搜索位置并添加用户位置时如何放大？

Question

func searchBarSearchButtonClicked(_ searchBar: UISearchBar){
    searchBar.resignFirstResponder()
    dismiss(animated: true, completion: nil)
    if self.mapView.annotations.count != 0{
        annotation = self.mapView.annotations[0]
        self.mapView.removeAnnotation(annotation)
    }
    localSearchRequest = MKLocalSearchRequest()
    localSearchRequest.naturalLanguageQuery = searchBar.text
    localSearch = MKLocalSearch(request: localSearchRequest)
    localSearch.start { (localSearchResponse, error) -> Void in

        if localSearchResponse == nil{
            let alertController = UIAlertController(title: nil, message: "Place Not Found", preferredStyle: UIAlertControllerStyle.alert)
            alertController.addAction(UIAlertAction(title: "Dismiss", style: UIAlertActionStyle.default, handler: nil))
            self.present(alertController, animated: true, completion: nil)
            return
        }
        self.pointAnnotation = MKPointAnnotation()
        self.pointAnnotation.title = searchBar.text
        self.pointAnnotation.coordinate = CLLocationCoordinate2D(latitude: localSearchResponse!.boundingRegion.center.latitude, longitude:     localSearchResponse!.boundingRegion.center.longitude)


        self.pinAnnotationView = MKPinAnnotationView(annotation: self.pointAnnotation, reuseIdentifier: nil)
        self.mapView.centerCoordinate = self.pointAnnotation.coordinate
        self.mapView.addAnnotation(self.pinAnnotationView.annotation!)

Answer 1

使用

let span = MKCoordinateSpanMake(0.003, 0.003)
let region = MKCoordinateRegionMake(self.pointAnnotation.coordinate, span)
mapView.setRegion(region, animated:true)

而不是

mapView.centerCoordinate = self.pointAnnotation.coordinate