How to measure the amplitude of a microphone while recording with audiorecord in android?

I am recording audio using audiorecord in android and at the same time I want to be notified of the amplitude of the input voice. I want to send peak values ​​at a time interval as input to my service. Is it possible. Also wanted to know how to get a notification when an audio file is finished while playing a media file with an audio track.

the link I'm working on is

http://androidgenuine.com/?tag=sound-record-android-modify-voice-on-android