使用注释针创建长按手势识别器

Question

到目前为止，我所做的是创建地图。然后显示用户位置并将其居中，以便在旅行（汽车等）时地图居中

但现在我想添加一个长按手势，这样如果用户进行输入，就会删除一个 pin。我一直在努力学习教程并且模拟器崩溃了。

如何添加 longPressGesturerecognizer 以便它在我的 mapView 上放置一个图钉。

这是我的代码-

import UIKit
import MapKit
import CoreLocation

class Page2: UIViewController, MKMapViewDelegate,  CLLocationManagerDelegate{

    @IBOutlet var mapView: MKMapView!
    let locationManager = CLLocationManager()

    override func viewDidLoad() {
        super.viewDidLoad()
        self.locationManager.delegate = self
        self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
        self.locationManager.requestWhenInUseAuthorization()
        self.locationManager.startUpdatingLocation()
        //blue dot on the map
        self.mapView.showsUserLocation = true
        //tracking mode on
        self.mapView.userTrackingMode = .follow
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // location Manager Delegate center user on map
    private func locationManager(manager: CLLocationManager!, didUpdateLocations locations: [AnyObject]!) {

        let location = locations.last
        let center = CLLocationCoordinate2D(latitude: location!.coordinate.latitude, longitude: (location?.coordinate.longitude)!)
        let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.005, longitudeDelta: 0.005)) //zoom on map
        self.mapView.setRegion(region, animated: true)
        self.locationManager.stopUpdatingLocation()
    }

    // print errors
    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error){
        print("Errors: " + error.localizedDescription)
    }
}

Answer 1

首先在Swift 3 中CLLocationManagerDelegate 方法的locationManager(_:didUpdateLocations:) 的签名被改变了，所以你需要改变那个方法如下。

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
     //your code and don't forgot to remove private
}

您可以像这样使用longGesture 和mapView，首先在mapView 中使用addGestureRecognizer 在viewDidLoad 中。

let longPressGesture = UILongPressGestureRecognizer(target: self, action: #selector(addAnnotationOnLongPress(gesture:)))
longPressGesture.minimumPressDuration = 1.0
self.mapView.addGestureRecognizer(longPressGesture)

现在为 UILongPressGestureRecognizer 添加操作。

@objc func addAnnotationOnLongPress(gesture: UILongPressGestureRecognizer) {

    if gesture.state == .ended {
        let point = gesture.location(in: self.mapView)
        let coordinate = self.mapView.convert(point, toCoordinateFrom: self.mapView)
        print(coordinate)
        //Now use this coordinate to add annotation on map.
        var annotation = MKPointAnnotation()
        annotation.coordinate = coordinate
        //Set title and subtitle if you want
        annotation.title = "Title" 
        annotation.subtitle = "subtitle" 
        self.mapView.addAnnotation(annotation)
    }
}

Answer 2

您也可以使用轻击手势来放置图钉。

添加点击手势

    let tapGesture = UITapGestureRecognizer(target: self, action:#selector(AddressViewController.handleTap(_:)))
    tapGesture.delegate = self
    mapView.addGestureRecognizer(tapGesture)

在手势上放置图钉

func handleTap(_ sender: UIGestureRecognizer)
{
  if sender.state == UIGestureRecognizerState.ended {

        let touchPoint = sender.location(in: mapView)
        let touchCoordinate = mapView.convert(touchPoint, toCoordinateFrom: mapView)
        let annotation = MKPointAnnotation()
        annotation.coordinate = touchCoordinate
        annotation.title = "Event place"
        mapView.removeAnnotations(mapView.annotations)
    mapView.addAnnotation(annotation) //drops the pin
  }
}

Answer 3

我认为这个更新的小代码有助于其他人通过长按放置引脚来实现注释：

    import UIKit
    import MapKit
    class ViewController: UIViewController, MKMapViewDelegate {

        @IBOutlet weak var map: MKMapView!

        override func viewDidLoad() {
            super.viewDidLoad()

            let uilpgr = UILongPressGestureRecognizer(target: self, action: #selector(longPressed(gestureRecognized:)))

            //long press (2 sec duration)
            uilpgr.minimumPressDuration = 2
            map.addGestureRecognizer(uilpgr)   
        }

        func longPressed(gestureRecognized: UIGestureRecognizer){
            let touchpoint = gestureRecognized.location(in: self.map)
            let location = map.convert(touchpoint, toCoordinateFrom: self.map)

            let annotation = MKPointAnnotation()
            annotation.title = "Latitude: \(location.latitude)"
            annotation.subtitle = "Longitude: \(location.longitude)"
            annotation.coordinate = location
            map.addAnnotation(annotation)


        }

        override func didReceiveMemoryWarning() {
            super.didReceiveMemoryWarning()
            // Dispose of any resources that can be recreated.
        }


    }