How to load sound in android-(load music files from raw folder)

int rID = getResources().getIdentifier("sound" + i, "raw",
"package name");
if (mp != null) {
try {
if (mp.isPlaying()) {
mp.release();
mp = null;
}
} catch (Exception e) {
mp = new MediaPlayer();
}
}
;
if (mp == null) {
mp = new MediaPlayer();
}
mp = MediaPlayer.create(ZooAlphaMain.this, rID);
mp.start();