Map Markers - Markers not appearing

App Development
1

Hi Chris, please can you help me again with this, its driving me crazy, the markers are not appearing on the map. The array is been populated.

Thanks Geoff

//
// ContentView.swift
// South Africa 24-02-2024
//
// Created by Geoff on 24/02/2024.
// Edited 26-02-2024
// Edited 26-02-2024
// Edited 06-03-2024

import SwiftUI
import MapKit

struct ContentView: View {
@State var tags: [String] =
@State var lats: [Double] =
@State var lons: [Double] = 

@State var latCount:  Int  = 0
@State var longCount: Int  = 0
@State var tagCount:  Int  = 0

@State var camera: MapCameraPosition = .automatic // change map view here

struct LandMark{  //Previously called MapMarker
    var latitude:  Double
    var longitude: Double
    var tag:       String
               }

@State var mapMarkers = [LandMark]() // Create an array
@State var mytext:      String =   "Working on it"
@State var inbody:      String =   "Now in body"
@State var inOnappear:  String =   "In //onappear"
@State var myText:      String =   "Working"
@State var inpopMarkers: String =  "Now in populate markers"
@State var myBlue:      String  =  "Blue Train"

var body: some View {
    Map()
    VStack{
        Text(inbody)
            .onAppear() 
            { populateMapMarkers()
              printCounters()
                print ("inOnappear")
                //mapMarkers.count
            }
    }
}

func populateMapMarkers() {  //populate the markers array
    print ("inpopMarkers")
    
    mapMarkers.append(LandMark(latitude: -25.757947887867694,
                               longitude: 28.189196654067267,
                               tag: "bluetrain"))
       
    mapMarkers.append(LandMark(latitude: -17.82536423477478,
                               longitude: 25.81926011162876, 
                               tag: "livAir")) // liv air
    
    mapMarkers.append(LandMark(latitude: -25.757947887867694,
                               longitude: 28.189196654067267,
                               tag: "bluetrain"))
    
    mapMarkers.append(LandMark(latitude: -17.82536423477478, //liv air
                               longitude: 25.81926011162876,
                               tag: "livAir"))

    mapMarkers.append(LandMark(latitude: -26.13305962090586, //jo air
                               longitude: 28.23189168563858,
                               tag: "jo_air"))

    mapMarkers.append(LandMark(latitude: -33.971204942427406, //cap_air
                               longitude: 18.598276359810573,
                               tag: "cap_air"))
            
    mapMarkers.append(LandMark(latitude: -26.14440600932509, // Peer
                               longitude: 28.22131032404206,
                               tag: "// Peer"))

    mapMarkers.append(LandMark(latitude: -17.864082081117978, // lvingstone train
                               longitude: 25.854742557680495,
                               tag: "// Liv Train"))

    mapMarkers.append(LandMark(latitude: -17.925316439275523, // vic falls
                               longitude: 25.858513402639517,
                               tag: "// V_Falls"))
    
    mapMarkers.append(LandMark(latitude: -25.185360010673655, // //ivy lodge
                               longitude: 27.1470279923556,
                               tag: "Ivy"))
    
    mapMarkers.append(LandMark(latitude: -25.24023368183164, // Pilan
                               longitude: 27.0759065323271,
                               tag: "// Pilan"))
    
    print("List of array entries below ")
    print("Array: \(mapMarkers)")
    // Add the remainder of the markers in a similar fashion
   }
//var result2 = mapMarkers.count
    //  Print statements

func printCounters()
{
    print (mapMarkers.count)
    //print("tagCount:  \(tagCount)")
}

    }

#Preview {
ContentView()
}

2

@wonkydonky

Hi Geoff,

Sorry mate, I meant to get back to you on the other thread but have since got sidetracked on other stuff. I think I am burning the candle at both ends.

I played around with getting the MapMarkers to appear on a Map and ended up changing the struct that forms the template for the markers.

Have a look at this code and see if you can understand what I have done.

import SwiftUI
import MapKit

struct MapLocation: Identifiable {
    var id = UUID()
    var name: String
    var coordinate: CLLocationCoordinate2D
}

struct ContentView1: View {

    @State var mytext: String = "Working on it"

    @State var camera: MapCameraPosition = .automatic

    @State var mapMarkers = [MapLocation]()
    @State var region = MKCoordinateRegion(center: CLLocationCoordinate2D(latitude: -25.24023368183164, longitude: 27.0759065323271), span: MKCoordinateSpan(latitudeDelta: 10, longitudeDelta: 10))


    var body: some View {
        VStack{
            Text(mytext)
            Map(initialPosition: camera) {
                ForEach(mapMarkers) { marker in
                    Marker(marker.name, coordinate: marker.coordinate)
                }

            }
        }
        .onAppear() {
            populateMapMarkers()
        }
    }

    func populateMapMarkers() {
        mapMarkers.append(MapLocation(name: "bluetrain", coordinate: CLLocationCoordinate2D(latitude: -25.757947887867694, longitude: 28.189196654067267))) // Blue Train
        mapMarkers.append(MapLocation(name: "livAir", coordinate: CLLocationCoordinate2D(latitude: -17.82536423477478, longitude: 25.81926011162876))) // liv air
        mapMarkers.append(MapLocation(name: "jo_air", coordinate: CLLocationCoordinate2D(latitude: -26.13305962090586, longitude: 28.23189168563858))) // jo_air
        mapMarkers.append(MapLocation(name: "cap_air", coordinate: CLLocationCoordinate2D(latitude: -33.971204942427406, longitude: 18.598276359810573))) // cap_air
        mapMarkers.append(MapLocation(name: "Peer", coordinate: CLLocationCoordinate2D(latitude: -26.14440600932509, longitude: 28.22131032404206))) // Peer
        mapMarkers.append(MapLocation(name: "Liv Train", coordinate: CLLocationCoordinate2D(latitude: -17.864082081117978, longitude: 25.854742557680495))) //lvingstone train
        mapMarkers.append(MapLocation(name: "V_Falls", coordinate: CLLocationCoordinate2D(latitude: -17.925316439275523, longitude: 25.858513402639517))) // vic falls
        mapMarkers.append(MapLocation(name: "Ivy", coordinate: CLLocationCoordinate2D(latitude: -25.185360010673655, longitude: 27.1470279923556))) //ivy lodge
        mapMarkers.append(MapLocation(name: "Pilan", coordinate: CLLocationCoordinate2D( latitude: -25.24023368183164, longitude: 27.0759065323271))) //Pilan

        print("mapMarkers count: \(mapMarkers.count)")
    }
}

#Preview {
    ContentView1()
}
3

Thank you so much for doing this for me, it’s appreciated.

When I copy the code into Xcode I get the message saying 'Failed to build the scheme’ full report below - cannot find ‘ContentView’ in scope.

Please can you offer guidance?

I can see how you are creating many instances of mapMakers and giving them their own unique identity.

Also, you have added some useful features.

Many thanks, again

4

WOW, WOW, WOW!!! I just changed ContentView1 to ContentView, and everything sprung into life.

5

Pretty cool huh?