Adding a pin annotation to a map view on a long pr

问题:

I'm trying to make an iPhone app which requires users to be able to long press on a place on a map view to drop a pin there. Does anybody know how this is done?

The behaviour is observable in apple maps when you long press on the screen. It will drop a pin and present an annotation saying "dropped pin"

回答1:

1) Instantiate a UILongPressGestureRecognizer and add it to the MKMapView.

2) When the selector gets called after the user has a long press, call the addAnnotation method in MKMapView with the appropriate title and coordinate.

3) Then make sure you conform to the MKMapViewDelegate and implement viewForAnnotation: which will be called right after you add the annotation and return a MKPinAnnotationView

回答2:

1. add UILongPressGestureRecognizer to your MapView

   var uilgr = UILongPressGestureRecognizer(target: self, action: "addAnnotation:")
   uilgr.minimumPressDuration = 2.0
   
   map.add (uilgr)
   
   //IOS 9
   map.addGestureRecognizer(uilgr) 
   

2. Add annotation on Long press detect - func:

   func addAnnotation(gestureRecognizer:UIGestureRecognizer){
       if gestureRecognizer.state == UIGestureRecognizerState.Began {
           var touchPoint = gestureRecognizer.locationInView(map)
           var newCoordinates = map.convertPoint(touchPoint, toCoordinateFromView: map)
           let annotation = MKPointAnnotation()
           annotation.coordinate = newCoordinates
   
           CLGeocoder().reverseGeocodeLocation(CLLocation(latitude: newCoordinates.latitude, longitude: newCoordinates.longitude), 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
   
               // not all places have thoroughfare & subThoroughfare so validate those values
               annotation.title = pm.thoroughfare + ", " + pm.subThoroughfare
               annotation.subtitle = pm.subLocality
               self.map.addAnnotation(annotation)
               println(pm)
           }
           else {
               annotation.title = "Unknown Place"
               self.map.addAnnotation(annotation)
               println("Problem with the data received from geocoder")
           }
           places.append(["name":annotation.title,"latitude":"\(newCoordinates.latitude)","longitude":"\(newCoordinates.longitude)"])
       })
   }
   }
   

3. or you can add annotation without any title:

   func action(gestureRecognizer:UIGestureRecognizer){
       var touchPoint = gestureRecognizer.locationInView(map)
       var newCoordinates = map.convertPoint(touchPoint, toCoordinateFromView: map)
       let annotation = MKPointAnnotation()
       annotation.coordinate = newCoordinates
       map.addAnnotation(annotation)
   }
   

回答3:

First declare UIGestureRecognizer in viewDidLoad

let longGesture = UILongPressGestureRecognizer(target: self, action: #selector(addWaypoint(longGesture:)))
mapView.addGestureRecognizer(longGesture)

Second add the function for longPress

@objc func addWaypoint(longGesture: UIGestureRecognizer) {

    let touchPoint = longGesture.location(in: mapView)
    let wayCoords = mapView.convert(touchPoint, toCoordinateFrom: mapView)
    let location = CLLocation(latitude: wayCoords.latitude, longitude: wayCoords.longitude)
    myWaypoints.append(location)

    let wayAnnotation = MKPointAnnotation()
    wayAnnotation.coordinate = wayCoords
    wayAnnotation.title = "waypoint"
    myAnnotations.append(location)
}

I recommend creating the annotations in an array that will serve you later if you want to delete it, like this...

var myAnnotations = [CLLocation]()

If you have different annotations, you can delete only the annotations you want, for that when you add a new annotation add to the array. To delete only one group of annotations just do the following

for dots in myAnnotations{
    mapView.removeAnnotation(dots)
}

To delete all annotations try

mapView.removeAnnotations(mapView.annotations)

Apologies for the translation....

回答4:

Update Swift3

func action(gestureRecognizer:UIGestureRecognizer){
    let touchPoint = gestureRecognizer.location(in: mapView)
    let newCoordinates = mapView.convert(touchPoint, toCoordinateFrom: mapView)
    let annotation = MKPointAnnotation()
    annotation.coordinate = newCoordinates
    mapView.addAnnotation(annotation)
}