Callout action from Annotations in Map view - ios

Question

I have an array of latitudes and longitudes along with other stuffs and I want to create annotations in Map view. I’m using MapKit.
When ever the user clicks the annotation callout I’m going to present another controller. I’m not able to find the index of the array element that was used to create that particular annotation.
Below is my code.
I have a Int variable
var annotationIndex = 0
This is where I add annotations
func addAnnotation(latitude: Double, longitude: Double, title: String, subTitle: String?) {
if (latitude >= -90 && latitude <= 90) && (longitude >= -180 && longitude <= 180) {
let location = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
let span = MKCoordinateSpanMake(0.05, 0.05)
let region = MKCoordinateRegion(center: location, span: span)
mapView.setRegion(region, animated: true)
let annotation = MKPointAnnotation()
annotation.coordinate = location
annotation.title = title
annotation.subtitle = subTitle
mapView.addAnnotation(annotation)
}
}
This is an MKMapViewDelegate method to customize annotation
func mapView(mapView: MKMapView!, viewForAnnotation annotation: MKAnnotation!) -> MKAnnotationView!
{
if !(annotation is MKPointAnnotation)
{
return nil
}
let reuseId = "test"
var aView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: reuseId)
aView.canShowCallout = true
let btn = UIButton.buttonWithType(UIButtonType.DetailDisclosure) as! UIButton
btn.addTarget(self, action: "btnDisclosureAction:", forControlEvents: UIControlEvents.TouchUpInside)
btn.tag = annotationIndex
annotationIndex++
aView.rightCalloutAccessoryView = btn
return aView
}
This is the rightCalloutAccessoryView Button Action
func btnDisclosureAction(sender: UIButton) {
println(sender.tag)
}
Right now I'm just printing the callout diusclosure button tag which I try setting it using an annotationIndex variable.
Since the annotationView is reused I cannot get the exact index value.Is there a better way to do it?

Answer 1

Subclass MKPointAnnotation to have index value.
class
Annotation : MKPointAnnotation {
var index = 0
}
And set index when annotation is created.
let annotation = Annotation()
:
annotation.subtitle = subTitle
annotation.index = annotationIndex++
Pass annotation's index to btn
btn.addTarget(self, action: "btnDisclosureAction:", forControlEvents: UIControlEvents.TouchUpInside)
btn.tag = ( annotation as! Annotation ).index
EDIT:
So your viewForAnnotation will be
func mapView(mapView: MKMapView!, viewForAnnotation annotation: MKAnnotation!) -> MKAnnotationView!
{
if !(annotation is Annotation)
{
return nil
}
let reuseId = "test"
var aView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: reuseId)
aView.canShowCallout = true
let btn = UIButton.buttonWithType(UIButtonType.DetailDisclosure) as! UIButton
btn.addTarget(self, action: "btnDisclosureAction:", forControlEvents: UIControlEvents.TouchUpInside)
btn.tag = ( annotation as! Annotation ).index
aView.rightCalloutAccessoryView = btn
return aView
}

Answer 2

Specify indexselected as class variable and initilise it with -1 in viewDidLoad method ,like
override func viewDidLoad() {
super.viewDidLoad()
indexselected = -1
}
You can get your annotation index while user tap on annotation, and didSelectAnnotationView method get called automatically.
func mapView(mapView: MKMapView!, didSelectAnnotationView view: MKAnnotationView!) {
var selectedAnnotation : MKPointAnnotation = MKPointAnnotation()
selectedAnnotation = view.annotation as! MKPointAnnotation
for var i = 0; i<yourlist.count ; i++ {
let strtitle : String = yourlist.objectAtIndex(i).title as! String
if selectedAnnotation.title == strtitle {
indexselected=i
break
}
}
}
We can get annotation index by comparing title on annotation and title from your array, and save the index from array. On selection of button method you can use that index.
func btnDisclosureAction(sender: UIButton) {
println(indexselected)
}
Hope this help you.