App Crash: NSInvalidArgumentException - iphone

Question

[__NSArrayM relatedObjectDidChange]: unrecognized selector sent to instance
error Class: NSInvalidArgumentException
the crash report stackTrace:
0 CoreFoundation 0x33d153e7 <redacted> + 162
1 libobjc.A.dylib 0x3ba06963 objc_exception_throw + 30
2 CoreFoundation 0x33d18f31 <redacted> + 0
3 CoreFoundation 0x33d1764d <redacted> + 392
4 CoreFoundation 0x33c6f208 _CF_forwarding_prep_0 + 24
5 EventKit 0x3440af03 <redacted> + 30
6 EventKit 0x34410225 <redacted> + 396
7 EventKit 0x34410095 <redacted> + 28
8 EventKit 0x3440d3fd <redacted> + 396
9 Calendar 0x000f10a5 -[createNewEventView editEvent:] + 1696
10 UIKit 0x35c0f087 <redacted> + 70
11 UIKit 0x35c0f111 <redacted> + 120
12 UIKit 0x35c0f087 <redacted> + 70
13 UIKit 0x35c0f03b <redacted> + 30
14 UIKit 0x35c0f015 <redacted> + 44
15 UIKit 0x35c0e8cb <redacted> + 502
16 UIKit 0x35c0edb9 <redacted> + 488
17 UIKit 0x35b375f9 <redacted> + 524
18 UIKit 0x35b248e1 <redacted> + 380
19 UIKit 0x35b241ef <redacted> + 6198
20 GraphicsServices 0x3783b5f7 <redacted> + 590
21 GraphicsServices 0x3783b227 <redacted> + 34
22 CoreFoundation 0x33cea3e7 <redacted> + 34
23 CoreFoundation 0x33cea38b <redacted> + 138
24 CoreFoundation 0x33ce920f <redacted> + 1382
25 CoreFoundation 0x33c5c23d CFRunLoopRunSpecific + 356
26 CoreFoundation 0x33c5c0c9 CFRunLoopRunInMode + 104
27 GraphicsServices 0x3783a33b GSEventRunModal + 74
28 UIKit 0x35b782b9 UIApplicationMain + 1120
29 Calendar 0x000a9bbf main + 66
30 Calendar 0x0003a600 start + 40
What does such error means, and what is the possibilities for such error?
My implementation of editEvent method:
-(void) editEvent:(EKSpan )span
{
EKEvent * newEditingEvent = self.EventToEdit;
CalendarAppDataObject* theDataObject = [self theAppDataObject];
if(eventCalendar != nil && theDataObject.selectedCalendarsForDisplayData != nil){
NSArray *arrayDataUnarchiver =(NSArray *) [NSKeyedUnarchiver unarchiveObjectWithData:theDataObject.selectedCalendarsForDisplayData];
NSMutableSet * uniqueId = [[NSMutableSet alloc ] initWithArray:arrayDataUnarchiver];
[uniqueId addObject:eventCalendar.calendarIdentifier];
NSArray * selectedCal = [uniqueId allObjects];
NSData *arrayDataArchiver = [NSKeyedArchiver archivedDataWithRootObject:selectedCal];
theDataObject.selectedCalendarsForDisplayData = arrayDataArchiver;
//save selected to database
NSError *error;
self.managedObjectContext = theDataObject.managedObjectContext;
NSManagedObjectContext *context = [self managedObjectContext];
// **** log objects currently in database ****
// create fetch object, this objects fetch's the objects out of the database
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Settings" inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSArray *fetchedObjects= [context executeFetchRequest:fetchRequest error:&error] ;
for (NSManagedObject *info in fetchedObjects)
{
[info setValue:arrayDataArchiver forKey:#"selectedCalendarsForDisplayData"] ;
}
//this is for comitting changes to core data
[context save:&error];
[fetchRequest release];
[uniqueId release];
}
NSString * eventNotesString = #"";
if(self.eventNotes != nil)
{
eventNotesString = self.eventNotes;
}
newEditingEvent.notes = [EventsDataUtil generateEventsNoteForSavingColor:eventNotesString colorToSave:self.eventBackColor];
if(self.eventRecurrenceRule != nil)
{
NSArray * RecRulesArray = [[[NSArray alloc ] initWithObjects:self.eventRecurrenceRule, nil]autorelease];
if(theDataObject.isRepeatChanged)
{
[newEditingEvent setRecurrenceRules:RecRulesArray];
}
}else
{
[newEditingEvent setRecurrenceRules:nil];
}
if([[ self.eventTitle stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] isEqualToString:#""])
{
self.eventTitle = #"New Event";
}
newEditingEvent.title = self.eventTitle;
if(isLocationPhoneNumber)
{
NSString * PhoneLocationString = #"tel:";
PhoneLocationString = [PhoneLocationString stringByAppendingFormat:#"%#", [self.contactPhoneNumber stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]]];
newEditingEvent.location = PhoneLocationString;
}
else
{
newEditingEvent.location = self.eventLocation;
}
newEditingEvent.startDate = self.eventStartDate;
newEditingEvent.endDate =self.eventEndDate;
newEditingEvent.allDay = self.eventAllDay;
newEditingEvent.calendar = self.eventCalendar;
newEditingEvent.URL = self.eventURL;
// repeat and alert
NSArray * Alarms = nil;
if(self.eventAlert !=nil)
{
if(self.eventSecondAlert !=nil)
{
Alarms = [[[NSArray alloc] initWithObjects:self.eventAlert,self.eventSecondAlert, nil]autorelease];
}
else {
Alarms = [[[NSArray alloc] initWithObjects:self.eventAlert, nil]autorelease];
}
}
newEditingEvent.alarms = Alarms;
NSError *err;
[newEditingEvent setCalendar:self.eventCalendar];
[sharedEventStore saveEvent:newEditingEvent span:span commit:YES error:&err];
theDataObject.needUpdate = YES;
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
[[NSNotificationCenter defaultCenter] postNotificationName:#"dismissEventDetails" object:nil];
}
else{
[self dismissViewControllerAnimated:YES completion:NULL];
}
}

Answer 1

The error report tells you everything you need to know:
[__NSArrayM relatedObjectDidChange]: unrecognized selector sent to instance
Which means that the NSArray class does not have a method called relatedObjectDidChange, so your code obviously calls this somewhere:
[someArray relatedObjectDidChange];
Without seeing your code, I cannot provide more help. I'd like to see this method:
[createNewEventView editEvent:]
and the definition of that class

Answer 2

The method relatedObjectDidChange is sent to an object of class NSArray which the class does not respond to. Did you mix up an NSMutableArray with an NSArray somewhere?
Or is relatedObjectDidChange a method that you did implement yourself on one of your objects? In that case you probably assigned an NSArray to a variable of which you expect to be of your very own class.