maui-linux/Xamarin.Forms.Maps.GTK/GeocoderBackend.cs

using GMap.NET;
using GMap.NET.MapProviders;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Xamarin.Forms.Maps.GTK
{
    internal class GeocoderBackend
    {
        public static void Register()
        {
            Geocoder.GetPositionsForAddressAsyncFunc = GetPositionsForAddressAsync;
            Geocoder.GetAddressesForPositionFuncAsync = GetAddressesForPositionAsync;
        }

        public static Task<IEnumerable<Position>> GetPositionsForAddressAsync(string address)
        {
            var points = new List<PointLatLng>();
            var positions = new List<Position>();
            GMapProviders.GoogleMap.GetPoints(address, out points);

            if (points != null && points.Any())
            {
                foreach (var point in points)
                {
                    positions.Add(new Position(point.Lat, point.Lng));
                }
            }

            return Task.FromResult<IEnumerable<Position>>(positions);
        }

        public static Task<IEnumerable<string>> GetAddressesForPositionAsync(Position position)
        {
            var point = new PointLatLng(position.Latitude, position.Longitude);
            var direction = new GDirections();
            var addresses = new List<string>();
            GMapProviders.GoogleMap.GetDirections(out direction, point, point, false, true, false, false, true);

            if (!string.IsNullOrEmpty(direction.StartAddress))
            {
                addresses.Add(direction.StartAddress);
            }
            
            return Task.FromResult<IEnumerable<string>>(addresses);
        }
    }
}