Class Geofence

java.lang.Object
com.codename1.location.Geofence
public class Geofence extends Object

Metadata for geofencing support that allows tracking user location in the background while the app is inactive.

The sample below tracks location and posts a notification or shows a dialog based on the state of the app:

// File: GeofenceListenerImpl.java
public class GeofenceListenerImpl implements GeofenceListener {
@Override
    public void onExit(String id) {
    }
@Override
    public void onEntered(String id) {
        if(!Display.getInstance().isMinimized()) {
            Display.getInstance().callSerially(() -> {
                Dialog.show("Welcome", "Thanks for arriving", "OK", null);
            });
        } else {
            LocalNotification ln = new LocalNotification();
            ln.setId("LnMessage");
            ln.setAlertTitle("Welcome");
            ln.setAlertBody("Thanks for arriving!");
            Display.getInstance().scheduleLocalNotification(ln, System.currentTimeMillis() + 10, LocalNotification.REPEAT_NONE);
        }
    }
}

// File: GeofenceSample.java
Geofence gf = new Geofence("test", loc, 100, 100000);
LocationManager.getLocationManager().addGeoFencing(GeofenceListenerImpl.class, gf);

NOTE: For iOS you must include the ios.background_modes build hint with a value that includes "location" for geofencing to work.

Geofencing is not supported on all platforms, use LocationManager#isGeofenceSupported() to find out if the current platform supports it at runtime.

The maximum number of simulataneous Geofences allowed will vary by platform. iOS currently has a maximum of 20, and Android has a maximum of 100. If you need to track more than 20 at a time, consider using the GeofenceManager class to manage your Geofences, as it will allow you to effectively track an unlimited number of regions.

  • Constructor Details

    • Geofence

      public Geofence(String id, Location loc, int radius, long expiration)

      Constructor

      Parameters

      • id: unique identifier

      • loc: the center location of this Geofence

      • radius: @param radius the radius in meters. Note that the actual radius will vary on an actual device depending on the hardware and OS. Typical android and iOS devices have a minimum radius of 100m.

      • expiration: the expiration time in milliseconds. Note that this is a duration, not a timestamp. Use -1 to never expire.

  • Method Details

    • createDistanceComparator

      public static Comparator<Geofence> createDistanceComparator(Geofence refRegion)
      Creates a comparator for sorting Geofences from the current Geofence.

    • createDistanceComparator

      public static Comparator<Geofence> createDistanceComparator(Location refPoint)
      Creates a comparator for sorting Geofences from the given reference point.

    • getId

      public String getId()

      Gets the Geofence ID.

      Returns

      the id

    • getLoc

      public Location getLoc()

      Gets the location of the Geofence.

      Returns

      the center Location

    • getExpiration

      public long getExpiration()

      Gets the expiration duration (from now) of the Geofence in milliseconds.

      Returns

      the Geofence expiration

    • getRadius

      public int getRadius()

      Gets the radius of the geofence in metres. Note that the actual radius will vary on an actual device depending on the hardware and OS. Typical android and iOS devices have a minimum radius of 100m.

      Returns

      Geofence radius

    • getDistanceTo

      public double getDistanceTo(Geofence gf)

      Gets the distance between the current region and the given region.

      Parameters
      • gf

    • equals

      public boolean equals(Object o)

      Geofences are equal if their id, radius, and expiration are the same, and the location latitude and longitude are the same.

      Parameters
      • o
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Description copied from class: Object
      Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by java.util.Hashtable. The general contract of hashCode is: Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result. It is not required that if two objects are unequal according to the equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hashtables. As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)
      Overrides:
      hashCode in class Object