Navigating Files on a SD card

Hi all, I am new to programming so wanted a little help, I am trying to build a WAV player, where user will be open to navigate between the files and then select the open they want to play. Moving down the list of file can be done with "root.openNextFile();" function but is there a way of opening previous file. I just want to move up and down the WAV files in the SD card.

Any Help will be wonderful

Thanks Sorry meant to post it in the programming forum, can someone delete this post please. Thanks you