Pins have disappeared when using MKAnnotationView delegate

Question

My MKAnnotationView delegate method is been called as I can see my NSLog output. However the pins are not appearing on the map. Is there something I'm missing here?

MapViewController.h

#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>

@interface MapViewController : UIViewController <MKMapViewDelegate>
@property (weak, nonatomic) IBOutlet MKMapView *nearbyMapView;
@end

MapViewController.m

#import "MapViewController.h"
#import "AppDelegate.h"

@interface MapViewController ()

@end

@implementation MapViewController
AppDelegate *appDelegate;

- (void)viewDidLoad
{
    [super viewDidLoad];    
    appDelegate=[[UIApplication sharedApplication] delegate];
    CLLocationCoordinate2D center = CLLocationCoordinate2DMake(54.995184, -1.566699);
    MKCoordinateSpan span = MKCoordinateSpanMake(0.5, 0.5);
    MKCoordinateRegion regionToDisplay = MKCoordinateRegionMake(center, span);
    [self.nearbyMapView setRegion: regionToDisplay];

    for (int i = 0; i < [[appDelegate offersFeeds] count]; i++) {
        CLGeocoder *geocoder = [[CLGeocoder alloc] init];
        NSString *plotAddress = [[[appDelegate offersFeeds] objectAtIndex:i] valueForKey:@"addressline"];
        NSString *plotTitle = [[[appDelegate offersFeeds] objectAtIndex:i] valueForKey:@"title"];

        [geocoder geocodeAddressString:plotAddress completionHandler:^(NSArray *placemarks, NSError *error) {
            if (placemarks && placemarks.count > 0)
            {
                CLPlacemark *topResult = [placemarks objectAtIndex:0];
                MKPlacemark *placemark = [[MKPlacemark alloc]initWithPlacemark:topResult];

                MKPointAnnotation *pa = [[MKPointAnnotation alloc] init];
                pa.coordinate = placemark.location.coordinate;
                pa.title = plotTitle;

                [self.nearbyMapView addAnnotation:pa];
            }
        }];
    }
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation {
    MKAnnotationView *pinView = nil;

    static NSString *defaultPinID = @"identifier";
    pinView = (MKAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:defaultPinID];
    if ( pinView == nil ) {
        NSLog(@"Inside IF");
        pinView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:defaultPinID];
        pinView.enabled = YES;
        pinView.canShowCallout = YES;
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];    
        //Accessoryview for the annotation view in ios.
        pinView.rightCalloutAccessoryView = btn;
    }
    else {
        pinView.annotation = annotation;
    }
    pinView.annotation = annotation;
    return pinView;
}

@end

Answer 1

In viewForAnnotation, the code is creating an MKAnnotationView but not setting an image for it. There is no default image on an MKAnnotationView so the annotations are invisible.

When you don't implement the delegate at all, the map view creates MKPinAnnotationViews for you with a red pin color. MKPinAnnotationView is a convenient subclass of MKAnnotationView which supplies a pin image (in one of three colors).

When you implement the delegate, it's up to you to create the right view and set the properties as needed.

Either create an MKPinAnnotationView instead (which provides a default pin image) or set the image property on the plain MKAnnotationView.

To use MKPinAnnotationView:

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id             <MKAnnotation>)annotation
{
    MKPinAnnotationView *pinView = nil;

    static NSString *defaultPinID = @"identifier";
    pinView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:defaultPinID];
    if ( pinView == nil )
    {
        NSLog(@"Inside IF");
        pinView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:defaultPinID];

        pinView.pinColor = MKPinAnnotationColorRed;  //or Green or Purple

        pinView.enabled = YES;
        pinView.canShowCallout = YES;

        UIButton *btn = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];

        //Accessoryview for the annotation view in ios.
        pinView.rightCalloutAccessoryView = btn;
    }
    else
    {
        pinView.annotation = annotation;
    }

    return pinView;
}

or to use MKAnnotationView and your own image:

//same code as the current but add this line
//after the initWithAnnotation:
pinView.image = [UIImage imageNamed:@"SomeImage.png"];