将UIMapView委托设置为self会触发警告，但可以

Question

In my project, I have a MapView that I add annotations to. I need those annotations to have different images, so I use the - (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation method. However, for this to work I need the MapView's delegate to be set to self . So I use this line in the viewDidLoad function:

self.viewMap.delegate = self;

This works as expected, however XCode is warning me with this message:

Assigning to 'id<MKMapViewDelegate>' from incompatible type 'ViewController *const__strong'

I'm guessing that I am not going about this the proper way, and that's why there's a warning. So what am I doing wrong?

Answer 1

Your ViewController class—which you might consider renaming to something more descriptive—needs to declare conformance to MKMapViewDelegate in its interface:

@interface ViewController : UIViewController <MKMapViewDelegate>

// stuff

@end