How to Increase the Radius of userLocation Annotat

问题:

My app takes user permission and move the map to the location. And at that position by default MapKit add a blue icon which is generating some pulse.
I've searched around but I found how to add a 1000m circle around userLocation. I don't want that. You can say I'm looking to customize the userLocation default annotation. The blue pulse it generates I want to increase that radius. And when this blue pulse hits a custom annotation there should be a method triggered. So how to achieve that?

回答1:

Unfortunately you cannot simply alter the behaviour of the standard annotation; you need to take over display of the annotation view yourself.

The user location is a map annotation of type MKUserLocation. If you implement the MKMapViewDelegate method viewForAnnotation and the map is displaying the user's location then the delegate method will be called with an instance of MKUserLocation - your responsibility is to either return nil, in which case the standard annotation view will be displayed, or return an instance of MKAnnotationView which will be displayed instead.

You can code something like:

- (MKAnnotationView *)mapView:(MKMapView *)mapView
        viewForAnnotation:(id<MKAnnotation>)annotation {
    if ([annotation isKindOfClass:[MKUserLocation class]]) {
        return [[MyPulsingViewAnnotation alloc] initWithUserLocation:annotation];
    }

    return nil;
}

As for performing some animation when the 'pulse' intersects another annotation, you will need to pass the other annotation locations to your pulsing view and check the coordinates when you run the animation.