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How to add annotations to MKMapView using MKPointAnnotation and MKPinAnnotationView

Paul Hudson       @twostraws

Once you have an MKMapView up and running, it only takes a few lines of code more to drop pins containing placemarks.

Start by making your view controller the delegate of your map view, so that we can receive events. You should also make your view controller conform to MKMapViewDelegate in code, like this:

class ViewController: UIViewController, MKMapViewDelegate {

Adding pins to the map takes two code changes. First you need to create an annotation describing where the pin is and what its name is – put this in your viewDidLoad() method:

let london = MKPointAnnotation()
london.title = "London"
london.coordinate = CLLocationCoordinate2D(latitude: 51.507222, longitude: -0.1275)
mapView.addAnnotation(london)

Second, you need to implement a viewFor method that converts your annotation into a view that can be displayed on the map. iOS comes with a built-in view type called MKPinAnnotationView that provides the familiar pin layout, so we can use that here.

Note: For performance reasons, dropping pins onto a map works using re-use identifiers, just like loading table view cells. The code below tries to re-use pins, and you should do the same.

Add this to your view controller:

func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
    guard annotation is MKPointAnnotation else { return nil }

    let identifier = "Annotation"
    var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: identifier)

    if annotationView == nil {
        annotationView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: identifier)
        annotationView!.canShowCallout = true
    } else {
        annotationView!.annotation = annotation
    }

    return annotationView
}

That’s all the code you need!

Available from iOS 4.0

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