Pin not showing on Mapkit - obj-c - ios

Question

I'm a newbie to ios dev. I tried to add pin annotations on map using mapkit. However, after tried the most basic methods, it still didn't show up, either that's a simple pin, or a custom annotationview. There is no error message, it's just the pin won't show up in the map.
Here's my code:
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.mapView.delegate = self;
NSLog(#"Custom Annotations start.");
// Custom Annotations.
CLLocationCoordinate2D bryanParkCoordinates = CLLocationCoordinate2DMake(37.785834, -122.406417);
MyCustomAnnotation *bryanParkAnnotation = [[MyCustomAnnotation alloc]initWithTitle:#"Bryant Park" Location:bryanParkCoordinates];
[self.mapView addAnnotation:bryanParkAnnotation];
// Simple pin.
MKPointAnnotation *annotation = [[MKPointAnnotation alloc] init];
[annotation setCoordinate:bryanParkCoordinates];
[annotation setTitle:#"Title"];
[self.mapView addAnnotation:annotation];
// Another try.
CLLocationCoordinate2D coord = CLLocationCoordinate2DMake(37.330713, -121.894348);
MKCoordinateSpan span = MKCoordinateSpanMake(0.1, 0.1);
MKCoordinateRegion region = {coord, span};
MKPointAnnotation *newannotation = [[MKPointAnnotation alloc] init];
[newannotation setCoordinate:coord];
[self.mapView setRegion:region];
[self.mapView addAnnotation:annotation];
// On your location.
MKPointAnnotation *point = [[MKPointAnnotation alloc] init];
point.coordinate = bryanParkCoordinates;
point.title = #"Where am I?";
point.subtitle = #"I'm here!!!";
[self.mapView addAnnotation:point];
}
-(MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation
{
if([annotation isKindOfClass:[MyCustomAnnotation class]])
{
MyCustomAnnotation *myLocation = (MyCustomAnnotation *)annotation;
MKAnnotationView *annotationView = [mapView dequeueReusableAnnotationViewWithIdentifier:#"MyCustomAnnotation"];
if(annotationView == nil)
annotationView = myLocation.annotationView;
else
annotationView.annotation = annotation;
return annotationView;
}
else{
MKPinAnnotationView *pinView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:#"DETAILPIN_ID"];
[pinView setAnimatesDrop:YES];
[pinView setCanShowCallout:NO];
return pinView;
}
}
If I just want a simple pin on map, just adding those lines
// Simple pin.
MKPointAnnotation *annotation = [[MKPointAnnotation alloc] init];
[annotation setCoordinate:bryanParkCoordinates];
[annotation setTitle:#"Title"];
[self.mapView addAnnotation:annotation];
should be enough? Is there other things that I could have missed? Like adding other delegate or something else other than adding those simple codes in 'viewDidLoad'? Thanks so much!

Answer 1

Managing Annotation Views
You should implement this delegate method and create a view for the annotation and return it.
basically when you add an annotation this delegates method will get called and you have to create the view for that annotation within this delegate method
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.mapView.delegate = self;
NSLog(#"Custom Annotations start.");
// Custom Annotations.
CLLocationCoordinate2D bryanParkCoordinates = CLLocationCoordinate2DMake(37.785834, -122.406417);
CLLocationCoordinate2D coord = CLLocationCoordinate2DMake(37.330713, -121.894348);
MKCoordinateSpan span = MKCoordinateSpanMake(0.1, 0.1);
MKCoordinateRegion region = {coord, span};
[self.mapView setRegion:region];
[self.mapView addAnnotation:annotation];
MKPointAnnotation *point = [[MKPointAnnotation alloc] init];
point.coordinate = bryanParkCoordinates;
point.title = #"Where am I?";
point.subtitle = #"I'm here!!!";
[self.mapView addAnnotation:point];
}

Answer 2

Try the following code:
- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation
{
if (annotation == mapView.userLocation) return nil;
static NSString* Identifier = #"PinAnnotationIdentifier";
MKPinAnnotationView* pinView;
pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:Identifier];
if (pinView == nil) {
pinView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation
reuseIdentifier:Identifier];
pinView.canShowCallout = YES;
return pinView;
}
pinView.annotation = annotation;
return pinView;
}
Don't forget to add <MKMapViewDelegate> to your #interface section.
#interface YourViewController () <MKMapViewDelegate>