[Swift] Templates and explanations of basic functions using Map Kit View

What is this

Something like a template to write to the controller when Map Kit View is installed and its explanation. It is assumed that there are ** Map Kit View ** and ** Label ** on one screen, and if you press and hold a specific part of the map, the address will be displayed in the Lebel part.

Templates and explanations

ViewController.swift

import UIKit

//The following two are required to use Map Kit View
import MapKit
import CoreLocation

//Declare two protocols
class ViewController: UIViewController,CLLocationManagerDelegate, UIGestureRecognizerDelegate {

  //Define a variable that contains an address
  var addressString = ""
  
  //Recognize long press
  @IBOutlet var longPress: UILongPressGestureRecognizer!
  
  //Connect Map Kit View from the storyboard by pressing and holding the Control key
  @IBOutlet weak var mapView: MKMapView!
  
  //Create an instance to get location information
  var locationManager:CLLocationManager!
  
  //Connect Label from the storyboard by pressing and holding the Control key
  @IBOutlet weak var addressLabel: UILabel!
  
  //Not particularly relevant this time
  override func viewDidLoad() {
    super.viewDidLoad()
  }

  //Long Press Gesture Recognizer installed on the storyboard (see the bottom of this article for details)
  @IBAction func longPressTap(_ sender: UILongPressGestureRecognizer) {
    
    //When you start tapping
    if sender.state == .began{
    
    //When you finish tapping
    } else if sender.state == .ended {
          
      //Get the latitude and longitude of MKMapView by specifying the tapped position (CGPoint)
      let tapPoint = sender.location(in: view)
      let center = mapView.convert(tapPoint, toCoordinateFrom: mapView)
      
      //latitude
      let lat = center.latitude
      
      //longitude
      let log = center.longitude
    
      //Pass arguments to the method that converts latitude / longitude to address
      convert(lat: lat, log: log)
    }
  }

  //Methods for converting latitude and longitude
  //The properties written around here may be easier to understand by looking at the link at the bottom of this article
  func convert(lat:CLLocationDegrees, log:CLLocationDegrees) {

    //Convert from address to latitude / longitude
    let geocoder = CLGeocoder()
    //Create an address from latitude and longitude
    let location = CLLocation(latitude: lat, longitude: log)
    
    //Closure (In principle, write things inside the closure with self. The inside of the parentheses is called after the value is entered, and the outside of the parentheses is called until the value is entered)
    //Get an address by reverse geocoding from longitude and latitude
    geocoder.reverseGeocodeLocation(location) {
      (placeMark, error) in
      
      //If you can get the address you expected
      if let placeMark = placeMark {
        if let pm = placeMark.first {

          //If you cannot get the address you expected, combine the character strings to create it.
          if pm.administrativeArea != nil || pm.locality != nil {
            self.addressString = pm.name! + pm.administrativeArea! + pm.locality!
          } else {
            self.addressString = pm.name!
          }
          //Show address in Labal
          self.addressLabel.text = self.addressString
        }
      }
    }
  }
}

Annotations and references

Long Press Gesture Recognizer

1. Place it on top of Map Kit View on the storyboard
2. Hold down the control key and drag and drop the icon created on the top bar (?) Of the view controller on the storyboard onto View Controller.swift to connect it.
3. Set ** Type ** to ** UILongPressGestureRecognizer ** as shown in the image below and press Connect

About properties and values ​​inside

reference

** I thought that the value that can be taken with the CLPlaceMark name changed in iOS 11, and verified it, and found that it was a strange property ** https://qiita.com/fr0g_fr0g/items/356d88ec906f2004f5f6

It's like this. With a vague understanding, it feels like a bit of a messy code.