Firebaseからのデータの取得とマップへの注釈としての保存

Question

View Controllerで作成したフォームからFirebaseデータベースにデータを格納することに成功しましたが、マップ上に注釈として表示するデータを取得する必要があります。 2番目のビューコントローラですが、オンラインで何も検索せずに見つけた後、この作業をどうやってやるべきか分かりません。ここで

はFirebaseデータベースに正常に私のデータを保存し、私の作業コードです：

import UIKit 
import CoreLocation 
import Firebase 

class AddSightingViewController: UIViewController { 

    @IBOutlet weak var dateLabel: UILabel! 
    @IBOutlet weak var timeLabel: UILabel! 
    @IBOutlet weak var latitudeLabel: UILabel! 
    @IBOutlet weak var longitudeLabel: UILabel! 
    @IBOutlet weak var descriptionLabel: UITextView! 

    var locManager = CLLocationManager() 
    var currentLocation: CLLocation! 

    override func viewDidLoad() { 
     super.viewDidLoad() 

     // Set Date & Time 

     let dateFormatter = DateFormatter() 
     dateFormatter.dateStyle = .medium 

     dateFormatter.setLocalizedDateFormatFromTemplate("EEEE, MMM d, yyyy") // // set template after setting locale 

     let dateString = "\(dateFormatter.string(from: Date() as Date))" 
     dateLabel.text = String(dateString) 

     let timeFormatter = DateFormatter() 
     timeFormatter.timeStyle = .medium 

     timeFormatter.setLocalizedDateFormatFromTemplate("hhmm") 

     let timeString = "\(timeFormatter.string(from: Date() as Date))" 

     timeLabel.text = String(timeString) 

     // Set Latitude & Longitude 

     locManager.requestWhenInUseAuthorization() 

     if (CLLocationManager.authorizationStatus() == CLAuthorizationStatus.authorizedWhenInUse || 
      CLLocationManager.authorizationStatus() == CLAuthorizationStatus.authorizedAlways){ 
      currentLocation = locManager.location 
      self.latitudeLabel.text = String("\(currentLocation.coordinate.latitude)") 
      self.longitudeLabel.text = String("\(currentLocation.coordinate.longitude)") 
     } 
    } 

    func post() { 

     let date = dateLabel.text 
     let time = timeLabel.text 
     let latitude = latitudeLabel.text 
     let longitude = longitudeLabel.text 
     let sightingDescription = descriptionLabel.text 

     let post: [String : AnyObject] = ["Date" : date as AnyObject, 
              "Time" : time as AnyObject, 
              "Latitude" : latitude as AnyObject, 
              "Longitude" : longitude as AnyObject, 
              "Description" : sightingDescription as AnyObject] 

     var ref: DatabaseReference! 
     ref = Database.database().reference() 
     ref.child("Sightings").childByAutoId().setValue(post) 

    } 

    @IBAction func saveButton(_ sender: Any) { 

     post() 

     // Create the alert controller 
     let alertController = UIAlertController(title: "Sighting Logged Successfully", message: "Your logged entry will now show up on the map for others to see. Thank You!", preferredStyle: .alert) 

     // Create the actions 
     let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default) { 
      UIAlertAction in 
      NSLog("OK Pressed") 

     } 

     // Add the actions 
     alertController.addAction(okAction) 

     // Present the controller 
     self.present(alertController, animated: true, completion: nil) 

    } 

} 

Answer 1

この上で働いた後、私は最終的には、以下の機能を使用してのviewDidLoad（でそれを呼び出すことによって動作するようになってきました）

func displayAnnotations() { 

     let ref = Database.database().reference() 
     ref.child("Sightings").observe(.childAdded, with: { (snapshot) in 

      let date = (snapshot.value as AnyObject!)!["Date"] as! String! 
      let time = (snapshot.value as AnyObject!)!["Time"] as! String! 
      let latitude = (snapshot.value as AnyObject!)!["Latitude"] as! String! 
      let longitude = (snapshot.value as AnyObject!)!["Longitude"] as! String! 
      let desc = (snapshot.value as AnyObject!)!["Description"] as! String! 

      let annotation = MKPointAnnotation() 

      annotation.coordinate = CLLocationCoordinate2D(latitude: (Double(latitude!))!, longitude: (Double(longitude!))!) 
      annotation.title = date 
      annotation.subtitle = time 
      self.map.addAnnotation(annotation) 

     })}