Detecting Callstate on phone

Hi

A customer needs to see if an employee is busy on the phone (IOS/Android) before trying to call them.

I am looking for a way to monitor callstates on a device, and have tried the example in the Delphi Cookbook by Daniele Teti and also this example:

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Mobile_Tutorial:_Using_the_Phone_Dialer_on_Mobile_Devices_(iOS_and_Android)

However, none of them works, at least not on my Samsung S7 phone, I can get carrier information end more, but no callstates.

Have anybody gotten the example to work, or have other suggestions on how I can solve this problem?

Michael