ios - Why does my app crash when I try to access a contact’s name? -

my app asks users select 1 of contacts , 1 of contact’s addresses. want generate “display name” use refer address: example, if user selects 1 of john smith’s addresses, display name “john smith” , ui refer address “john smith’s address”. algorithm extracting name address record follows:

1. if contact business, use business’s name.
2. if there first name , last name, use “firstname lastname”.
3. if there first name use first name.
4. if there last name use last name.
5. use string “selected contact”.

i have logic implemented. problem see crashes (kern_invalid_address) on 1 of 2 marked lines. app uses arc, , don’t have lot of experience core foundation, assume i’m doing memory management or bridging incorrectly. can tell me i’m doing wrong, , how fix crashes? relevant 2 methods follows:

- (bool) peoplepickernavigationcontroller:(abpeoplepickernavigationcontroller *)peoplepicker        shouldcontinueafterselectingperson:(abrecordref) person                                  property:(abpropertyid) property                                identifier:(abmultivalueidentifier) identifier {     [self dismissviewcontrolleranimated:yes completion:null];      cftyperef address = abrecordcopyvalue(person, property);     nsarray *addressarray = (__bridge_transfer nsarray *)abmultivaluecopyarrayofallvalues(address);     cfrelease(address);     nsdictionary *addressdict = [addressarray objectatindex:0];      clgeocoder *geocoder = [[clgeocoder alloc] init];     [geocoder geocodeaddressdictionary:addressdict completionhandler:^(nsarray *placemarks, nserror *error) {         if (error || !placemarks || [placemarks count] == 0) {             // tell user there error         } else {             nsstring *name = contactname(person);             nsstring *addressname = [nsstring stringwithformat:@"%@’s address", name];             // use `addressname` refer address user         }     }];      return no; }  nsstring* contactname(abrecordref person) {     nsstring *name;      // crashes occur on line:     cfnumberref contacttype = abrecordcopyvalue(person, kabpersonkindproperty);      if (contacttype == kabpersonkindorganization)         name = (__bridge_transfer nsstring *)abrecordcopyvalue(person, kabpersonorganizationproperty);      if (!name || [name length] == 0 || contacttype == kabpersonkindperson) {         // other crashes occur on line:         nsstring *firstname = (__bridge_transfer nsstring *)abrecordcopyvalue(person, kabpersonfirstnameproperty);         nsstring *lastname = (__bridge_transfer nsstring *)abrecordcopyvalue(person, kabpersonlastnameproperty);          if (firstname && [firstname length] > 0 && lastname && [lastname length] > 0)             name = [nsstring stringwithformat:@"%@ %@", firstname, lastname];         else if (firstname && [firstname length] > 0)             name = firstname;         else if (lastname && [lastname length] > 0)             name = lastname;          if (!name || [name length] == 0)             name = @"selected contact";     }      cfrelease(contacttype);      return name; } 

assuming call dismissviewcontrolleranimated:completion: dismissing people picker controller, , person object retained controller, person deallocated before finished processing it. merely moving dismissviewcontrolleranimated:completion: call end of method should fix problem. if processing causes of delay before dismissing view controller, copy person value variable arc retain you, dismiss view controller, process person.