1. Create a directory called raw in the res directory of your project (if the directory does not exist).
2. Save your audio file in the raw directory. Example: res\raw\myaudio.ogg
The supported audio types are:
.3gp, .mp4, .m4a, .aac, .flac, .mp3, .mid, .xmf, .mxmf, .rttl, .rtx, .ota, .imy, .ogg, .mkv, .wav
More information on the media types for android is here.
Make sure the filename is all lower case, with no spaces.
Correct: mysong.mp3
Incorrect: My Song.mp3
3. Compile and run!