Android：构建多边形形状地理围栏

Question

According to the API documentation, only Circular shape Geofences allowed:

https://developers.google.com/android/reference/com/google/android/gms/location/Geofence.Builder

And it's looks for example: https://developer.android.com/training/location/geofencing.html

But I have 4 locations, representing 4 corners of rectangle, and I want my Geofence to be that rectangle.

I want to avoid solution of building my custom location monitoring service extending the functionality of monitoring Geofences, because I think this kind of services are CPU & power consuming...

Thanks,

Answer 1

You have to do it by yourself (however I think it's rather senseless - geofences/location services are inaccurate enough to not even be able to alert about circles, don't even think about some other concrete shape).

Create smallest circular geofence which contains your polygon and if triggered just check if you are in the polygon inside with Google Maps Android API utility library .

In other words check if you are in white area not in grey:

Answer 2

The Android Geofencing API only provides support for Circular Geofences. If you want to monitor Polygon shaped geofences then you have to implement it your self.

One solution would be something like this:

Get the current location update using Location API.

Now you have polygon shaped geofence. You can use ray-casting Algorithm to check if a point is inside the Closed Polygon or not?