public static String extractMusicIDFromMediaID(@NonNull String mediaID){
  int pos=mediaID.indexOf(LEAF_SEPARATOR);
  if (pos >= 0) {
    return mediaID.substring(pos + 1);
  }
  return null;
}

public static String extractMusicIDFromMediaID ( @ NonNull String mediaID ) { int pos = mediaID . indexOf ( LEAF_SEPARATOR ) ; if ( pos >= 0 ) { return mediaID . substring ( pos + 1 ) ; } return null ; }
extracts unique musicid from the mediaid . mediaid is , by this sample ' s convention , a concatenation of category ( eg " by_genre " ) , categoryvalue ( eg " classical " ) and unique musicid . this is necessary so we know where the user selected the music from , when the music exists in more than one music list , and thus we are able to correctly build the playing queue .
