NSArrayM was mutated while being enumerated - iphone

Question

App crashes with error:
*** Terminating app due to uncaught exception 'NSGenericException', reason: '*** Collection <__NSArrayM: 0x21481c10> was mutated while being enumerated.'
This happen only if I move over mapview when my annotations is loading. If I doesn't touch map, no error occurred.
- (void) startloading
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),
^{
[self loadPList];
});
}
my code is:
- (void) loadPList
{
#autoreleasepool {
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *path = [[documentPaths lastObject] stringByAppendingPathComponent:#"test.plist"];
NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:path];
NSMutableArray *annotations = [[NSMutableArray alloc]init];
NSMutableArray * annotationsToRemove = [ mapView.annotations mutableCopy ] ;
[ annotationsToRemove removeObject:mapView.userLocation ] ;
[ mapView removeAnnotations:annotationsToRemove ] ;
if ([[NSUserDefaults standardUserDefaults] boolForKey:#"blackKey"])
{
NSArray *ann = [dict objectForKey:#"Black"];
for(int i = 0; i < [ann count]; i++) {
NSString *coordinates = [[ann objectAtIndex:i] objectForKey:#"Coordinates"];
double realLatitude = [[[coordinates componentsSeparatedByString:#","] objectAtIndex:1] doubleValue];
double realLongitude = [[[coordinates componentsSeparatedByString:#","] objectAtIndex:0] doubleValue];
MyAnnotation *myAnnotation = [[MyAnnotation alloc] init];
CLLocationCoordinate2D theCoordinate;
theCoordinate.latitude = realLatitude;
theCoordinate.longitude = realLongitude;
myAnnotation.coordinate=CLLocationCoordinate2DMake(realLatitude,realLongitude);
myAnnotation.title = [[ann objectAtIndex:i] objectForKey:#"Name"];
myAnnotation.subtitle = [[ann objectAtIndex:i] objectForKey:#"Address"];
myAnnotation.icon = [[ann objectAtIndex:0] objectForKey:#"Icon"];
[mapView addAnnotation:myAnnotation]; // SIGNAL SIGABRT
[annotations addObject:myAnnotation];
}
}
if ([[NSUserDefaults standardUserDefaults] boolForKey:#"blueyellowKey"])
{
NSArray *ann = [dict objectForKey:#"BlueYellow"];
for(int i = 0; i < [ann count]; i++) {
NSString *coordinates = [[ann objectAtIndex:i] objectForKey:#"Coordinates"];
double realLatitude = [[[coordinates componentsSeparatedByString:#","] objectAtIndex:1] doubleValue];
double realLongitude = [[[coordinates componentsSeparatedByString:#","] objectAtIndex:0] doubleValue];
MyAnnotation *myAnnotation = [[MyAnnotation alloc] init];
CLLocationCoordinate2D theCoordinate;
theCoordinate.latitude = realLatitude;
theCoordinate.longitude = realLongitude;
myAnnotation.coordinate=CLLocationCoordinate2DMake(realLatitude,realLongitude);
myAnnotation.title = [[ann objectAtIndex:i] objectForKey:#"Name"];
myAnnotation.subtitle = [[ann objectAtIndex:i] objectForKey:#"Address"];
myAnnotation.icon = [[ann objectAtIndex:0] objectForKey:#"Icon"];
[mapView addAnnotation:myAnnotation];
[annotations addObject:myAnnotation];
}
}
}
}

Answer 1

I think you should change your loadPlist method to this, and then just call [self loadPlist] to invoke it:
- (void) loadPList
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *path = [[documentPaths lastObject] stringByAppendingPathComponent:#"test.plist"];
NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:path];
//ALL THIS CODE FROM HERE ON OUT IS NOT THREAD SAFE! YOU ARE ACCESSING THE UI AND MUST PERFORM IT ON THE MAIN THREAD!
dispatch_async(dispatch_get_main_queue(), ^{
NSMutableArray *annotations = [[NSMutableArray alloc]init];
NSMutableArray * annotationsToRemove = [ mapView.annotations mutableCopy ] ;
[ annotationsToRemove removeObject:mapView.userLocation ] ;
[ mapView removeAnnotations:annotationsToRemove ] ;
if ([[NSUserDefaults standardUserDefaults] boolForKey:#"blackKey"])
{
NSArray *ann = [dict objectForKey:#"Black"];
for(int i = 0; i < [ann count]; i++) {
NSString *coordinates = [[ann objectAtIndex:i] objectForKey:#"Coordinates"];
double realLatitude = [[[coordinates componentsSeparatedByString:#","] objectAtIndex:1] doubleValue];
double realLongitude = [[[coordinates componentsSeparatedByString:#","] objectAtIndex:0] doubleValue];
MyAnnotation *myAnnotation = [[MyAnnotation alloc] init];
CLLocationCoordinate2D theCoordinate;
theCoordinate.latitude = realLatitude;
theCoordinate.longitude = realLongitude;
myAnnotation.coordinate=CLLocationCoordinate2DMake(realLatitude,realLongitude);
myAnnotation.title = [[ann objectAtIndex:i] objectForKey:#"Name"];
myAnnotation.subtitle = [[ann objectAtIndex:i] objectForKey:#"Address"];
myAnnotation.icon = [[ann objectAtIndex:0] objectForKey:#"Icon"];
[mapView addAnnotation:myAnnotation]; // SIGNAL SIGABRT
[annotations addObject:myAnnotation];
}
}
if ([[NSUserDefaults standardUserDefaults] boolForKey:#"blueyellowKey"])
{
NSArray *ann = [dict objectForKey:#"BlueYellow"];
for(int i = 0; i < [ann count]; i++)
{
NSString *coordinates = [[ann objectAtIndex:i] objectForKey:#"Coordinates"];
double realLatitude = [[[coordinates componentsSeparatedByString:#","] objectAtIndex:1] doubleValue];
double realLongitude = [[[coordinates componentsSeparatedByString:#","] objectAtIndex:0] doubleValue];
MyAnnotation *myAnnotation = [[MyAnnotation alloc] init];
CLLocationCoordinate2D theCoordinate;
theCoordinate.latitude = realLatitude;
theCoordinate.longitude = realLongitude;
myAnnotation.coordinate=CLLocationCoordinate2DMake(realLatitude,realLongitude);
myAnnotation.title = [[ann objectAtIndex:i] objectForKey:#"Name"];
myAnnotation.subtitle = [[ann objectAtIndex:i] objectForKey:#"Address"];
myAnnotation.icon = [[ann objectAtIndex:0] objectForKey:#"Icon"];
[mapView addAnnotation:myAnnotation];
[annotations addObject:myAnnotation];
}
}
}
});
}
This performs the IO work of reading in the annotations in the background, and then passes off the UI work back to the main thread. Hope this helps!