Android - Need to add more than 100 geofences

问题

I'm developing an application where user can set multiple locations. I get succeed to show notifications when user get Enter or Leave specific region using GeoFencing.

Now, there is situation that i need to provide monitoring for all saved locations and it can be hundreds and more. I've read at the given link "You can have multiple active geofences, with a limit of 100 per device user."

Is there any way add more then 100 geofences per device user ?

Thanks!

回答1:

1. Have an ArrayList with all the geofences you want to monitor +100.
2. Listen to location updates.

3. When you get a location update, if the ArrayList of all your geofences is more than 100, remove all geofences been monitored and then calculate the 100 nearest geofences using the harvesine formula:

   public static final double R = 6372.8; // In kilometers
   
   public static double haversine(double lat1, double lon1, double lat2, double lon2) {
     double dLat = Math.toRadians(lat2 - lat1);
     double dLon = Math.toRadians(lon2 - lon1);
     lat1 = Math.toRadians(lat1);
     lat2 = Math.toRadians(lat2);
   
     double a = Math.sin(dLat / 2) * Math.sin(dLat / 2) + Math.sin(dLon / 2) * Math.sin(dLon / 2) * Math.cos(lat1) * Math.cos(lat2);
     double c = 2 * Math.asin(Math.sqrt(a));
     return R * c;
   }
   

   That will give you the distance between the two locations. After that you could compare that distance with the geofence region radius to know if is inside the region.

Note: This distance will be in kilometers if your radius is on meters then just multiply the haversine method result with 1000 so that it's converted to meters.

Reference

4. Start monitoring the result list of the 100 nearest geofences.

This will allow you to always monitor the 100 nearest geofences based on your location. Been able to monitor more than 100 since it will change the monitoring geofence regions always to the 100 nearest geofence regions.

来源：https://stackoverflow.com/questions/29670504/android-need-to-add-more-than-100-geofences