Adding MKannotation to a mapview cause EXC_BAD_ACCESS error - ios

Question

After I updated the Core data with the right value, i would like to add these value to the map view.
This the code that a I'd wrote for doing this it's this:
-(void)updateMapWithPredicate:(NSPredicate *)predicate
{
int numberOfElementiOnMap = 0;
dispatch_async(dispatch_get_main_queue(), ^{
[self.ActiviIndicator startAnimating];
[self.mapView removeAnnotations:self.mapView.annotations];
});
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:#"Photo"];
if (predicate) {
request.predicate = [NSCompoundPredicate andPredicateWithSubpredicates:#[[NSPredicate predicateWithFormat:#"(latitude != nil) AND (longitude != nil)"]
,predicate]];
} else {
request.predicate = [NSPredicate predicateWithFormat:#"(latitude != nil) AND (longitude != nil)"];
}
//Get all different coordinate from core data.
[request setPropertiesToFetch:#[#"latitude", #"longitude"]];
[request setReturnsDistinctResults:YES];
[request setResultType:NSDictionaryResultType];
// Execute the fetch
NSError *error = nil;
NSArray *photos = [self.context executeFetchRequest:request error:&error];
for (NSDictionary *coordinateDic in photos) {
NSPredicate *predicateToSend;
if (predicate) {
/* Get all pictures that corresponding to the coordinate inside the coordinateDic
*/
predicateToSend = [NSCompoundPredicate andPredicateWithSubpredicates:#[[NSPredicate predicateWithFormat:#"(latitude == %#) AND (longitude == %#)",
[coordinateDic valueForKey:#"latitude"], [coordinateDic valueForKey:#"longitude"]],predicate]];
} else {
predicateToSend = [NSPredicate predicateWithFormat:#"(latitude == %#) AND (longitude == %#)",[coordinateDic valueForKey:#"latitude"], [coordinateDic valueForKey:#"longitude"]];
}
dispatch_async(dispatch_get_main_queue(), ^{
//get all picture with the same lautide and longitude that are specified on predicate
NSArray *photos2 = [Photo pictureFromContext:self.context withPredicate:predicateToSend];
//if the pictures are more then one, we add only one picture, and we write the number of pictures as a subtitle of the mkannotationview
if ([photos2 count] > 1) {
Photo *photo = [photos2 lastObject];
photo.photoDescription = [NSString stringWithFormat:#"album with %lu picures",(unsigned long)[photos2 count]];
if (photo) {
// [self.mapView addAnnotation:photo];
}
} else { //add the only pictures
if ([photos2 firstObject]) {
[self.mapView addAnnotation:[photos2 firstObject]];
}
}
});
}
}
On this code i basically retrieve the value that in need from core date, and then add it to the map.
The objects that I'm adding to the map are obviously conform to the <MKAnnotation> protocol. I got the error on the [self.mapView addAnnotation:[photos2 firstObject]];line. The strange fact is that some object that i get from core date are correctly added to the map. I tried to debug the code by enabling the NSZombie but i got the same error. I also check the coordinate and everything it's all right. The only difference that i found while I'm debugging the code it's this:
The object that are added correctly to the maps looks like this in the debugger:
Instead when i get the error, the object that I'm adding to the map looks like this on the simulator:
and when i print the content of: 0 i get this:
Printing description of *([0]->[0]):
(Photo_Photo_) [0] = {}
which it's look like a pointer to an empty entity.
do you have any idea of how can i solve this?
Thanks

Answer 1

After submitting the bug report Apple told me the solution for my problem. The problem was that i was updating the coordinate in a non KVO compliant way. I store the properties like you, with latitude and longitude. Try adding this on your Photo class.
- (void)willChangeValueForKey:(NSString *)key
{
if ([key isEqualToString:#"latitude"] || [key isEqualToString:#"longitude"]) { [self willChangeValueForKey:#"coordinate"]; }
[super willChangeValueForKey:key];
}
- (void)didChangeValueForKey:(NSString *)key
{
if ([key isEqualToString:#"latitude"] || [key isEqualToString:#"longitude"]) { [self didChangeValueForKey:#"coordinate"]; }
[super didChangeValueForKey:key];
}
Hope this helps.