CLLocationManager never calls delegate methods [duplicate]

Question

Hi I'm playing around with locations on iPhone and right from the start I ran into problems. I've localized my problem and determined it's CLLocationManager that's bugging me.

So I developed very simple application. I just have a view controller with a CLLocationManager in it. On view did load I initialize CLLocationManager and start updating. I've also implemented two methods didFailWithError and didUpdateToLocation.

I've read a lot of questions and what i have learned so fare is this. You have to retain CLLocationManager during initialization. Also it's wise to set CLLocationManagers delegate to nil during unloading of a view (something to do with messages passing to CLLocationManager because framework retains it and it's never properly release)

All in all I just cant find a decent explanation on what to do and how to make it work.

Here's my code so if anybody could figure it out I would appreciate it. viewControllers header file

#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>

@interface CoreLocationViewController : UIViewController <CLLocationManagerDelegate>
{
    CLLocationManager *locManager;
}

@property (nonatomic, retain) CLLocationManager *locManager;

@end

viewController .m file

#import "CoreLocationViewController.h"


@implementation CoreLocationViewController
@synthesize locManager;

- (void)viewDidLoad 
{
    [super viewDidLoad];

    self.locManager = [[CLLocationManager alloc] init];
    locManager.delegate = self;
    [self.locManager startUpdatingLocation];

    self.view.backgroundColor = [UIColor grayColor];
}

#pragma mark -
#pragma mark Location Delegate

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
        NSLog(@"in fail with error");
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
    NSLog(@"in update to location");
}


#pragma mark -
#pragma mark Memory Management

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
}

- (void)viewDidUnload 
{
self.locManager.delegate = nil;
    [super viewDidUnload];
}


- (void)dealloc 
{
    [locManager release];
        [super dealloc];
}


@end

BTW: I'm using iOS 4.2. I'm pointing this out because I read that Apple has changed location delegates in iOS 4

Answer 1

In my case, the delegate never gets called because of threading problem

• the thread that operates LocationManager must have an NSRunLoop set up
• if you use main thread, you already have a runloop, now you just need to instantiate the manager and use it on main thread

Read this to know more about CLLocationManagerDelegate