How to create PhoneStateReceiver get CLI and call events

During first 5 years of my career I luckily worked at software houses that created computer telephony related software, I had used Microsoft TAPI and Dialogic APIs to create IVR and Operator Console and Call Recorder software. When I first started Android programming in 2010, I was very curious about phone states and CLI. 

I later figured it out and came to know that a BroadcastReceiver will be the right thing to use in this case. BroadcastReceiver is a specially designed component offered by Android OS, and it is used to handle various broadcasts sent by apps or OS components. The broadcasts related to telephone call states are sent by TelephonyManager which is a component of Android OS. The phone state receiver given below can be used in scenarios like call blocking, call tracking, and sending information to http or cloud based servers. This salient features of my phone state receiver are given below Get the CLI from an incoming call Get the dialled number from an outgoing call When an inbound call is connected, get informed When a call is disconnected, get notified