Adding UIButtonTypeDetailDisclosure - Logic issue - iphone

Question

I have added a annotaion pin point to my application, and when the user clicks on the pin, the popup appears with the blue arrow on it (UIButtonTypeDetailDisclosure). Now what i want to do is, when the user clicks on it i need the view to redirect to another view with the more details about it.
for example: If its a Hospital that i click, and the popup will give its name and the UIButtonTypeDetailDisclosure button. When i click on the UIButtonTypeDetailDisclosure button, i should redirect to another view whcih gives more information about that hospital.
My code:
-(void)callingMap:(NSArray *)hospitalArray {
for(Hospital *hospital in hospitalArray)
{
MKCoordinateRegion region = { {0.0, 0.0 }, { 0.0, 0.0 } };
region.center.latitude = hospital.lati;
region.center.longitude = hospital.longi;
[self.mapView setRegion:region animated:YES];
DetailMap *hospitalInfo = [[DetailMap alloc] init];
hospitalInfo.title = [hospital name];
hospitalInfo.subtitle = [hospital address];
hospitalInfo.coordinate = region.center;
[self.mapView addAnnotation:hospitalInfo];
}
}
}
-(MKAnnotationView *)mapView:(MKMapView *)mV viewForAnnotation:
(id <MKAnnotation>)annotation {
MKAnnotationView* ann = nil;
if(annotation != mapView.userLocation)
{
ann = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:#"try"];
ann.canShowCallout = YES;
ann.image = [UIImage imageNamed:#"arrow.png"];
UIButton* butt = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
[butt addTarget:self action:#selector(displayArrow:) forControlEvents:
UIControlEventTouchUpInside];
ann.rightCalloutAccessoryView = butt;
}
return ann;
}
-(void)displayArrow:(id)sender{
MoreHospitalDetailViewController *mhdvc = [[MoreHospitalDetailViewController alloc] initWithNibName:nil bundle:nil];
mhdvc.hospitalArray = ????????
// in the MoreHospitalDetailViewController i have an Array called hospitalArray. I need to insert the selected hospital object (after clicking the particular arrow) to this array and pass it to the next view. How to do it ? //
[self.navigationController pushViewController:mhdvc animated:YES];
}
In the MoreHospitalDetailViewController i have an Array called hospitalArray. I need to insert the selected hospital object (after clicking the particular arrow) to this array and pass it to the next view. How to do it ?
note: There can be many items (annotations) in the map, so how do i know which hospital Object i clicked when i am in the (void)displayArrow:(id)sender method ?
Help i am lost

Answer 1

In the displayArrow: method, you can get a reference to the annotation that was clicked using:
DetailMap *hospitalInfo
= (DetailMap *)[mapView.selectedAnnotations objectAtIndex:0];
Note you can also use the map view's calloutAccessoryControlTapped delegate method instead of doing addTarget and writing a custom method. For example:
-(void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view
calloutAccessoryControlTapped:(UIControl *)control
{
DetailMap *hospitalInfo = (DetailMap *)view.annotation;
//do something with the annotation...
}
You have two classes:
Hospital which contains the full details of a hospital including phone#, etc.
DetailMap which implements MKAnnotation and contains just a hospital's coordinate, name, and address (but not the phone# or anything else)
When tapping the callout button of an annotation, you want to get access to the full hospital info (not just coordinate, name, and address).
First, when you say in the comments "DetailMap which only contains 2 records", you really mean "fields" or "properties" instead of "records" (each hospital object is a "record").
Here are a couple of ways to solve this:
In DetailMap, add a property called say hospital of type Hospital and set it when creating DetailMap objects in the callingMap method (hospitalInfo.hospital = hospital). Then in the displayArrow: method, you can add that property to the array (mhdvc.hospitalArray = [NSArray arrayWithObject:hospitalInfo.hospital];).
Change the Hospital class so that it implements MKAnnotation itself and eliminate the DetailMap class entirely. Then you can directly pass Hospital objects to addAnnotation and in the displayArrow: method you would do this:
Hospital *hospital = (Hospital *)[mapView.selectedAnnotations objectAtIndex:0];
mhdvc.hospitalArray = [NSArray arrayWithObject:hospital];
The first option is easier since you've already created the DetailMap class but the second one is cleaner.
Still, the MoreHospitalDetailViewController doesn't need an array to pass the single hospital object (which contains multiple fields). You could just declare a Hospital *hospital property in MoreHospitalDetailViewController to pass the single object.