How to get corelocation work - ios

Question

iOS newbie here. I'm adapting code from this tutorial ( http://rshankar.com/get-your-current-address-in-swift/ ) to get reverse geocoding work in my project(coordinate to physical address). My project have two view controllers and the main view controller has a button. I use segue to load the other view controller by overriding prepareforsegue in the main view controller. I have a class that implements CLLocationManagerDelegate. I just create this class to handle all location related functions. I initialize this class inside button pressed event of the main view controller. My problem is that I'm testing my project in iphone simulator and the alert box that asks use for permission to use location service is not shown. So the status parameter of didchangeauthrorization method always contain not determined. I've tried simulate location option but it does not resolve the issue. How do I resolve this?
ViewController.swift (main view)
class ViewController: UIViewController {
#IBAction func gpsButtonPressed(sender: UIButton) {
let coreLocation = CoreLocationController()
coreLocation.getLocation();
}
.....
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)
{
if segue.identifier == "ShowGpsView"
{
if let destinationVC = segue.destinationViewController as? SecondViewController{
destinationVC.msg = "hello"
}
}
}
CoreLocationController.h
import UIKit
import CoreLocation
class CoreLocationController: NSObject, CLLocationManagerDelegate {
var locationManager = CLLocationManager()
var coords: CLLocationCoordinate2D?
override init() {
super.init()
self.locationManager.delegate = self
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
}
func getLocation()
{
if CLLocationManager.authorizationStatus() == .NotDetermined {
self.locationManager.requestWhenInUseAuthorization()
}
}
func locationManager(manager: CLLocationManager!,
didChangeAuthorizationStatus status: CLAuthorizationStatus)
{
if status == .AuthorizedWhenInUse {
manager.startUpdatingLocation()
}
}
func locationManager(manager: CLLocationManager!, didUpdateLocations locations: [AnyObject]!) {
CLGeocoder().reverseGeocodeLocation(manager.location, completionHandler: {(placemarks, error)->Void in
if error != nil {
println("Reverse geocoder failed with error" + error.localizedDescription)
return
}
if placemarks.count > 0 {
let pm = placemarks[0] as! CLPlacemark
self.displayLocationInfo(pm)
} else {
println("Problem with the data received from geocoder")
}
})
}
func displayLocationInfo(placemark: CLPlacemark) {
locationManager.stopUpdatingLocation()
println(placemark.locality)
println(placemark.postalCode)
println(placemark.administrativeArea)
println(placemark.country)
}
}

Answer 1

Add NSLocationWhenInUseUsageDescription (which is a string) to you info.plist file.
Most of these authorisation requests need a corresponding entry in the plist.
When the app doesn't ask for permission it can only be one of three things:
the entry in the info.plist was not there
your app has already asked for permission and you need to reset these. (delete the app and all data, maybe even reset privacy settings)
your location manager / delegate are not set up correctly.
I tested the code posted below and it works. I also made some changes to make it safer/work. Some things might give an error because of Swift 2.0. Just replace them with your own parts.
when asking for the authorisation you also want to be able to catch it when it was denied.
you also want to have a way of starting the update when the authorisation has already been given. So auth changed is not a good way to handle that on it's own
you want to use a delegate method / completion handler to know when it found a location (this can take time, so when you don't the code will continue and crash because no location is found yet)
Updated code :
View
import UIKit
class ViewController: UIViewController, CoreLocationControllerDelegate {
var clTest : CoreLocationController = CoreLocationController()
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(animated: Bool) {
clTest.delegate = self
clTest.getAutorisation()
}
func foundLocation() {
print(clTest.coords)
}
}
Location
import UIKit
import CoreLocation
class CoreLocationController: NSObject, CLLocationManagerDelegate {
var locationManager = CLLocationManager()
var coords: CLLocationCoordinate2D?
var delegate : CoreLocationControllerDelegate?
private var authorised : Bool = false {
didSet {
if authorised == true {
locationManager.startUpdatingLocation()
}
}
}
override init() {
super.init()
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBest
}
func getAutorisation()
{
if CLLocationManager.authorizationStatus() == .NotDetermined {
self.locationManager.requestWhenInUseAuthorization()
} else if CLLocationManager.authorizationStatus() == .AuthorizedWhenInUse {
authorised = true
} else if CLLocationManager.authorizationStatus() == .Denied {
// catch this
}
}
func locationManager(manager: CLLocationManager,
didChangeAuthorizationStatus status: CLAuthorizationStatus)
{
if status == .AuthorizedWhenInUse {
authorised = true
}
}
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
CLGeocoder().reverseGeocodeLocation(manager.location!, completionHandler: {(placemarks, error)->Void in
if error != nil {
print("Reverse geocoder failed with error" + error!.localizedDescription)
return
}
if placemarks!.count > 0 {
let pm = placemarks![0]
self.displayLocationInfo(pm)
} else {
print("Problem with the data received from geocoder")
}
})
}
func displayLocationInfo(placemark: CLPlacemark) {
locationManager.stopUpdatingLocation()
coords = placemark.location!.coordinate
delegate!.foundLocation()
print(placemark.locality)
print(placemark.postalCode)
print(placemark.administrativeArea)
print(placemark.country)
}
}
protocol CoreLocationControllerDelegate {
func foundLocation()
}