A problem with progress bar is that you need to know how many files your are going to process, in advance.
If you are going to copy some thousands of files, it may last some seconds.
If you do not need to copy so many files, you could use Array<String> SearchFile(String dir, String condFile), that retrieves you a list of files under dir that complies condition condFile. After calling it, you can do a for copying all files and moving a progress bar.