Create a CompositeFile as a member variable in MediaPlayerFragment (should eventually end up somewhere else)
jump() logic using CompositeFile (switching between files when necessary)
Only seekTo new time in file if new file successfully loads into the media player - otherwise don't seek anywhere at all
Only setDataSource on media player if the file to be played has changed.

This avoids calling setDataSource() on the same file name, defensively avoiding any overhead
in re-loading the same file, or other unwanted effects on playback due to MediaPlayer behavior
(eg. re-starting at the beginning of the file, pausing playback, etc.)
Create method getFileEntry(String filePath)