How to Add Geofencing Features to Your FlutterFlow App

1// Custom Action: startGeofenceMonitoring
2// Return type: void
3// Packages: geolocator, flutter_local_notifications, cloud_firestore
4
5import 'dart:math';
6
7Future<void> startGeofenceMonitoring() async {
8  // 1. Initialize local notifications
9  final flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();
10  const initSettings = InitializationSettings(
11    android: AndroidInitializationSettings('@mipmap/ic_launcher'),
12    iOS: DarwinInitializationSettings(),
13  );
14  await flutterLocalNotificationsPlugin.initialize(initSettings);
15
16  // 2. Request permission (Android 13+)
17  await flutterLocalNotificationsPlugin
18      .resolvePlatformSpecificImplementation<
19          AndroidFlutterLocalNotificationsPlugin>()
20      ?.requestNotificationsPermission();
21
22  // 3. Load active geofences from Firestore
23  final geofencesSnap = await FirebaseFirestore.instance
24      .collection('geofences')
25      .where('active', '==', true)
26      .get();
27
28  final geofences = geofencesSnap.docs.map((doc) {
29    final d = doc.data();
30    return {
31      'id': doc.id,
32      'name': d['name'] as String,
33      'lat': (d['centerLat'] as num).toDouble(),
34      'lng': (d['centerLng'] as num).toDouble(),
35      'radius': (d['radiusMeters'] as num).toDouble(),
36    };
37  }).toList();
38
39  // 4. Track which zones the user is currently inside
40  final Set<String> insideZones = {};
41
42  // 5. Start continuous position stream
43  final locationSettings = LocationSettings(
44    accuracy: LocationAccuracy.high,
45    distanceFilter: 20, // Only fire callback when user moves 20+ meters
46  );
47
48  Geolocator.getPositionStream(locationSettings: locationSettings)
49      .listen((Position position) async {
50    for (final geofence in geofences) {
51      final distance = _haversineMeters(
52        position.latitude, position.longitude,
53        geofence['lat'] as double, geofence['lng'] as double,
54      );
55      final isInside = distance <= (geofence['radius'] as double);
56      final wasInside = insideZones.contains(geofence['id']);
57
58      if (isInside && !wasInside) {
59        insideZones.add(geofence['id'] as String);
60        await _onGeofenceEvent(
61          flutterLocalNotificationsPlugin,
62          geofence['id'] as String,
63          geofence['name'] as String,
64          'entered',
65        );
66      } else if (!isInside && wasInside) {
67        insideZones.remove(geofence['id']);
68        await _onGeofenceEvent(
69          flutterLocalNotificationsPlugin,
70          geofence['id'] as String,
71          geofence['name'] as String,
72          'exited',
73        );
74      }
75    }
76  });
77}
78
79double _haversineMeters(double lat1, double lng1, double lat2, double lng2) {
80  const R = 6371000.0;
81  final dLat = (lat2 - lat1) * pi / 180;
82  final dLng = (lng2 - lng1) * pi / 180;
83  final a = sin(dLat / 2) * sin(dLat / 2) +
84      cos(lat1 * pi / 180) * cos(lat2 * pi / 180) *
85      sin(dLng / 2) * sin(dLng / 2);
86  return R * 2 * atan2(sqrt(a), sqrt(1 - a));
87}
88
89Future<void> _onGeofenceEvent(
90  FlutterLocalNotificationsPlugin plugin,
91  String zoneId,
92  String zoneName,
93  String eventType,
94) async {
95  // Show local notification
96  await plugin.show(
97    zoneId.hashCode,
98    eventType == 'entered' ? 'You arrived at $zoneName' : 'You left $zoneName',
99    eventType == 'entered'
100        ? 'Welcome to $zoneName!'
101        : 'You have exited $zoneName.',
102    const NotificationDetails(
103      android: AndroidNotificationDetails(
104        'geofence_channel',
105        'Geofence Alerts',
106        importance: Importance.high,
107        priority: Priority.high,
108      ),
109      iOS: DarwinNotificationDetails(),
110    ),
111  );
112
113  // Log event to Firestore
114  final uid = FirebaseAuth.instance.currentUser?.uid;
115  if (uid != null) {
116    await FirebaseFirestore.instance.collection('geofence_events').add({
117      'userId': uid,
118      'zoneId': zoneId,
119      'zoneName': zoneName,
120      'event': eventType,
121      'timestamp': FieldValue.serverTimestamp(),
122    });
123  }
124}

1// Custom Action: requestBackgroundLocation
2// Return type: String (permission status)
3
4Future<String> requestBackgroundLocation() async {
5  LocationPermission permission = await Geolocator.checkPermission();
6
7  if (permission == LocationPermission.denied) {
8    permission = await Geolocator.requestPermission();
9    if (permission == LocationPermission.denied) {
10      return 'denied';
11    }
12  }
13
14  if (permission == LocationPermission.deniedForever) {
15    // Direct user to app settings
16    await Geolocator.openAppSettings();
17    return 'deniedForever';
18  }
19
20  if (permission == LocationPermission.whileInUse) {
21    // On iOS, request upgrade to Always
22    permission = await Geolocator.requestPermission();
23  }
24
25  if (permission == LocationPermission.always) {
26    return 'always';
27  }
28
29  return 'whileInUse';
30}