swift地图定位（十五）使用MKUserTrackingBarButtonItem

准备：在控制器上嵌入一个Navigation Controller，在viewDidLoad中加入下面两句

        let item = MKUserTrackingBarButtonItem(mapView: mapView)

        navigationItem.leftBarButtonItem = item

import UIKit
import MapKit

class ViewController: UIViewController {
    
    @IBOutlet weak var mapView: MKMapView!
    
    lazy var locationM: CLLocationManager = {
        let locationM = CLLocationManager()
        if #available(iOS 8.0, *) {
            locationM.requestAlwaysAuthorization()
        }
        return locationM
    }()
    
    lazy var geoCoder: CLGeocoder = {
        return CLGeocoder()
    }()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        mapView.delegate = self
        mapView.userTrackingMode = MKUserTrackingMode.followWithHeading
        _ = locationM
        let item = MKUserTrackingBarButtonItem(mapView: mapView)
        navigationItem.leftBarButtonItem = item
    }
    
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?){
        let point = touches.first?.location(in: mapView)
        let coordinate = mapView.convert(point!, toCoordinateFrom: mapView)
        let annotation = addAnnotation(coordinate, title: "title", subTitle: "subTitle")
        let location = CLLocation(latitude: coordinate.latitude, longitude: coordinate.longitude)
        geoCoder.reverseGeocodeLocation(location) { (pls: [CLPlacemark]?, error: Error?) -> Void in
            if error == nil {
                let pl = pls?.first
                print(pl)
                annotation.title = pl?.locality
                annotation.subtitle = pl?.name
            }
        }
    }
    
    func addAnnotation(_ coordinate: CLLocationCoordinate2D, title: String, subTitle: String) -> TGAnnotation {
        let annotation: TGAnnotation = TGAnnotation()
        annotation.coordinate = coordinate
        annotation.title = title
        annotation.subtitle = subTitle
        mapView.addAnnotation(annotation)
        return annotation
    }
}

class TGAnnotation: NSObject, MKAnnotation {
    var coordinate: CLLocationCoordinate2D = CLLocationCoordinate2DMake(0, 0)
    var title: String?
    var subtitle: String?
}

extension ViewController: MKMapViewDelegate {
    func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView) {
        let annotation = view.annotation
        if #available(iOS 9.0, *) {
            (view.detailCalloutAccessoryView as! UILabel).text = (annotation?.subtitle)!
        }
        print("选中了\(annotation?.subtitle)")
    }
    
    func mapView(_ mapView: MKMapView, didDeselect view: MKAnnotationView) {
        let annotation = view.annotation
        print("取消选中了\(annotation?.subtitle)")
    }
    
    func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
        let iden = "item"
        var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: iden)
        if annotationView == nil {
            annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: iden)
        }
        annotationView?.annotation = annotation
        annotationView?.image = UIImage(named: "category_1")
        annotationView?.centerOffset = CGPoint(x: 0, y: 0)
        annotationView?.canShowCallout = true
        annotationView?.calloutOffset = CGPoint(x: -10, y: 10)
        
        let imageView = UIImageView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
        let image = UIImage(named: "category_2")
        imageView.image = image
        annotationView?.leftCalloutAccessoryView = imageView
        
        let imageView2 = UIImageView(frame: CGRect(x: 0, y: 0, width: 40, height: 40))
        let image2 = UIImage(named: "category_3")
        imageView2.image = image2
        annotationView?.rightCalloutAccessoryView = imageView2
        
        if #available(iOS 9.0, *) {
            let detailLabel : UILabel = UILabel()
            detailLabel.frame = CGRect(x: 0, y: 0, width: 100, height: 40)
            detailLabel.numberOfLines = 0
            annotationView?.detailCalloutAccessoryView = detailLabel
        }
        annotationView?.isDraggable = true
        return annotationView
    }
}