I'm interested in creating a seek button panel (2 buttons - back and forward) that will connect with my Android's native music player, similar to the CD player in my car.

I'd like for the buttons to have dual-operations:

1. Seek backwards/forward in the duration of a specific track
2. Seek backwards/forward between tracks in a playlist

I'm contemplating on how this works in my car, in order to build it on my own - is there:

A different voltage going through the circuit when the button is pressed longer

or

Is there some sort of timer in the micro-controller's code that tells it to send a different order when the button reaches a certain period of time being pressed?

Please pay attention to both parts of my question - how this actually works, and how should I go about building it on my own - preferably using Arduino, as per I've got one lying around.

Feel free to correct me if I'm making terminology errors - I'm more of a web kind of guy, this hardware stuff is new to me.