I am trying to send a location update with the new location as a notification object. When I do, I receive a "EXC_BAD_ACCESS" error when I try to access the data from the notification. If I execute "po location" I see the data, but it is unclear to me why I cannot acquire it. When setting the observer, I also tried assigning the object parameter to a member variable, but then locationUpdate is never called.
Here's my code (note that ARC is enabled):
// LocationController.h
@protocol LocationDelegateProtocol
@required
- (void)locationUpdate:(CLLocation *)location;
@end
@interface LocationController : NSObject <CLLocationManagerDelegate> {
CLLocationManager *locationManager;
id delegate;
}
@property(nonatomic, retain) CLLocationManager *locationManager;
@property(nonatomic, strong) id delegate;
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation;
+ (LocationController *)sharedInstance; // this class is a singleton
@end
// LocationController.m
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
[Notification locationChanged:newLocation];
}
// Notification.h
@interface Notification : NSObject
+ (void)locationChanged:(CLLocation *)newLocation;
@end
extern NSString *const kLocationChanged;
// Notification.m
NSString *const kLocationChanged = @"NewLocation";
[[NSNotificationCenter defaultCenter] postNotificationName:kLocationChanged object:newLocation];
// ViewController.h
@interface ViewController : UIViewController <UITableViewDelegate, UITableViewDataSource, LocationDelegateProtocol> {
...
}
...
- (void)locationUpdate:(CLLocation *)location;
@end
// ViewController.m
- (void)setupNotifications {
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(locationUpdate:) name:kLocationChanged object:nil];
// I've tried setting object to a member var "CLLocation *objectFromNotification", but then locationUpdate() is never called.
}
- (void)locationUpdate:(NSNotification *)notification {
CLLocation *location = (CLLocation *) [notification object];
// program receives signal "EXC_BAD_ACCESS" when executing NSLog below. I can see data inside location when I execute "po location".
NSLog(@"latitude = %@, longitude = %@",location.coordinate.latitude, location.coordinate.longitude);
Change the format specifier in your NSLog from %@ to %f. You are trying to access float value as object!