GeofenceEvent class

Event-object provided to BackgroundGeolocation.onGeofence.

Example

BackgroundGeolocation.onGeofence((GeofenceEvent event) {
  print('[geofence] ${event.identifier}, ${event.action}');
});

Geofencing Guide

The Background Geolocation SDK implements the native iOS and Android Geofencing APIs.

ℹ️ Note:

  • Native iOS & Android API support only circular geofences, however the plugin does implement a custom mechanism for handling Polygon Geofences; see Geofence.vertices.
  • The minimum reliable Geofence.radius is 200 meters.
  • The native geofencing API for both iOS and Android require the user authorize Config.locationAuthorizationRequest Always — When in Use will not work.

Adding Geofences

Adding a single geofence with BackgroundGeolocation.addGeofence.

Example

BackgroundGeolocation.addGeofence(Geofence(
  identifier: "Home",
  radius: 200,
  latitude: 45.51921926,
  longitude: -73.61678581,
  notifyOnEntry: true,
  notifyOnExit: true,
  extras: {
    "route_id": 1234
  }
)).then((bool success) {
  print('[addGeofence] success');
}).catchError((dynamic error) {
  print('[addGeofence] FAILURE: $error');
});

Adding multiple geofences with BackgroundGeolocation.addGeofences.

Example

await BackgroundGeolocation.addGeofences([Geofence(
  identifier: "Home",
  radius: 200,
  latitude: 45.51921926,
  longitude: -73.61678581,
  notifyOnEntry: true,
), Geofence(
  identifier: "Work",
  radius: 200,
  latitude: 45.61921927,
  longitude: -73.71678582,
  notifyOnEntry: true
)]);
print('[addGeofences] success');

ℹ️ Note: Adding a geofence having an Geofence.identifier which already exists within the SDK's geofence database will cause the previous record to be destroyed and the new one inserted.

Listening for Geofence Events

Listen to geofence events with BackgroundGeolocation.onGeofence.

Example

// Listen for geofence events.
BackgroundGeolocation.onGeofence((GeofenceEvent event) {
  print('[geofence] ${event.identifier}, ${event.action}');
});

Polygon Geofencing

The Background Geolocation SDK supports Polygon Geofences (Geofences of any shape). See API docs Geofence.vertices. ℹ️ Polygon Geofencing is sold as a separate add-on (fully functional in DEBUG builds).

Infinite Geofencing

The Background Geolocation SDK contains unique and powerful Geofencing features that allow you to monitor any number of circular geofences you wish (thousands even), in spite of limits imposed by the native platform APIs (20 for iOS; 100 for Android).

The SDK achieves this by storing your geofences in its database, using a geospatial query to determine those geofences in proximity (Config.geofenceProximityRadius), activating only those geofences closest to the device's current location (according the limit imposed by the corresponding platform).

Listening for changes in the actively-monitored set-of-geofences.

As the SDK periodically queries for geofences within the Config.geofenceProximityRadius, you can listen for changes in the actively-monitored geofences using the event BackgroundGeolocation.onGeofencesChange. This event will let you know those geofences which have begun to be actively monitored (GeofencesChangeEvent.on) in addition to those which just ceased to be actively monitored (GeofencesChangeEvent.off).

Example

BackgroundGeolocation.onGeofencesChange((GeofencesChangeEvent event) {
  // Create map circles
  event.on.forEach((Geofence geofence) {
    createGeofenceMarker(geofence)
  });

  // Remove map circles
  event.off.forEach((String identifier) {
    removeGeofenceMarker(identifier);
  });
});

⚠️ Note:

Removing Geofences

Once a geofence has been inserted into the SDK's database using BackgroundGeolocation.addGeofence or BackgroundGeolocation.addGeofences, they will be monitored forever (as long as the plugin remains State.enabled == true). If you've configured Config.stopOnTerminate false and Config.startOnBoot true, geofences will continue to be monitored even if the application is terminated or device rebooted. To cease monitoring a geofence or geofences, you must remove them from the SDK's database (or call BackgroundGeolocation.stop).

Removing a single geofence by Geofence.identifier:

BackgroundGeolocation.removeGeofence('HOME').then((bool success) {
  print('[removeGeofence] success');
});

Removing all geofences with BackgroundGeolocation.removeGeofences:

BackgroundGeolocation.removeGeofences().then((bool success) {
  print('[removeGeofences] all geofences have been destroyed');
});

Querying Geofences

Use the method BackgroundGeolocation.geofences property to retrieve the entire Array of Geofence stored in the SDK's database:

List<Geofence> geofences = await BackgroundGeolocation.geofences;
print('[getGeofences: $geofences');

Or fetch a single geofence by Geofence.identifier with BackgroundGeolocation.getGeofence :

Geofence geofence = await BackgroundGeolocation.getGeofence("home");
print('[getGeofence] $geofence');

Monitoring only geofences

The BackgroundGeolocation SDK allows you to optionally monitor only geofences without constant location-tracking. To engage geofences-only mode, use the method BackgroundGeolocation.startGeofences instead of BackgroundGeolocation.start.

Use option Config.geofenceModeHighAccuracy:true to improve the responsiveness of geofence events.

BackgroundGeolocation.onGeofence((GeofenceEvent event) {
  print('[geofence]: ' + event.toString());
});

BackgroundGeolocation.ready(Config(
  url: 'http://your.server.com/geofences',
  autoSync: true,
  geofenceModeHighAccuracy: true   // <-- consumes more power; default is false.
)).then((State state) {
  // engage geofences-only mode:
  BackgroundGeolocation.startGeofences();
});

Toggling between tracking-modes BackgroundGeolocation.start and BackgroundGeolocation.startGeofences:

The SDK can easily be toggled between State.trackingMode simply by executing the corresponding BackgroundGeolocation.start or BackgroundGeolocation.startGeofences methods.

// Listen to geofence events
BackgroundGeolocation.onGeofence((GeofenceEvent event) {
  print('[geofence] ' + event.toString());
  if (event.identifier == 'DANGER_ZONE') {
    if (event.action == 'ENTER') {
      // Entering the danger-zone, we want to aggressively track location.
      BackgroundGeolocation.start();
    } else if (event.action == 'EXIT') {
      // Exiting the danger-zone, we resume geofences-only tracking.
      BackgroundGeolocation.startGeofences();
    }
  }
});

// Add a geofence.
BackgroundGeolocation.addGeofence(Geofence(
  identifier: "DANGER_ZONE",
  radius: 1000,
  latitude: 45.51921926,
  longitude: -73.61678581,
  notifyOnEntry: true,
  notifyOnExit: true,
));

// Ready the plugin.
BackgroundGeolocation.ready(Config(
  desiredAccuracy: BackgroundGeolocation.DESIRED_ACCURACY_HIGH,
  distanceFilter: 10,
  url: 'http://your.server.com/locations',
  autoSync: true
)).then((State state) {
  BackgroundGeolocation.startGeofences();
});

Constructors

GeofenceEvent(Map params)

Properties

action ↔ String
The transition event that caused the geofence to fire (ENTER | EXIT | DWELL).
getter/setter pair
extras ↔ Map?
Optional Geofence.extras
getter/setter pair
hashCode → int
The hash code for this object.
no setterinherited
identifier ↔ String
Geofence.identifier of the Geofence which fired.
getter/setter pair
location ↔ Location
The Location where this geofence triggered.
getter/setter pair
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
timestamp ↔ String
The device system time when the Geofence event was received by the OS. Note: this can differ from the timestamp of the triggering location responsible for the geofence (the triggering location can be from the past).
getter/setter pair

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
String representation of GeofenceEvent for print to logs.
override

Operators

operator ==(Object other) → bool
The equality operator.
inherited