Hello,
realize the work so that it is possible to collect audio and telephone number of the device and send the data to a webservice and display the audio and the number plus the ability to view the status, ie if the call was made or received by example .
The app will be running in the background constantly listening for connections and capture all traffic.
The app will work on devices with android 2.2 to 4.4 in most cases. Depending on the manufacturer and privacy policies, it can for example restrict the collection of the telephone number, like samsung, but not the audio.
Questions, information, etc., do not hesitate to ask =)