objective-c getting location and notifiy if updated. observer? how?

Question

I use the locationmanger to get my current location on the iPhone.

#pragma mark - Location handling
-(void)doLocation {
    self.locationManager = [[CLLocationManager alloc] init];
    [...]
    SingletonClass *sharedSingleton = [SingletonClass sharedInstance];
    sharedSingleton.coordinate = [location coordinate];
}

- (void)locationManager:(CLLocationManager *)manager
    didUpdateToLocation:(CLLocation *)newLocation
           fromLocation:(CLLocation *)oldLocation
{
    [...]
    SingletonClass *sharedSingleton = [SingletonClass sharedInstance];
    [sharedSingleton setCoordinate:CLLocationCoordinate2DMake(currentLat, currentLng)];

    NSLog(@"debug: self.currentLoc: %@", self.currentLoc);

}

this works fine, I get the location coordinates with some delay and can access them via the sharedSingleton. When I have the coordinates, I have to trigger another function which needs the coordinates as parameter.

And here my issue starts...

How do I now, when the coordinates are retrieved and I can call the other function which needs the coordinates as input parameters. Is there a kind of observer that I could use? If, how do I implement this?

I just need something that tells me: hey dude, the coordinates are available for use, so that I can trigger the next function..

score 1 · Accepted Answer · answered Jul 02 '13 at 20:57

You can use the NSNotificationCenter or a delegate. Delegate pattern in objective C is really common. For that you will need to implement a protocol in your .h file, something like this:

@protocol MyLocationManagerDelegate <NSObject>
- (void) locationManager:(MyLocationManager *)manager didFindLocation:(CCLocation*) location
@end

//still in your .h file add a delegate that implements this protocol
@property (nonatomic, assign) id<MyLocationManagerDelegate> delegate

Then in the other class that must take the action when coordinates are found, indicates that it implements the MyLocationManagerDelegate protocol, and implement the - (void) locationManager:(MyLocationManager *)manager didFindLocation:(CCLocation*) location method.

After allocating your location manager set your other class as the delegate. And in your didUpdateToLocation method simply call [self.delegate locationManager:self didFindLocation:self.currentLoc]

had a look at delegation pattern http://enroyed.com/ios/delegation-pattern-in-objective-c-and-writing-custom-delegates/. Seems to me the way to go. Have to test ist now with your suggested solution — jerik, Jul 03 '13 at 09:31

score 0 · Answer 2 · edited May 23 '17 at 12:11

0

One way to achieve this functionality is NSNotificationCenter.

This post will show you how to set up a notification through NSNotificationCenter.

Send And Recieve Messages Through NSNotificationCenter In Objective-c

edited May 23 '17 at 12:11

Community

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answered Jul 02 '13 at 20:53

Eric

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objective-c getting location and notifiy if updated. observer? how?

2 Answers2