Why is my CLLocationmanager delegate not getting called?

Question

I'm not getting any location callbacks on either sim or device. I've got this code being called:

- (void)startLocationCallbacks: (NSObject*) ignore
{
  locationManager.delegate = self;
  locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
  locationManager.distanceFilter = MINIMUM_METERS;

  [locationManager startUpdatingLocation];
  NSLog(@"[DEBUG] [locationManager startUpdatingLocation] (%@, %@)", locationManager, locationManager.delegate);
}

and log statements at the top of both

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error

and

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation

but neither log statement ever gets called. Location Notifications are enabled for my app (as shown in Settings, plus I said "allow.")

What are some possible reasons that I'm not getting location updates?

Config/other info:

• I have allocated locationManager, and saved it in a retain property.
• I have called startUpdatingLocation
• I'm using 4.1 SDK
• Problem is on both Sim & iPod-touch (2nd Gen) & iPhone-3, all running 4.1
• Location notifications are allowed in my app (both as indicated in Settings and because I clicked "allow" in the alert.)
• I've used CLLocationManager successfully before (in many shipping apps!) This is a real hair-puller for me.

Thanks!

Answer 1

Whew! Ok, I found it.

It turns out that one of the ways to make a CLLocationManager not fire off location callbacks is to do all the set-up in not-the-main-thread. When I moved my setup routine to a performSelectorOnMainThread, all worked exactly as expected.

What a nightmare!

Hope this answer helps others...

Edit/clarification:

Originally, I had something like this:

- (BOOL) appDidFinishLaunchingWithOptions: (NSDictionary*) options
{
     // ...[app setup, snip]
    [NSThread detachNewThreadSelector: @selector(postLaunchSetupThread) toTarget: self withObject: nil];
}

- (void)postLaunchSetupThread
{
    NSAutoreleasePool *pool = [NSAutoreleasePool new];
    // ...[other setup, snip]
    [self setupLocationManager];
    [pool release];
}

- (void)setupLocationManager
{
     self.myLocationManager = [[[CLLocationManager alloc] init] autorelease];
     [myLocationManager startLocationUpdates];
}

But calling setupLocationManager in a thread prevented the callbacks. So my fix was to move the line

[self setupLocationManager];

out of the thread and back into appDidFinishLaunchingWithOptions

Answer 2

Actually you can run it from another thread as well. From Apple documentation:

Configuration of your location manager object must always occur on a thread with an active run loop, such as your application’s main thread.

Just make sure your run loop is running on that thread, and the CLLocationManager events are dispatched. More about run loop: https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Multithreading/RunLoopManagement/RunLoopManagement.html

Answer 3

For iOS 8

1) I placed these lines right after I init'd the location manager.

if([self.locationManager respondsToSelector:@selector(requestAlwaysAuthorization)]) {
    [self.locationManager requestAlwaysAuthorization];
}

2) I added NSLocationAlwaysUsageDescription to the plist and set it to a string and added a message. 3) In my target, I clicked on Capabilities tab, and then turned on Background Modes and checked "Location Updates" and "Uses Bluetooth LE accessories"

This worked for me

Answer 4

// check out this //...CLLocationManager does n't call delegate method properly

//...after lot of R&D I'm using a watchdog method it calls "

https://stackoverflow.com/questions/7156920/didupdatetolocation-doesnt-gets-called-immediately/14605889#14605889

Answer 5

In my case it was because of my device was unable to determine location - while staying indoors GPS signal was unavailable and wi-fi was also disconnected so location manager just wasn't able to receive any location data and delegate was never called.

Once I've connected wi-fi it worked (I guess moving outdoors should also do the trick in that case, but sometimes it is not very convenient way :) )