Problem in Mapkit

I am using following code to show location of the objects.

 - (void)viewDidLoad {
[super viewDidLoad];
[self selectData];


locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
locationManager.distanceFilter = kCLDistanceFilterNone;
[locationManager startUpdatingLocation];

CLLocation *location = [locationManager location];

// Configure the new event with information from the location
CLLocationCoordinate2D coordinate1 = [location coordinate];

//NSString *latitude = [NSString stringWithFormat:@"%f", coordinate1.latitude];
//NSString *longitude = [NSString stringWithFormat:@"%f", coordinate1.longitude];


mapView.showsUserLocation=YES;
mapView.delegate=self;

//MKMapView *mapView = (MKMapView*)self.view;

CLLocationCoordinate2D coordinate;

coordinate.latitude = coordinate1.latitude;

coordinate.longitude =coordinate1.longitude;

//mapView.region = ; 
[mapView setRegion:MKCoordinateRegionMakeWithDistance(coordinate, 2000, 2000)];
NSUInteger count = 1;
[self setTitle:[NSString stringWithFormat:@"%i Memories",[memoryArray count]]];
for(int i = 0; i < [memoryArray count]; i++) {
    MemoryData *m=[memoryArray objectAtIndex:i];

    //CGFloat latDelta = rand()*.035/RAND_MAX -.02;

    //CGFloat longDelta = rand()*.03/RAND_MAX -.015;
    coordinate.latitude=[m.lat floatValue];
    coordinate.longitude=[m.lon floatValue];

    CLLocationCoordinate2D newCoord = {coordinate.latitude,    coordinate.longitude};

    MapDemoAnnotation* annotation = [[MapDemoAnnotation alloc]initWithCoordinate:newCoord andID:count++];
    [annotation setMemoryData:m];
    [annotation setTag:i];

    [mapView addAnnotation:annotation];

    [annotation release];

} 

}

   - (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation {

MKPinAnnotationView *pinView = (MKPinAnnotationView*)[mapView dequeueReusableAnnotationViewWithIdentifier:@"Pin"];

if(pinView == nil) {

    p开发者_运维技巧inView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"Pin"];

    pinView.pinColor = MKPinAnnotationColorRed;
    int t=((MapDemoAnnotation*)annotation).tag ;
    NSLog(@"Tag is %i ",t);


    pinView.animatesDrop = YES;
    pinView.canShowCallout = YES;
    UIImageView *pinImageView = [[UIImageView alloc] initWithFrame:CGRectMake(-5, 0, 34, 34)];

    UIImage *pinImage = [[UIImage alloc] initWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"photo" ofType:@"JPG"]];

    pinImageView.image = pinImage;

    //[pinImage release]; 

    //[pinView addSubview:pinImageView];

    //[pinImageView release];
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];

    btn.tag = t;

    pinView.rightCalloutAccessoryView = btn;


    //pinView.rightCalloutAccessoryView=pinImageView;

} else {

    pinView.annotation = annotation;

}

return pinView;

}

  -(void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view calloutAccessoryControlTapped:(UIControl *)control {

ViewItemList *list=[[ViewItemList alloc]init];
MemoryData *m=[memoryArray objectAtIndex:control.tag];

[list setMemoryData:m];
[self.navigationController pushViewController:list animated:YES];

}

If I am testing on ipod it works fine. but it i test on iphone or on simulator it shows following error .

 Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[MKUserLocation tag]: unrecognized selector sent to instance 0xac20da0'

Please help

It seems the problem is that your custom class MapDemoAnnotation is not a subclass of UIView which implements the tag property. According to your error, it thinks it is a subclass of MKUserLocation.

If you classes are OK in this respect, most likely your cast is not working. Maybe you are over-using the parentheses? Try writing the line like this:

MapDemoAnnotation *myDemo = (MapDemoAnnotation *) annotation;
int t = myDemo.tag;