MapKit Annotations do not appear on the map

Question

I'm having trouble displaying MKAnnotationViews on a map in MapKit. I use iOS 7 and now I look at forums and the Internet many times, trying different samples and settings.

Below I have the easiest setup (I think) for it to work. The application contains one ViewController with a toolbar with a button at the top, and the rest is a MapView. The button starts the zoomToUser: (UIBarButtonItem *) method of the sender. Right-clicking and checking my points and delegates seem correct. I have NSLog instructions that run to display some debugging information.

First VC:

#import "ViewController.h"
#import "Data.h"

@interface ViewController () <MKMapViewDelegate>
@property (weak, nonatomic) IBOutlet MKMapView *mapView;
- (IBAction)zoomToUser:(UIBarButtonItem *)sender;
@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.mapView.showsUserLocation = YES;
    Data *ann = [[Data alloc] init];
    [self.mapView addAnnotation:ann];
}

-(void)viewDidAppear:(BOOL)animated
{
        [super viewDidAppear:animated];
        [self zoomToUser:nil];
    }

-(IBAction)zoomToUser:(UIBarButtonItem *)sender
{
    MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(self.mapView.userLocation.coordinate, 2000, 2000);
    NSLog(@"region: %f x %f",self.mapView.userLocation.coordinate.latitude,self.mapView.userLocation.coordinate.longitude);
    [self.mapView setRegion:region animated:YES ];
    NSArray *arr = self.mapView.annotations;
    for(int i = 0, max = arr.count; i < max; i++)
    {
        id<MKAnnotation> annotation = arr[i];
        NSLog(@"%d of %d: %@ (%@)",i+1,max,annotation.title, [annotation class]);
    }
}

- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation
{
    NSString *reuseId = @"Test";
    if([annotation isKindOfClass:[MKUserLocation class]])
    {
        return nil;
    }
    else if( [annotation isKindOfClass:[Data class]])
    {
        MKAnnotationView *annov = [mapView    dequeueReusableAnnotationViewWithIdentifier:reuseId];
        if(!annov)
        {
            annov = [[MKAnnotationView alloc]initWithAnnotation:annotation
                                                reuseIdentifier:reuseId];
        }
        else
        {
            annov.annotation = annotation;
        }
        annov.canShowCallout = YES;
        NSLog(@"Title: %@",annotation.title);
        return annov;
    }
    else
    {
        return nil;
    }
}
@end

And the class Data:

#import "Data.h"

@implementation Data

-(NSString *)title
{
    return @"The title";
}

-(NSString *)subtitle
{
    return @"A subtitle";
}

-(CLLocationCoordinate2D)coordinate
{
    CLLocationCoordinate2D coordinate;
    coordinate.latitude = 60.123456;
    coordinate.longitude = 10.123456;
    return coordinate;
}

@end

Data.h:

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

@interface Data : NSObject <MKAnnotation>

@end

And ViewController.h:

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

@interface ViewController : UIViewController

@end

, viewForAnnotation , , , , .

BarButton zoomToUser: - , , MKUserLocation , .

MapView , , , , ?

Answer 1

viewForAnnotation MKAnnotationView Data.

MKAnnotationView .
image nil, .
, , , .

:

• image MKAnnotationView:

  annov.image = [UIImage imageNamed:@"something"];
  

• , MKPinAnnotationView , MKAnnotationView, -:

  MKPinAnnotationView *annov = (MKPinAnnotationView *)[mapView dequeue...
  if(!annov)
  {
      annov = [[MKPinAnnotationView alloc]initWithAnnotation:annotation
                                          reuseIdentifier:reuseId];
      annov.pinColor = MKPinAnnotationColorRed;  //or Green or Purple
  }
  else
  ...
  

Unrelated:
Data, , title, subtitle coordinate, MKPointAnnotation, :

MKPointAnnotation *ann = [[MKPointAnnotation alloc] init];
ann.title = @"The title";
ann.subtitle = @"A subtitle";
ann.coordinate = CLLocationCoordinate2DMake (60.123456, 10.123456);
[self.mapView addAnnotation:ann];