swift - iOS - How can I return latitude and longitude? -

i can't return latitude , longitude. 0.0 , 0.0.

what can these values?

code :

func forwardgeocoding (address: string) -> (double, double) { let geocoder = clgeocoder()  var latitude: double = 0.0 var longitude: double = 0.0  geocoder.geocodeaddressstring(address) { (placemarks: [clplacemark]?, error: nserror?) -> void in      if error != nil {         print(error?.localizeddescription)     } else {         if placemarks!.count > 0 {             let placemark = placemarks![0] clplacemark             let location = placemark.location              latitude = double((location?.coordinate.latitude)!)             longitude = double((location?.coordinate.longitude)!)              print("before : \(latitude, longitude)")          }     } }  print("after : \(latitude, longitude)") return (latitude, longitude) } 

this viewdidload:

override func viewdidload() {     super.viewdidload()   forwardgeocoding("new york, ny, united states")  } 

result:

after : (0.0, 0.0)

before : (40.713054, -74.007228)

the problem code geocoding requests asynchronous, return statement executed before geocoding results retrieved.

i'd use 1 of 2 options fix this. first, instead of returning tuple, make own completion handler, , call after placemark found:

func forwardgeocoding (address: string, completion: (cllocationcoordinate2d) -> void) {     let geocoder = clgeocoder()     geocoder.geocodeaddressstring(address) { (placemarks: [clplacemark]?, error: nserror?) -> void in          if error != nil {             print(error?.localizeddescription)         } else {             if placemarks!.count > 0 {                 let placemark = placemarks![0] clplacemark                 let location = placemark.location                 completion(location.coordinate)             }         }     } } 

now when call function can provide completion relevant values wherever you're calling function.

if function method in class , never needs called class, have set properties of class, , properties have didset blocks. example:

class someclass {     var coordinates: cllocationcoordinate2d {         didset {             dosomethingwithcoordinates()         }     }      private func forwardgeocoding (address: string, completion: (cllocationcoordinate2d) -> void) {         let geocoder = clgeocoder()         geocoder.geocodeaddressstring(address) { (placemarks: [clplacemark]?, error: nserror?) -> void in              if error != nil {                 print(error?.localizeddescription)             } else {                 if placemarks!.count > 0 {                     let placemark = placemarks![0] clplacemark                     let location = placemark.location                     self.coordinates = location.coordinate                 }             }         }     } } 

the first options more versatile, second avoids having completion blocks withing completion blocks, can become confusing keep track of in code.