不知道它在哪里,或者如果我们应该使用一些其他的MK方法.任何帮助是赞赏.

func refreshlocation(lat:String,lon:String,withOffset:Bool = false){


        // 1 Convert the string values to something that can be used.
        let location = CLLocationCoordinate2D(
            latitude: (lat as NSString).doubleValue as CLLocationDegrees,longitude: (lon as NSString).doubleValue as CLLocationDegrees
        )

        // 2 setup some initial variables.
        let span = MKCoordinateSpanMake(
            (self.locationLatitudeDelta as NSString).doubleValue as CLLocationDegrees,(self.locationLongitudeDelta as NSString).doubleValue as CLLocationDegrees
        )

        let region = MKCoordinateRegion(center: location,span: span)
        mapView.setRegion(region,animated: true)

        //3 decorate the point and add the point to the map.
        var annotation = MKPointAnnotation()
        annotation.setCoordinate(location) //Error on this line

    }