错误“调用中缺少参数'coordinate‘的参数”

Question

我有一个自定义的MkAnnotation，它有一个标题、副标题和与之相关的额外信息，以便在地图视图上使用。我正在将此信息传递给另一个UIViewController。然而，我为引脚分配的坐标似乎有一些问题。该错误在下面代码行"var bridge17pin = MyAnnotation()“上的引脚设置信息中突出显示。

   override func viewDidLoad() {
    super.viewDidLoad()

    //for users location
    myLocMgr.desiredAccuracy = kCLLocationAccuracyBest
    myLocMgr.requestWhenInUseAuthorization()
    myLocMgr.startUpdatingLocation()
    myLocMgr.delegate = self
    mapView.delegate = self



 //coordinate for pin
 var bridge17 = CLLocationCoordinate2DMake(53.346061, -6.227379)


       //custom MKAnnotation
       class MyAnnotation: NSObject, MKAnnotation {
        @objc var coordinate: CLLocationCoordinate2D
        var EXTRA_INFORMATION: String?
        var title: String?

        init(coordinate: CLLocationCoordinate2D) {
           self.coordinate = coordinate
        }
    }



    //setting information of pin
    var bridge17pin = MyAnnotation()
    bridge17pin.coordinate = bridge17
    bridge17pin.title = "The bridge"
    bridge17pin.subtitle = "hello this is the bridge"
    bridge17pin.EXTRA_INFORMATION = "this was built in 2010"
    mapView.addAnnotation(bridge17pin)
      }

Answer 1

因为您必须在实例化时发送坐标。因此，在代码中替换

var bridge17pin = MyAnnotation()

使用

var bridge17pin = MyAnnotation(coordinate: bridge17)

对于那个subTitle see this link