Call Hangup Event

I want an event to be raised in service when call is disconnected.
I could found any thread in forum so i thought google for native code
I found http://developer.android.com/reference/android/telephony/PhoneStateListener.html#LISTEN_CALL_STATE

Answer clearly explain how to do in native java ...but can anyone help me in using in it B4A.
i will appreciate his help.