Stuck on using MKPinAnnotationView() within Swift and MapKit

Question

I have a working loop to setup annotations for the title and subtitle elements for some working data points. What I want to do within that same loop structure is to set the pin color to Purple instead of the default. What I can't figure out is what I need to do to tap into my theMapView to set the pin accordingly.

My working loop and some attempts at something...

....
for var index = 0; index < MySupplierData.count; ++index {

  // Establish an Annotation
  myAnnotation = MKPointAnnotation();
  ... establish the coordinate,title, subtitle properties - this all works
  self.theMapView.addAnnotation(myAnnotation)  // this works great.

  // In thinking about PinView and how to set it up I have this...
  myPinView = MKPinAnnotationView();      
  myPinView.animatesDrop = true;
  myPinView.pinColor = MKPinAnnotationColor.Purple;  

  // Now how do I get this view to be used for this particular Annotation in theMapView that I am iterating through??? Somehow I need to marry them or know how to replace these attributes directly without the above code for each data point added to the view
  // It would be nice to have some kind of addPinView.  

}

Solution

You need to implement the viewForAnnotation delegate method and return an MKAnnotationView (or subclass) from there.
This is just like in Objective-C -- the underlying SDK works the same way.

Remove the creation of MKPinAnnotationView from the for loop that adds the annotations and implement the delegate method instead.

Here is a sample implementation of the viewForAnnotation delegate method in Swift:

func mapView(mapView: MKMapView!, 
    viewForAnnotation annotation: MKAnnotation!) -> MKAnnotationView! {

    if annotation is MKUserLocation {
        //return nil so map view draws "blue dot" for standard user location
        return nil
    }

    let reuseId = "pin"

    var pinView = mapView.dequeueReusableAnnotationViewWithIdentifier(reuseId) as? MKPinAnnotationView
    if pinView == nil {
        pinView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: reuseId)
        pinView!.canShowCallout = true
        pinView!.animatesDrop = true
        pinView!.pinColor = .Purple
    }
    else {
        pinView!.annotation = annotation
    }

    return pinView
}

Comments

[Kokanee]

Brilliant - Tks. I dropped this right in and it worked. I just needed to see a Swift equivalent as I don't do a lot of Obj C. One minor point in that the compiler threw a warning for using the underscore in the line: func mapView(_ mapView: MKMapView!,... The warning was "Extraneous "_" in paramter 'mapView' has no keyword argument name.

[User4]

@Anna, did you have an example project available? I'm banging my head against the wall here. Thanks

[Lunarchaos42]

I do not have enough rep to comment, but the function above still works except that pinView!.pinColor is not depreciated. It should read pinView!.pinTintColor = UIColor.purpleColor()