Thanks very much for your help. I have made little progress and am getting very frustrated.
I have got the code to the stage as shown below.
I cannot work out how to get the onAppear() to fire and populate the markers.
Please can you help me further?
Thanks, Geoff
//
// ContentView.swift
// Chris Solution
//
// Created by Geoff Smith on 28-01-2024
//
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 mytext: String = "Working on it"
@State var camera: MapCameraPosition = .automatic
var body: some View {
VStack{
Text(mytext)
.onAppear() {
populateMarkers()
}
}
}
func populateMarkers() {
lats.append(-25.757947887867694) //Blue Train
lons.append(28.189196654067267)
tags.append("bluetrain")
lats.append(-17.82536423477478) //liv air
lons.append(25.81926011162876)
tags.append("livAir")
lats.append(-26.13305962090586) //jo air
lons.append(28.23189168563858)
tags.append("jo_air")
lats.append(-33.971204942427406)//cap air
lons.append(18.598276359810573)
tags.append("cap_air")
lats.append(-26.14440600932509) // Peer
lons.append(28.22131032404206)
tags.append("Peer")
lats.append(-17.864082081117978) //lvingstone train
lons.append(25.854742557680495)
tags.append("Liv Train")
lats.append(-17.925316439275523)
lons.append(25.858513402639517) // vic falls
tags.append("V_Falls")
lats.append(-25.185360010673655)
lons.append(27.1470279923556) //ivy lodge
tags.append("Ivy")
lats.append(-25.24023368183164)
lons.append(27.0759065323271) //Pilan
tags.append("Pilan")
latCount = lats.count
longCount = lons.count
tagCount = tags.count
}
}
#Preview {
ContentView()
}
Your code is fine.
If you want to see it working when running it n the Preview canvas then all you need to do is add a few print statements at the end of the function to show that populateMarkers has been called and did populate the arrays. You will see that data being printed in the debug panel at the bottom of the Xcode window. If you can’t see that panel then use the keyboard short cut Shift + Command + C to make it visible.
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 mytext: String = "Working on it"
@State var camera: MapCameraPosition = .automatic
var body: some View {
VStack{
Text(mytext)
.onAppear() {
populateMarkers()
}
}
}
func populateMarkers() {
lats.append(-25.757947887867694) //Blue Train
lons.append(28.189196654067267)
tags.append("bluetrain")
lats.append(-17.82536423477478) //liv air
lons.append(25.81926011162876)
tags.append("livAir")
lats.append(-26.13305962090586) //jo air
lons.append(28.23189168563858)
tags.append("jo_air")
lats.append(-33.971204942427406)//cap air
lons.append(18.598276359810573)
tags.append("cap_air")
lats.append(-26.14440600932509) // Peer
lons.append(28.22131032404206)
tags.append("Peer")
lats.append(-17.864082081117978) //lvingstone train
lons.append(25.854742557680495)
tags.append("Liv Train")
lats.append(-17.925316439275523)
lons.append(25.858513402639517) // vic falls
tags.append("V_Falls")
lats.append(-25.185360010673655)
lons.append(27.1470279923556) //ivy lodge
tags.append("Ivy")
lats.append(-25.24023368183164)
lons.append(27.0759065323271) //Pilan
tags.append("Pilan")
latCount = lats.count
longCount = lons.count
tagCount = tags.count
// Print statements
print("latCount: \(latCount)")
print("longCount: \(longCount)")
print("tagCount: \(tagCount)")
}
}
You may recall that I suggested in a previous post (back in early January) that you create a struct to store each instance of a Map Marker. For example:
struct LandMark {
var latitude: Double
var longitude: Double
var tag: String
}
Note: I suggested naming the struct MapMarker which in hindsight could have clashed with an existing SwiftUI Map protocol so call it something else.
and then declare an array of mapMarkers like this:
@State var mapMarkers = [LandMark]()
and then have a function to populate those markers like this:
func populateMapMarkers() {
mapMarkers.append(LandMark(latitude: -25.757947887867694, longitude: 28.189196654067267, tag: "bluetrain")) // Blue Train
mapMarkers.append(LandMark(latitude: -17.82536423477478, longitude: 25.81926011162876, tag: "livAir")) // liv air
// Add the remainder of the markers in a similar fashion
}
and call that in your onAppear code:
.onAppear {
populateMapMarkers()
}
Thank you very much for your help and support - would not have got this far with out your help and assistance.
I think I have implemented all your advice. I have nob got other problems.
When I launch the app it worked and text messages appear in the simulator and on my device. The app does not advance to displaying the actual map.
Please can you help?
Code below.
// Created by Chris Ching on 2023-07-13.
import SwiftUI
import MapKit
struct MapMarker {
var latitude: Double
var longitude: Double
var tag: String
}
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 mytext: String = "Working on it"
@State var onap: String = "In on appear"
@State var camera: MapCameraPosition = .automatic
var body: some View {
VStack{
Text(onap)
.onAppear {
populateMapMarkers()
}
}
}
@State var mapMarkers = [MapMarker]() // Create an array of map Markers
func populateMapMarkers() {
mapMarkers.append(MapMarker(
latitude: -25.757947887867694,
longitude: 28.189196654067267,
tag: "bluetrain")) // Blue Train
mapMarkers.append(MapMarker(
latitude: -17.82536423477478,
longitude: 25.81926011162876,
tag: "livAir")) // liv air
// Add the remainder of the markers in a similar fashion
mapMarkers.append(MapMarker(
latitude: -26.13305962090586,
longitude: 28.23189168563858,
tag: "JoAir")) // JoAir
mapMarkers.append(MapMarker(
latitude: -33.971204942427406,
longitude: 18.598276359810573,
tag: "CapAir")) // CapAir
mapMarkers.append(MapMarker(
latitude: -26.14440600932509,
longitude: 8.22131032404206,
tag: "Peer")) // Peer
}
}
#Preview {
ContentView()
}