Get Latitude and longitude center of Google Map

Question

I want to show full screen mapView, always get Latitude and longitude of center of mapView and show marker in this point.

func mapView(_ mapView: GMSMapView, didChange position: GMSCameraPosition) {

    let lat = mapView.camera.target.latitude
    print(lat)

    let lon = mapView.camera.target.longitude
    print(lon)


    marker.position = CLLocationCoordinate2DMake(CLLocationDegrees(centerPoint.x) , CLLocationDegrees(centerPoint.y))
    marker.map = self.mapView
    returnPostionOfMapView(mapView: mapView)

  }

  func mapView(_ mapView: GMSMapView, idleAt position: GMSCameraPosition) {
    print("idleAt")

    //called when the map is idle

    returnPostionOfMapView(mapView: mapView)

  }

  func returnPostionOfMapView(mapView:GMSMapView){
    let geocoder = GMSGeocoder()
    let latitute = mapView.camera.target.latitude
    let longitude = mapView.camera.target.longitude




    let position = CLLocationCoordinate2DMake(latitute, longitude)
    geocoder.reverseGeocodeCoordinate(position) { response , error in
      if error != nil {
        print("GMSReverseGeocode Error: \(String(describing: error?.localizedDescription))")
      }else {
        let result = response?.results()?.first
        let address = result?.lines?.reduce("") { $0 == "" ? $1 : $0 + ", " + $1 }

        print(address)
//        self.searchBar.text = address
      }
    }
  }

i use this code in how can know Latitude and longitude that return in returnPostionOfMapView method is position of center mapView and show marker in this position?

Answer 1

You are doing it right to get the center of the map by using the google maps's func mapView(_ mapView: GMSMapView, didChange position: GMSCameraPosition) delegate.

Take a variable for center coordinates

var centerMapCoordinate:CLLocationCoordinate2D!

Implement this delegate to know the center position.

func mapView(_ mapView: GMSMapView, didChange position: GMSCameraPosition) {
    let latitude = mapView.camera.target.latitude
    let longitude = mapView.camera.target.longitude
    centerMapCoordinate = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
    self.placeMarkerOnCenter(centerMapCoordinate:centerMapCoordinate)
}

Function to place a marker on center point

func placeMarkerOnCenter(centerMapCoordinate:CLLocationCoordinate2D) {
    let marker = GMSMarker()
    marker.position = centerMapCoordinate
    marker.map = self.mapView
}

In this case you will get a lot of markers. So keep a global hold of marker and check if it is already present, just change the position

var marker:GMSMarker!

func placeMarkerOnCenter(centerMapCoordinate:CLLocationCoordinate2D) {
    if marker == nil {
        marker = GMSMarker()
    }
    marker.position = centerMapCoordinate
    marker.map = self.mapView
}