Initial Android cadastral map app

Services/PreciseLocationService.cs

@@ -0,0 +1,96 @@
+using Microsoft.Maui.ApplicationModel;
+using Microsoft.Maui.Devices.Sensors;
+
+namespace LMEMappeCatastaliApp.Services;
+
+public sealed class PreciseLocationService : IAsyncDisposable
+{
+    private CancellationTokenSource? trackingCancellation;
+
+    public bool IsTracking => trackingCancellation is not null;
+
+    public async Task<PermissionStatus> EnsurePermissionAsync()
+    {
+        var status = await Permissions.CheckStatusAsync<Permissions.LocationWhenInUse>();
+        if (status != PermissionStatus.Granted)
+        {
+            status = await Permissions.RequestAsync<Permissions.LocationWhenInUse>();
+        }
+
+        return status;
+    }
+
+    public async Task StartTrackingAsync(Func<LocationSnapshot, Task> onLocation, Func<string, Task> onError)
+    {
+        if (trackingCancellation is not null)
+        {
+            return;
+        }
+
+        var permission = await EnsurePermissionAsync();
+        if (permission != PermissionStatus.Granted)
+        {
+            await onError("Permesso GPS non concesso.");
+            return;
+        }
+
+        trackingCancellation = new CancellationTokenSource();
+        var token = trackingCancellation.Token;
+
+        _ = Task.Run(async () =>
+        {
+            while (!token.IsCancellationRequested)
+            {
+                try
+                {
+                    var request = new GeolocationRequest(GeolocationAccuracy.Best, TimeSpan.FromSeconds(5));
+                    var location = await Geolocation.Default.GetLocationAsync(request, token);
+                    if (location is not null)
+                    {
+                        await onLocation(new LocationSnapshot(
+                            location.Latitude,
+                            location.Longitude,
+                            location.Accuracy,
+                            location.Altitude,
+                            location.Course,
+                            location.Speed,
+                            location.Timestamp));
+                    }
+                }
+                catch (OperationCanceledException)
+                {
+                    break;
+                }
+                catch (Exception ex)
+                {
+                    await onError(ex.Message);
+                    await Task.Delay(TimeSpan.FromSeconds(2), token);
+                }
+
+                await Task.Delay(TimeSpan.FromSeconds(1), token);
+            }
+        }, token);
+    }
+
+    public void StopTracking()
+    {
+        trackingCancellation?.Cancel();
+        trackingCancellation?.Dispose();
+        trackingCancellation = null;
+    }
+
+    public ValueTask DisposeAsync()
+    {
+        StopTracking();
+        return ValueTask.CompletedTask;
+    }
+}
+
+public sealed record LocationSnapshot(
+    double Latitude,
+    double Longitude,
+    double? Accuracy,
+    double? Altitude,
+    double? Course,
+    double? Speed,
+    DateTimeOffset Timestamp);