Passing in values to a closure function - ios

Question

Check out this code:
func getReversedGeocodeLocation(location: CLLocation, completionHandler: #escaping ()->()) {
CLGeocoder().reverseGeocodeLocation(location, completionHandler: {(placemarks, error) -> Void in
if error != nil {
print("Reverse geocoder failed with error" + error!.localizedDescription)
return
}
if placemarks != nil {
if placemarks!.count > 0 {
let pm = placemarks![0]
if let addressDictionary: [AnyHashable: Any] = pm.addressDictionary,
let addressDictionaryFormatted = addressDictionary["FormattedAddressLines"] {
let address = (addressDictionaryFormatted as AnyObject).componentsJoined(by: ", ")
self.addressInViewController = address
}
completionHandler()
}
} else {
print("Problem with the data received from geocoder")
}
})
}
In the viewController
override func viewDidLoad() {
var addressInViewController = String()
getReversedGeocodeLocation(location: location, completionHandler: {
print("After geo finished")
})
}
This is a simple case for using closures. As you can see, when the reverse geo finishes, it updates the addressInViewController variable which is defined outside the function itself. I'm a bit confused when it comes to closures but I do know it's essentially passing in another function as a parameter, into a function. So can I pass in something like (_ String: x)->() instead of ()->() where the address variable would be populated from the main reverse geo function and passed along? I tried doing that but it says "x" is undefined. If this is achieve-able then I guess I can decouple my code in a better way using closures.
Thanks and have a great day :)

Answer 1

define your methods like this
func getReversedGeocodeLocation(location: CLLocation, completionHandler: #escaping (_ value : Any)->()) {
CLGeocoder().reverseGeocodeLocation(location, completionHandler: {(placemarks, error) -> Void in
if error != nil {
print("Reverse geocoder failed with error" + error!.localizedDescription)
return
}
if placemarks != nil {
if placemarks!.count > 0 {
let pm = placemarks![0]
if let addressDictionary: [AnyHashable: Any] = pm.addressDictionary,
let addressDictionaryFormatted = addressDictionary["FormattedAddressLines"] {
let address = (addressDictionaryFormatted as AnyObject).componentsJoined(by: ", ")
self.addressInViewController = address
}
completionHandler(address)
}
} else {
print("Problem with the data received from geocoder")
}
})
}
override func viewDidLoad() {
var addressInViewController = String()
getReversedGeocodeLocation(location: location, completionHandler: { (_ values : Any) in
self. addressInViewController = values
})
}
Make dataType of Value according to your need.