我想显示全屏 mapView，始终获取 mapView 中心的纬度和经度并在该点显示标记。

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 
      } 
    } 
  } 

我使用此代码如何知道 returnPostionOfMapView 方法中返回的纬度和经度是中心 mapView 的位置并在此位置显示标记？

请您参考如下方法:

通过使用 google map 的 func mapView(_ mapView: GMSMapView, didChange position: GMSCameraPosition) 委托(delegate)，您正确地获得了 map 的中心。

取中心坐标变量

var centerMapCoordinate:CLLocationCoordinate2D! 

实现此委托(delegate)以了解中心位置。

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) 
} 

在中心点放置标记的功能

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

在这种情况下你会得到很多标记。所以保持全局持有marker并检查它是否已经存在，只需更改位置

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