Custom filtering logic

lib/location_cache.dart

@@ -0,0 +1,51 @@
+import 'package:flutter_background_geolocation/flutter_background_geolocation.dart' as bg;
+import 'package:traccar_client/preferences.dart';
+
+class Location {
+  final String timestamp;
+  final double latitude;
+  final double longitude;
+  final double heading;
+  const Location({
+    required this.timestamp,
+    required this.latitude,
+    required this.longitude,
+    required this.heading,
+  });
+}
+
+class LocationCache {
+  static Location? _last;
+
+  static Location? get() {
+    if (_last == null) {
+      final timestamp = Preferences.instance.getString(Preferences.lastTimestamp);
+      final latitude = Preferences.instance.getDouble(Preferences.lastLatitude);
+      final longitude = Preferences.instance.getDouble(Preferences.lastLongitude);
+      final heading = Preferences.instance.getDouble(Preferences.lastHeading);
+      if (timestamp != null && latitude != null && longitude != null && heading != null) {
+        _last = Location(
+          timestamp: timestamp,
+          latitude: latitude,
+          longitude: longitude,
+          heading: heading,
+        );
+      }
+    }
+    return _last;
+  }
+
+  static Future<void> set(bg.Location location) async {
+    final last = Location(
+      timestamp: location.timestamp,
+      latitude: location.coords.latitude,
+      longitude: location.coords.longitude,
+      heading: location.coords.heading,
+    );
+    Preferences.instance.setString(Preferences.lastTimestamp, last.timestamp);
+    Preferences.instance.setDouble(Preferences.lastLatitude, last.latitude);
+    Preferences.instance.setDouble(Preferences.lastLongitude, last.longitude);
+    Preferences.instance.setDouble(Preferences.lastHeading, last.heading);
+    _last = last;
+  }
+}