The Pebble watch has a Intent that is globally sended when the Pebble is connected/disconnected. This allow the phone apps to know if the watch is connected or not. I have s
As akmal said you can get devices which are connected to the phone, But to know whether the wearable currently connected with handheld
List connectedNodes =
Wearable.NodeApi.getConnectedNodes(mGoogleApiClient).await().getNodes();
The list contains data like this:
Node{Moto 360 6BBF, id=3b6d19bf, hops=1, isNearby=true}