Question

I am getting an error when my application becomes active again. it returns from background.

I am guessing its my gyro but haven’t found a solution.

My error:

-[WebDataSource onGeomagneticModel:]: unrecognized selector sent to instance 0x37c430
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[WebDataSource onGeomagneticModel:]: unrecognized selector sent to instance 0x37c430'

my applicationDidEnterBackground:

- (void)applicationDidEnterBackground:(UIApplication *)application{
    NSLog(@"Application moving to background");
    LocationManagerDelegate *locationController = [[LocationManagerDelegate alloc] init];
    [locationController.locationManager stopUpdatingHeading];
    [locationController stopDeviceMotion];


}

Answer 1

It looks like you create another LocationManagerDelegate instance.
So.. the “old” instance you did NOT turn of.

You should add in you .h file

@property (nonatomic, retain) LocationManagerDelegate *locationController;

Then add above the @implementaion in the .m file

@synthesize locationController=locationController_;

There where you crate your LocationManagerDelegate you need to change it somehow to (you did not post that part of code):

self.locationController = [[[LocationManagerDelegate alloc] init] autorelease];

Then change your code to:

- (void)applicationDidEnterBackground:(UIApplication *)application{
    NSLog(@"Application moving to background");
    [self.locationController.locationManager stopUpdatingHeading];
    [self.locationController stopDeviceMotion];
}