forkey:@"subtitle"];  nsstring *titlestr = [task valueforkey:@"title"]; nsstring *subtitlestr = [task valueforkey:@"subtitle"];  [savedata.favouritesdata addobject:titlestr]; [savedata.favouritesdata addobject:subtitlestr];  appdelegate *appdelegate; [appdelegate savecontext];  return savedata; } 

the data want saved it's not persisting. i've used savecontext() method in "applicationwillterminate" in app delegate too. still if i'm quitting , reopening app, data not there.

edit i'm using model class call method in 5 classes.

what have add implement data persistence ?

put breakpoint on second of these lines

appdelegate *appdelegate; [appdelegate savecontext]; // <----- here 

appdelegate not being set correctly , breakpoint confirm this.

it needs set [something] this:

// untested appdelegate = (appdelegate*)[[uiapplication sharedapplication] delegate];