Why calloutAccessoryControlTapped is called for tap on annotation view also?

问题

I have a map on my view controller and I don't know why but the delegate calloutAccessoryControlTapped is also called when I just tap on annotation view, not only when I tap on detail closure. So why this behavior?

import UIKit
import MapKit

extension MapVC: MKMapViewDelegate, CLLocationManagerDelegate
{    
    func mapView(mapView: MKMapView, annotationView view: MKAnnotationView, calloutAccessoryControlTapped control: UIControl)
    {
        ...
    }

}

回答1:

As per Apple developer docs:

Accessory views contain custom content and are positioned on either side of the annotation title text. If a view you specify is a descendant of the UIControl class, the map view calls this method as a convenience whenever the user taps your view. You can use this method to respond to taps and perform any actions associated with that control. For example, if your control displayed additional information about the annotation, you could use this method to present a modal panel with that information.

If your custom accessory views are not descendants of the UIControl class, the map view does not call this method.

So is your accessory view inherited from UIControl?

Reference: https://developer.apple.com/library/ios/documentation/MapKit/Reference/MKMapViewDelegate_Protocol/#//apple_ref/occ/intfm/MKMapViewDelegate/mapView:annotationView:calloutAccessoryControlTapped:

回答2:

Massimo Polimeni seems to be correct. There appears to be a problem with the rightCalloutAccessoryView, but not with the leftCalloutAccessoryView.

The code below (with a leftCalloutAccessoryView) works as expected. If you tap the left accessory, it prints "left accessory selected". If you tap the callout title, it doesn't print anything.

If you use a rightCalloutAccessoryView (commented out, below) and tap the right accessory, it prints "right accessory selected". If you tap the callout title, it also prints "right accessory selected". This does not seem correct.

import UIKit
import MapKit

class ViewController: UIViewController, MKMapViewDelegate {

    @IBOutlet weak var mapView: MKMapView!

    override func viewDidLoad() {
        super.viewDidLoad()

        let annotation = MKPointAnnotation()
        annotation.coordinate = CLLocationCoordinate2D(latitude: 50.29, longitude: -107.79)
        annotation.title = "Swift Current"

        mapView.addAnnotation(annotation)
        mapView.mapType = .standard
        mapView.delegate = self
        mapView.region = MKCoordinateRegion(
            center: CLLocationCoordinate2D(latitude: annotation.coordinate.latitude,
                                           longitude: annotation.coordinate.longitude),
            span: MKCoordinateSpan(latitudeDelta: 1.0, longitudeDelta: 1.0)
        )
    }

    func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
        let reuseId = "Annotation"
        var view = mapView.dequeueReusableAnnotationView(withIdentifier: reuseId)
        if view == nil {
            view = MKPinAnnotationView(annotation: annotation, reuseIdentifier: reuseId)
            view?.canShowCallout = true
            view?.leftCalloutAccessoryView = UIButton(type: .detailDisclosure)
            //view?.rightCalloutAccessoryView = UIButton(type: .detailDisclosure)
        } else {
            view?.annotation = annotation
        }
        return view
    }

    func mapView(_ mapView: MKMapView, annotationView view: MKAnnotationView, calloutAccessoryControlTapped control: UIControl) {
        if control == view.leftCalloutAccessoryView {
            print("left accessory selected")
        } else if control == view.rightCalloutAccessoryView {
            print("right accessory selected")
        }
    }
}

来源：https://stackoverflow.com/questions/36432782/why-calloutaccessorycontroltapped-is-called-for-tap-on-annotation-view-also

标签

ios

swift

mapkit