Add a statement for a function in Swift - ios

Question

I have a label named "direction". I have a map with a lot of pins. When i click on one pin and tap the label "direction" it give me two options and works fine. But when i do not click on a Pin and tap de label "direction" the app crash.
i want to setup an statement when the a pin is not selected an alert show that the user first select a pin to get directions.
Hope someone can look at code to make this possible:
import UIKit
import MapKit
class ViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate, GMSMapViewDelegate {
#IBOutlet weak var mapView: GMSMapView!
#IBAction func MapType(sender: AnyObject) {
let segmentedControl = sender as! UISegmentedControl
switch segmentedControl.selectedSegmentIndex {
case 0:
mapView.mapType = kGMSTypeNormal
case 1:
mapView.mapType = kGMSTypeSatellite
case 2:
mapView.mapType = kGMSTypeHybrid
default:
mapView.mapType = mapView.mapType
}
}
let locationManager = CLLocationManager()
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
//3
mapView.delegate = self
locationManager.delegate = self
locationManager.requestWhenInUseAuthorization()
var Marker= GMSMarker()
Marker.position = CLLocationCoordinate2DMake(5.2317, 4.5708 )
Marker.title = "1"
Marker.snippet = "1"
Marker.appearAnimation = kGMSMarkerAnimationPop
Marker.map = mapView
var Marker1= GMSMarker()
Marker1.position = CLLocationCoordinate2DMake(5.2317, 8.5708 )
Marker1.title = "2"
Marker1.snippet = "2"
Marker1.map = mapView
let label = UILabel(frame: CGRectMake(view.frame.size.width - 100, view.frame.size.height - 40, 80, 30))
label.backgroundColor = UIColor.whiteColor()
label.text = "direction"
label.textAlignment = .Center
label.layer.cornerRadius = 10
label.clipsToBounds = true
label.userInteractionEnabled = true
let tap = UITapGestureRecognizer(target: self, action: "directionTapped")
label.addGestureRecognizer(tap)
mapView!.settings.consumesGesturesInView = false
mapView!.addSubview(label)
mapView!.bringSubviewToFront(label)
self.view.addSubview(label)
}
func directionTapped() {
let openMapsActionSheet = UIAlertController(title: "Open in Maps", message: "Choose a maps application", preferredStyle: .ActionSheet)
openMapsActionSheet.addAction(UIAlertAction(title: "Apple Maps", style: .Default, handler: { (action: UIAlertAction!) -> Void in
let placemark = MKPlacemark(coordinate: CLLocationCoordinate2DMake(self.mapView!.selectedMarker.position.latitude, self.mapView!.selectedMarker.position.longitude), addressDictionary: nil)
let item = MKMapItem(placemark: placemark)
let options = [MKLaunchOptionsDirectionsModeKey:
MKLaunchOptionsDirectionsModeDriving,
MKLaunchOptionsShowsTrafficKey: true]
item.openInMapsWithLaunchOptions(options as [NSObject : AnyObject])
}))
openMapsActionSheet.addAction(UIAlertAction(title: "Google Maps", style: .Default, handler: { (action: UIAlertAction!) -> Void in
if (UIApplication.sharedApplication().canOpenURL(NSURL(string:"comgooglemaps://")!)) {
UIApplication.sharedApplication().openURL(NSURL(string:
"comgooglemaps://?daddr=\(self.mapView!.selectedMarker.position.latitude),\(self.mapView!.selectedMarker.position.longitude)")!)
} else {
UIApplication.sharedApplication().openURL(NSURL(string:
"http://maps.google.com/maps?daddr=\(self.mapView!.selectedMarker.position.latitude),\(self.mapView!.selectedMarker.position.longitude)")!)
}
}))
openMapsActionSheet.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: nil))
presentViewController(openMapsActionSheet, animated: true, completion: nil)
}
// 1
func locationManager(manager: CLLocationManager!, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
// 2
if status == .AuthorizedWhenInUse {
// 3
locationManager.startUpdatingLocation()
//4
mapView.myLocationEnabled = true
mapView.settings.myLocationButton = true
}
}
// 5
func locationManager(manager: CLLocationManager!, didUpdateLocations locations: [AnyObject]!) {
if let location = locations.first as? CLLocation {
// 6
mapView.camera = GMSCameraPosition(target: location.coordinate, zoom: 6, bearing: 1, viewingAngle: 1)
// 7
locationManager.stopUpdatingLocation()
}
}
}

Answer 1

In absence of the complete code, here is what i can extrapolate:
I am assuming you have a mapView that is already set.
I am assuming mapView!.selectedMarker gets populated only when the user selects the pin, else it is nil (or some other value u choose) then,
Now, directionTapped should be:
if self.mapView!.selectedMarker != nil {
<Your current Code>
} else {
<Code to Show the new alert about pin not selected>
}

Answer 2

with this code it worked from me:
func directionTapped(){
//code input from Apple-and-Oranges
if self.mapView!.selectedMarker != nil {
//current code
let openMapsActionSheet = UIAlertController(title: "Open in Maps", message: "Choose a maps application", preferredStyle: .ActionSheet)
openMapsActionSheet.addAction(UIAlertAction(title: "Apple Maps", style: .Default, handler: { (action: UIAlertAction!) -> Void in
let placemark = MKPlacemark(coordinate: CLLocationCoordinate2DMake(self.mapView!.selectedMarker.position.latitude, self.mapView!.selectedMarker.position.longitude), addressDictionary: nil)
let item = MKMapItem(placemark: placemark)
let options = [MKLaunchOptionsDirectionsModeKey:
MKLaunchOptionsDirectionsModeDriving,
MKLaunchOptionsShowsTrafficKey: true]
item.openInMapsWithLaunchOptions(options as [NSObject : AnyObject])
}))
openMapsActionSheet.addAction(UIAlertAction(title: "Google Maps", style: .Default, handler: { (action: UIAlertAction!) -> Void in
if (UIApplication.sharedApplication().canOpenURL(NSURL(string:"comgooglemaps://")!)) {
UIApplication.sharedApplication().openURL(NSURL(string:
"comgooglemaps://?daddr=\(self.mapView!.selectedMarker.position.latitude),\(self.mapView!.selectedMarker.position.longitude)")!)
} else {
UIApplication.sharedApplication().openURL(NSURL(string:
"http://maps.google.com/maps?daddr=\(self.mapView!.selectedMarker.position.latitude),\(self.mapView!.selectedMarker.position.longitude)")!)
}
}))
openMapsActionSheet.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: nil))
presentViewController(openMapsActionSheet, animated: true, completion: nil)
}
//Added a alert message
else {
let alertController = UIAlertController(title: "Choose Pin!", message: "\nChoose Pin to get navigation from current location", preferredStyle: .Alert)
alertController.addAction(UIAlertAction(title: "Cancel", style: .Default, handler: { (action: UIAlertAction!) in
}))
presentViewController(alertController, animated: true, completion: nil)
}
}