buzzkip buzzkip - 11 days ago 5
Objective-C Question

MKMapView zoom to users location on viewDidLoad?

I'm trying to zoom a map into the user's current location once the view loads, but I'm getting the error "** * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Invalid Region '" when the view loads. Please can someone help?

Cheers!

- (void)viewDidLoad
{
[super viewDidLoad];

MKCoordinateRegion mapRegion;
mapRegion.center.latitude = map.userLocation.coordinate.latitude;
mapRegion.center.longitude = map.userLocation.coordinate.longitude;
mapRegion.span.latitudeDelta = 0.2;
mapRegion.span.longitudeDelta = 0.2;
[map setRegion:mapRegion animated: YES];
}

Answer

did you set showsUserLocation = YES? MKMapView won't update the location if it is set to NO. So make sure of that.

It is very likely that the MKMapView object doesn't have the user location yet. To do right, you should adopt MKMapViewDelegate protocol and implement mapView:didUpdateUserLocation:

map.delegate = self;

...
-(void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation 
{
    MKCoordinateRegion mapRegion;   
    mapRegion.center = mapView.userLocation.coordinate;
    mapRegion.span.latitudeDelta = 0.2;
    mapRegion.span.longitudeDelta = 0.2;

    [mapView setRegion:mapRegion animated: YES];
}
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