Android Wifi Direct: How To Send Data From Group Owner To The Clients?

I've got a problem using wifi direct. I managed to connect 2 devices and send data from the client to the group owner, because the group owner ip is the one that everybody knows. I

Solution 1:

Like Laszlo Magyar said, you need to sent an empty message to server first so that server can use client socket to get the incoming ip address.

My solution is to send an string to server from client so server CAN know the client's ip address, and the rest of process is the same.