Add annotation pin on touch using MapKit and UIGestureRecognizer - objective-c

Question

I have some problems with adding annotations when the user touch the map.
I'm using UIGestureRecognizer to detect the user's touch.
When a long press is detected, I'm calling this function :
- (void)handleLongPressGesture:(UIGestureRecognizer*)gestureRecognizer{
if (gestureRecognizer.state == UIGestureRecognizerStateEnded) return;
NSLog(#"long press");
CGPoint touchPoint = [gestureRecognizer locationInView:mapView];
CLLocationCoordinate2D touchMapCoordinate =
[mapView convertPoint:touchPoint toCoordinateFromView:mapView];
RdvAnnotation *rdvAnnotation = [[RdvAnnotation alloc] init];
[rdvAnnotation initWithCoordinate:touchMapCoordinate];
[mapView removeAnnotations:mapView.annotations];
[mapView addAnnotation:rdvAnnotation];
[rdvAnnotation release]; }
I cans see the NSLog in the console and the rdvAnnotation is initialized with the good coordinate.
I don't understand why I can't see my annotation on the map.
Here's my - (MKAnnotationView *)mapView:(MKMapView *)theMapView viewForAnnotation:(id <MKAnnotation>)annotation method:
- (MKAnnotationView *)mapView:(MKMapView *)theMapView viewForAnnotation:(id <MKAnnotation>)annotation{
if ([annotation isKindOfClass:[MKUserLocation class]])
return nil;
if ([annotation isKindOfClass:[RdvAnnotation class]])
{
static NSString* RdvAnnotationIdentifier = #"rdvAnnotationIdentifier";
MKPinAnnotationView* pinView = (MKPinAnnotationView *)
[mapView dequeueReusableAnnotationViewWithIdentifier:RdvAnnotationIdentifier];
if (!pinView)
{
MKPinAnnotationView* customPinView = [[[MKPinAnnotationView alloc]
initWithAnnotation:annotation reuseIdentifier:RdvAnnotationIdentifier] autorelease];
customPinView.pinColor = MKPinAnnotationColorPurple;
customPinView.animatesDrop = YES;
customPinView.canShowCallout = YES;
return customPinView;
}
else
{
pinView.annotation = annotation;
}
return pinView;
}
return nil;}
My viewDidLoad method:
- (void)viewDidLoad {
[super viewDidLoad];
mapView = [[MKMapView alloc] initWithFrame:self.view.frame];
[mapView setShowsUserLocation:TRUE];
[mapView setMapType:MKMapTypeStandard];
[mapView setDelegate:self];
CLLocationManager *locationManager=[[CLLocationManager alloc] init];
[locationManager setDelegate:self];
[locationManager setDesiredAccuracy:kCLLocationAccuracyNearestTenMeters];
[locationManager startUpdatingLocation];
self.navigationItem.title = #"Rendez-vous" ;
}

Answer 1

I just noticed something that seems weird :
RdvAnnotation *rdvAnnotation = [[RdvAnnotation alloc] init];
[rdvAnnotation initWithCoordinate:touchMapCoordinate];
You're calling init twice on the annotation object. You should just do it this way :
RdvAnnotation *rdvAnnotation = [[RdvAnnotation alloc] initWithCoordinate:touchMapCoordinate]];
EDIT :
If you have code in your init method that you don't want to lose, keep the init and change the value of the coordinate property :
RdvAnnotation *rdvAnnotation = [[RdvAnnotation alloc] init];
rdvAnnotation.coordinate = touchMapCoordinate;

Answer 2

In viewDidLoad you are creating a new map view object.
First, this new map view object is not being added as a subview to self.view so it exists in memory but is invisible.
Second, you probably already have a map view object placed in the view in Interface Builder so you don't need to create a new one.
So what is probably happening is that when you add the annotation, it is being added to the map view object in memory but not the one that is visible (the one that was created in IB).
Instead of creating a new map view in viewDidLoad, connect the mapView IBOutlet to the map view in Interface Builder.