How to detect Input data through Audio Jack

My android project has a requirement to read RFID Card through Audio jack .To achieve this I am running a thread to open the audio jack (native)and receive the input data .But my approach is non intuitive ,I have to swap the card with in the given time interval of thread ,but this is not the requirement . My requirement is When ever there is a Rfid Card swip I have to Update the UI .

So basically I need a listener which will listen to audio port when ever there is a new swip i.e input data to phone .Can some one help me with this ??