CLLocationManager不会向didUpdateLocations方法发送位置

Question

I am working on an iOS 6.1 iPhone app with ARC enabled which will be using a CLLocationManager to track the devices position.

UPDATE

I have a DestinationViewController which implements the CLLocationManagerDelegate . It creates the CLLocationManager and does the setup. I have imported the CoreLocation framework to my project.

I have tried to debug a lot and can see that the CLLocationManager is created and no errors are present. But the problem is that the [CLLocationManager authorizationStatus] is kCLAuthorizationStatusNotDetermined both before [self.locationManager startUpdatingLocation]; and also after . So there is no prompt about asking permission to use location services for this app. Because of that this method is never fired.

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:  
(NSArray *)locations

I have also tried to search the web for hours to look for similar examples but with no luck. Code from DestinationViewController is posted below.

Interface

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

@interface DestinationViewController : UIViewController <CLLocationManagerDelegate>

Implementation

#import "DestinationViewController.h"

@interface DestinationViewController ()
@property (strong, nonatomic) CLLocationManager *locationManager;
@end


@implementation DestinationViewController

// Initializer
- (CLLocationManager *)locationManager
{
    if (!_locationManager) {
        _locationManager = [[CLLocationManager alloc] init];
    }
    return _locationManager;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    [self startLocation];
}


- (void)startLocation
{
    self.locationManager.delegate = self;
    self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
    self.locationManager.distanceFilter = 1;

    NSString *error;
    if (![CLLocationManager locationServicesEnabled]) {
        error = @"Error message";
    }

    CLAuthorizationStatus status = [CLLocationManager authorizationStatus];
    if (status == kCLAuthorizationStatusRestricted ||
        status == kCLAuthorizationStatusDenied ||) {
        error = @"Error message";
    }

    if (error) {
        NSLog(error);
    }
    else
    {

        status = [CLLocationManager authorizationStatus];

    self.locationManager.pausesLocationUpdatesAutomatically = NO;

        [self.locationManager startUpdatingLocation];

        status = [CLLocationManager authorizationStatus];

        NSLog(@"CLLocationManager is %@", self.locationManager);
        NSLog(@"Location is %@", self.locationManager.location);

        [self updateUI];
    }
}


- (void)locationManager:(CLLocationManager *)manager
     didUpdateLocations:(NSArray *)locations
{
    CLLocation *recentLocation = [locations lastObject];
    NSLog(@"Found location");
}

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

- (void)locationManager:(CLLocationManager *)manager didChangeAuthorizationStatus:(CLAuthorizationStatus)status
{
    NSLog(@"Change in authorization status");
}

Answer 1

Your code should work.

Make sure your application is authorized to use location services.

You can use following method to check authorization status in code

 + (CLAuthorizationStatus)authorizationStatus

Edit

kCLAuthorizationStatusNotDetermined is most likely caused by location services being disabled. You should check location services status first. Code should be like this

if([CLLocationManager locationServicesEnabled]) {
    // Location Services Are Enabled
    switch([CLLocationManager authorizationStatus]) {
        case kCLAuthorizationStatusNotDetermined:
            // User has not yet made a choice with regards to this application
            break;
        case kCLAuthorizationStatusRestricted:
            // This application is not authorized to use location services.  Due
            // to active restrictions on location services, the user cannot change
            // this status, and may not have personally denied authorization
            break;
        case kCLAuthorizationStatusDenied:
            // User has explicitly denied authorization for this application, or
            // location services are disabled in Settings
            break;
        case kCLAuthorizationStatusAuthorized:
            // User has authorized this application to use location services
            break;
    }
} else {
    // Location Services Disabled
}

Answer 2

I finally solved it! My delegate wasn't set properly. Instead of doing:

self.locationManager.delegate = self;

I changed it to:

[self.locationManager setDelegate:self];

And now my delegate methods get fired.

Thanks to those who helped!