Hello
Ive been experimenting with xamarin form maps and followed the docuemntation and some tutorials on creating a custom renderer for Android.
I successfully got the custom pins example to work for the single pin example in for the San Francisco microsoft office.
However, i am loading a bunch of pins from a JSON file i took from an online example.
That all works and my custom icon is shown on the map.
When i click any pin however, i get a null exception for customPins.
I am not 100% sure what is wrong but all i really want to do with the pins is literally on click show a view that has a bit of text and an image.
Ive been debugging for a while now and just cant quite figure out why my multiple pins code doesnt work as intended. Below is my custom map renderer for Android.
using Android.Content;
using Android.Gms.Maps;
using Android.Gms.Maps.Model;
using Android.Widget;
using MAPS;
using MAPS.Droid;
using System;
using System.Collections.Generic;
using Xamarin.Forms;
using Xamarin.Forms.Maps;
using Xamarin.Forms.Maps.Android;
[assembly: ExportRenderer(typeof(CustomMap), typeof(CustomMapRenderer))]
namespace MAPS.Droid
{
public class CustomMapRenderer : Xamarin.Forms.Maps.Android.MapRenderer, GoogleMap.IInfoWindowAdapter
{
List<CustomPin> customPins;
public CustomMapRenderer(Context context) : base(context)
{
}
protected override void OnElementChanged(Xamarin.Forms.Platform.Android.ElementChangedEventArgs<Map> e)
{
base.OnElementChanged(e);
if (e.OldElement != null)
{
NativeMap.InfoWindowClick -= OnInfoWindowClick;
}
if (e.NewElement != null)
{
var formsMap = (CustomMap)e.NewElement;
customPins = formsMap.CustomPins;
}
}
protected override void OnMapReady(GoogleMap map)
{
base.OnMapReady(map);
NativeMap.InfoWindowClick += OnInfoWindowClick;
NativeMap.SetInfoWindowAdapter(this);
}
protected override MarkerOptions CreateMarker(Pin pin)
{
var marker = new MarkerOptions();
CustomPin p = new CustomPin();
foreach (var cp in customPins)
{
if (cp.Position == pin.Position)
{
p = cp;
}
}
marker.SetPosition(new LatLng(pin.Position.Latitude, pin.Position.Longitude));
marker.SetTitle(pin.Label);
// marker.SetSnippet(pin.Address);
// marker.SetIcon(BitmapDescriptorFactory.FromFile(p.icon));
marker.SetIcon(BitmapDescriptorFactory.FromResource(Resource.Drawable.pin));
return marker;
}
void OnInfoWindowClick(object sender, GoogleMap.InfoWindowClickEventArgs e)
{
var customPin = GetCustomPin(e.Marker);
if (customPin == null)
{
throw new Exception("Custom pin not found");
}
if (!string.IsNullOrWhiteSpace(customPin.Url))
{
var url = Android.Net.Uri.Parse(customPin.Url);
var intent = new Intent(Intent.ActionView, url);
intent.AddFlags(ActivityFlags.NewTask);
Android.App.Application.Context.StartActivity(intent);
}
}
//}
public Android.Views.View GetInfoContents(Marker marker)
{
var inflater = Android.App.Application.Context.GetSystemService(Context.LayoutInflaterService) as Android.Views.LayoutInflater;
if (inflater != null)
{
Android.Views.View view;
var customPin = GetCustomPin(marker);
if (customPin == null)
{
// throw new Exception("Custom pin not found");
}
if (customPin.Name.Equals("Xamarin"))
{
view = inflater.Inflate(Resource.Layout.XamarinMapInfoWindow, null);
}
else
{
view = inflater.Inflate(Resource.Layout.MapInfoWindow, null);
}
var infoTitle = view.FindViewById<TextView>(Resource.Id.InfoWindowTitle);
var infoSubtitle = view.FindViewById<TextView>(Resource.Id.InfoWindowSubtitle);
if (infoTitle != null)
{
infoTitle.Text = marker.Title;
}
if (infoSubtitle != null)
{
infoSubtitle.Text = marker.Snippet;
}
return view;
}
return null;
}
//public Android.Views.View GetInfoContents(Marker marker)
//{
// throw new NotImplementedException();
//}
public Android.Views.View GetInfoWindow(Marker marker)
{
return null;
}
CustomPin GetCustomPin(Marker annotation)
{
var position = new Position(annotation.Position.Latitude, annotation.Position.Longitude);
foreach (var pin in customPins)
{
if (pin.Position == position)
{
return pin;
}
}
return null;
}
}
}
And below is my aboutpage form, there are some background gps and other things in there that can be ignored.
using System;
using System.IO;
using System.Reflection;
using Xamarin.Forms;
using Newtonsoft.Json;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading.Tasks;
using Xamarin.Forms.Maps;
using Xamarin.Essentials;
using Distance = Xamarin.Forms.Maps.Distance;
using Google.Protobuf.WellKnownTypes;
using static Google.Protobuf.Reflection.FieldDescriptorProto.Types;
namespace MAPS.Views
{
public partial class AboutPage : ContentPage
{
IlocationUpdateService loc;
public AboutPage()
{
InitializeComponent();
Task.Delay(2000);
UpdateMap();
}
async void OnActionSheetCancelDeleteClicked()
{
bool answer = await DisplayAlert("Location Request", "Please enable location services to use this app", "Settings", "Cancel");
if (answer == true)
{
DependencyService.Get<ILocSettings>().OpenSettings();
}
}
protected override void OnAppearing()
{
base.OnAppearing();
bool gpsStat = DependencyService.Get<ILocSettings>().isGpsAvailable();
if (gpsStat == false)
{
OnActionSheetCancelDeleteClicked();
}
loc = DependencyService.Get<IlocationUpdateService>();
loc.LocationChanged += (object sender, ILocationEventArgs args) =>
{
String lat1 = args.Latitude.ToString();
String lng1 = args.Longitude.ToString();
// UpdateMap();
};
loc.GetUsedLocation();
}
protected override void OnDisappearing()
{
base.OnDisappearing();
loc = null;
}
List<Place> placesList = new List<Place>();
private async void UpdateMap()
{
var assembly = IntrospectionExtensions.GetTypeInfo(typeof(AboutPage)).Assembly;
Stream stream = assembly.GetManifestResourceStream("MAPS.Places.json");
string text = string.Empty;
using (var reader = new StreamReader(stream))
{
text = reader.ReadToEnd();
}
var resultObject = JsonConvert.DeserializeObject<Places>(text);
var request = new Xamarin.Essentials.GeolocationRequest(GeolocationAccuracy.Best, TimeSpan.FromSeconds(30));
var location = await Geolocation.GetLocationAsync(request);
CustomMap customMap = new CustomMap()
{
IsShowingUser = true
};
customMap.CustomPins = new List<CustomPin>(); // put this before the foreach
foreach (var place in resultObject.results)
{
CustomPin pin = new CustomPin()
{
Type = PinType.Place,
Position = new Position(place.geometry.location.lat, place.geometry.location.lng),
Label = place.name,
Address = place.vicinity,
Name = "Xamarin",
icon = "pin.png",
Url = "http://xamarin.com/about/"
};
customMap.Pins.Add(pin);
}
customMap.MoveToRegion(MapSpan.FromCenterAndRadius(new Position(location.Latitude, location.Longitude), Distance.FromKilometers(0.4))); ;
Content = customMap;
Thanks guys, much appreciated!