How to clustered markers from Firebase in GoogleMaps for iOS

Question

I\'m developing an app on which I want to show a lot of events on the map. The user can click on an event and see a lot of informations about it. In another view, a user can

Answer 1

I resolve my question so I post here the solution, thank to Prateek for his help.

I use this topic for solve it too : How to implement GMUClusterRenderer in Swift

First I changed one line of code in a GoogleMaps files SDK: I found it in my project at this path : Pods/Pods/Google-Maps-iOS-Utils/Clustering/GMUDefaultClusterRenderer.m This file name is GMUDefaultClusterRenderer.m. This changement it's for cluster custom marker icon in the cluster

- (void)renderCluster:(id<GMUCluster>)cluster animated:(BOOL)animated {
...

  GMSMarker *marker = [self markerWithPosition:item.position
                                          from:fromPosition
                                      userData:item
                                   clusterIcon:[UIImage imageNamed:@"YOUR_CUSTOM_ICON"] // Here you change "nil" by the name of your image icon
                                      animated:shouldAnimate];
  [_markers addObject:marker];
  [_renderedClusterItems addObject:item];
...
}

Second, I added this function in my Swift file of my map :

private func setupClusterManager() {
    let iconGenerator = GMUDefaultClusterIconGenerator()
    let algorithm = GMUNonHierarchicalDistanceBasedAlgorithm()
    let renderer = GMUDefaultClusterRenderer(mapView: maMap,
                                             clusterIconGenerator: iconGenerator)

    clusterManager = GMUClusterManager(map: maMap, algorithm: algorithm,
                                       renderer: renderer)

}

Third, I added a variable in the POIItem class in order to get information from Firebase, to show it in infoWindows of markers:

class POIItem: NSObject, GMUClusterItem {
var position: CLLocationCoordinate2D
var name: String!
var snippet: String! // I add it here

init(position: CLLocationCoordinate2D, name: String, snippet: String) {
    self.position = position
    self.name = name
    self.snippet = snippet // I add it also here
}
}

I get the informations of markers from Firebase thanks to POIItem class in the following function (before I call the function loadMarker() in order to load the data of each markers from Firebase):

func mapView(_ mapView: GMSMapView, didTap marker: GMSMarker) -> Bool {
    if let poiItem = marker.userData as? POIItem {
        NSLog("Did tap marker for cluster item \(poiItem.name!)")
        marker.title = "\(poiItem.name!)"
        marker.snippet = "\(poiItem.snippet!)"
        self.estTouche = true
        if self.estTouche == true {
           self.alert(self.estTouche as AnyObject) // If true it shows an alertController
        } else {
           print("estTouche est false")
        }
           print(self.estTouche)
    } else {
        NSLog("Did tap a normal marker")
    }
    return false
}

Here's the whole code of the solution, it works fine for me.

import UIKit
import GoogleMaps
import CoreLocation
import Firebase
import FirebaseAuth
import FirebaseDatabase

/// Point of Interest Item which implements the GMUClusterItem protocol.
class POIItem: NSObject, GMUClusterItem {
var position: CLLocationCoordinate2D
var name: String!
var snippet: String!

init(position: CLLocationCoordinate2D, name: String, snippet: String) {
    self.position = position
    self.name = name
    self.snippet = snippet
}
}

class NewCarteViewController: UIViewController, GMSMapViewDelegate, CLLocationManagerDelegate, GMUClusterManagerDelegate {

var locationManager = CLLocationManager()
var positionActuelle = CLLocation()
var positionEvent = CLLocationCoordinate2D()
var currentPosition = CLLocationCoordinate2D()
var latiti: CLLocationDegrees!
var longiti: CLLocationDegrees!

private var clusterManager: GMUClusterManager! // Cluster

private var maMap: GMSMapView!
var marker = GMSMarker()

var ref = DatabaseReference() // Firebase reference
var estTouche: Bool!
let geoCoder = CLGeocoder()

// For load the map
override func loadView() {
    let camera = GMSCameraPosition.camera(withLatitude: 48.898902,
                                      longitude: 2.282664, zoom: 12)
    maMap = GMSMapView.map(withFrame: CGRect.zero, camera: camera)
    self.view = maMap
}

override func viewDidLoad() {
    super.viewDidLoad()
    let iconGenerator = GMUDefaultClusterIconGenerator()
    let algorithm = GMUNonHierarchicalDistanceBasedAlgorithm() // crée un gestionnaire de groupes utilisant l'algorithme
    let renderer = GMUDefaultClusterRenderer(mapView: maMap, clusterIconGenerator: iconGenerator) // Le renderer est le moteur de rendu des groupes
    clusterManager = GMUClusterManager(map: maMap, algorithm: algorithm, renderer: renderer)

    loadMarker()

    locationManager.delegate = self
    locationManager.requestWhenInUseAuthorization()

    positionActuelle = locationManager.location!
    latiti = positionActuelle.coordinate.latitude
    longiti = positionActuelle.coordinate.longitude

    currentPosition = CLLocationCoordinate2D(latitude: latiti, longitude: longiti)

    maMap.mapType = .normal
    maMap.settings.compassButton = true // Boussole
    maMap.isMyLocationEnabled = true // User current position icon
    maMap.settings.myLocationButton = true // Button for center the camera on the user current position
    maMap.delegate = self
}

// Download datas of markers from Firebase Database
  func loadMarker() {
    ref = Database.database().reference()
    let usersRef = ref.child("markers")

    usersRef.observeSingleEvent(of: .value, with: { (snapshot) in
        if (snapshot.value is NSNull) {
            print("not found")
        } else {
            for child in snapshot.children {
                let userSnap = child as! DataSnapshot
                let uid = userSnap.key // The uid of each user
                let userDict = userSnap.value as! [String: AnyObject] // Child data
                let latitudes = userDict["latitudeEvent"] as! Double
                let longitudes = userDict["longitudeEvent"] as! Double
                let bellname = userDict["nom"] as! String
                let belltitre = userDict["titreEvent"] as! String
                let total = snapshot.childrenCount // Count of markers save in my Firebase database
                print("Total de marqueurs : \(total)")

                let positionMarker = CLLocationCoordinate2DMake(bellatitude, bellongitude)
                var diff = Double(round(100*self.getDistanceMetresBetweenLocationCoordinates(positionMarker, coord2: self.currentPosition))/100)
                var dif = Double(round(100*diff)/100)

                var positionEvenement = CLLocation(latitude: latitudes, longitude: longitudes)

                // Function in order to convert GPS Coordinate in an address
                CLGeocoder().reverseGeocodeLocation(positionEvenement, completionHandler: {(placemarks, error) -> Void in

                    if error != nil {
                        print("Reverse geocoder meets error " + (error?.localizedDescription)!)
                        return
                    }

                    if (placemarks?.count)! > 0 {
                        print("PlaceMarks \((placemarks?.count)!)")
                        let pm = placemarks?[0] as! CLPlacemark
                        var adres = "\(pm.name!), \(pm.postalCode!) \(pm.locality!)"
                        let item = POIItem(position: CLLocationCoordinate2DMake(latitudes, longitudes), name: "\(belltitre)", snippet: "Live de \(bellname)\nLieu: \(adres)\nDistance: \(dif) km") // This line is very important in order to import data from Firebase and show in infoWindow for the right datas for each markers
                        self.clusterManager.add(item)
                        self.clusterManager.cluster()
                        self.clusterManager.setDelegate(self, mapDelegate: self)
                    } else {
                        print("Problème avec les données reçues par le géocoder")
                    }
                })
            }
        }
    })
}

func mapView(_ mapView: GMSMapView, didTap marker: GMSMarker) -> Bool {
    if let poiItem = marker.userData as? POIItem {
        NSLog("Did tap marker for cluster item \(poiItem.name!)")
        marker.title = "\(poiItem.name!)" // Title of the marker infoWindow (title from Firebase)
        marker.snippet = "\(poiItem.snippet!)" // Same for snippet
        self.estTouche = true
        if self.estTouche == true {
           self.alert(self.estTouche as AnyObject) // Show the alertController because infoWindows can't use button
        } else {
           print("estTouche est false")
        }
           print(self.estTouche)
    } else {
        NSLog("Did tap a normal marker")
    }
    return false
}

// If I tap a cluster icon, it zoom in +1
func clusterManager(_ clusterManager: GMUClusterManager, didTap cluster: GMUCluster) -> Bool {
    let newCamera = GMSCameraPosition.camera(withTarget: cluster.position, zoom: maMap.camera.zoom + 1)
    let update = GMSCameraUpdate.setCamera(newCamera)
    maMap.moveCamera(update)
    return false
}

private func setupClusterManager() {
    let iconGenerator = GMUDefaultClusterIconGenerator()
    let algorithm = GMUNonHierarchicalDistanceBasedAlgorithm()
    let renderer = GMUDefaultClusterRenderer(mapView: maMap,
                                             clusterIconGenerator: iconGenerator)

    clusterManager = GMUClusterManager(map: maMap, algorithm: algorithm,
                                       renderer: renderer)

}

func renderer(_ renderer: GMUClusterRenderer, markerFor object: Any) -> GMSMarker? {
    if let model = object as? POIItem {
      self.clusterManager.cluster()
      self.clusterManager.setDelegate(self, mapDelegate: self)
    }
    return nil
}

// Distance between 2 locations
func getDistanceMetresBetweenLocationCoordinates(_ coord1: CLLocationCoordinate2D, coord2: CLLocationCoordinate2D) -> Double {
    let location1 = CLLocation(latitude: coord1.latitude, longitude: coord1.longitude)
    let location2 = CLLocation(latitude: coord2.latitude, longitude: coord2.longitude)
    var distance = ((location1.distance(from: location2)) / 1000)
    return distance
}

// Show alertController with 2 buttons and a Cancel button
func alert(_ sender: AnyObject) {
    let alertController = UIAlertController(title: "", message: "", preferredStyle: .actionSheet) // Ne me donne pas le bon nom
    alertController.title = nil
    alertController.message = nil // Supprime la ligne message sous le titre afin de pouvoir centrer le titre
    alertController.addAction(UIAlertAction(title: "Accéder au live", style: .default, handler: self.accederLive))
    alertController.addAction(UIAlertAction(title: "Infos event", style: .default, handler: self.infosEvent)) // Ou Affichage du profil utilisateur
    alertController.addAction(UIAlertAction(title: "Annuler", style: .cancel, handler: nil))
    self.present(alertController, animated: true, completion: nil)
}

// The two following functions are used in alertController
func accederLive(_ sender: AnyObject) {
...
}

func infosEvent(_ sender: AnyObject) {
    let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "Event")
    present(vc, animated: true, completion: nil)
}

func mapView(_ mapView: GMSMapView!, markerInfoWindow marker: GMSMarker!) -> UIView! {
    let infoWindow = Bundle.main.loadNibNamed("InfoWindow", owner: self, options: nil)?.first! as! CustomInfoWindow
    return nil
}
}

Hope it can help someone else.

I add finally my way to load the data of the marker in Firebase in another Swift file (if it can help someone to do it too) :

var locationManage = CLLocationManager()
var positionActuel = CLLocation() // Current position of user
var latitudinale: CLLocationDegrees! // Latitude
var longitudinale: CLLocationDegrees! // Longitude
var m = GMSMarker()

class AddEventViewController: UIViewController, UISearchBarDelegate, GMSMapViewDelegate, CLLocationManagerDelegate {

var categorie: String! // Type of event
var titre: String! // Title of event
var name: String! // Username

var userId = Auth.auth().currentUser?.uid // Get the uid of the connected user in Firebase

@IBOutlet weak var titreTextField: UITextField! // TextField in where user can set a title

override func viewDidLoad() {
    super.viewDidLoad()
...

    locationManage.delegate = self
    locationManage.requestWhenInUseAuthorization()

    positionActuel = locationManage.location!
    latitudinale = positionActuel.coordinate.latitude
    longitudinale = positionActuel.coordinate.longitude

    name = Auth.auth().currentUser?.displayName // In order to get the username of the connected user in Firebase
}

@IBAction func goAction(_ sender: Any) {
    let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "Live")
    self.present(vc, animated: true, completion: nil)

    if titreTextField.text == "" {
        titre = "\(name!) Live \(categorie!)"
    } else {
        titre = titreTextField.text!
    }

    setMarker(marker: m) // Add a marker on the map
}

// Save data of this event in Firebase (and this marker on Firebase)
func setMarker(marker: GMSMarker) {
    var lati = latitudinale
    var longi = longitudinale
    var nom = self.name
    var title = self.titre

    var userMarker = ["nom": nom!, // User name
        "latitudeEvent": lati!, // Latitude of event
        "longitudeEvent": longi!, // Longitude of event
        "titreEvent": title!] as [String : AnyObject] // Title of event

    KeychainWrapper.standard.set(userId!, forKey: "uid")

    let emplacement = Database.database().reference().child("markers").child(userId!) // Reference of my Firebase Database
    emplacement.setValue(userMarker)
}
}

Answer 2

Firstly loadMarker() should be called after the clusterManager is initialized i.e

clusterManager = GMUClusterManager(map: maMap, algorithm: algorithm, renderer: renderer)

then

clusterManager.cluster()
clusterManager.setDelegate(self, mapDelegate: self)

should be placed in loadMarker() after for loop ends.

Your viewcontroller should conform to this protocol GMUClusterManagerDelegate then add these 2 methods in viewcontroller.

func renderer(_ renderer: GMUClusterRenderer, markerFor object: Any) -> GMSMarker? {

    let marker = GMSMarker()
    if let model = object as? MarkerModel {
         // set image view for gmsmarker
    }

    return marker
}

func clusterManager(_ clusterManager: GMUClusterManager, didTap cluster: GMUCluster) -> Bool {
    let newCamera = GMSCameraPosition.camera(withTarget: cluster.position, zoom: mapView.camera.zoom + 1)
    let update = GMSCameraUpdate.setCamera(newCamera)
    mapView.moveCamera(update)
    return false
}

Try this and let me know if this works else we will try something else.