You can use uigetfile() with 'multiselect', 'on' .
The first output of uigetfile() will be numeric if the user cancelled.
The first output of uigetfile() will be a character vector if the user selected exactly one file.
The first output of uigetfile() will be a cell array of character vector if the user selected more than one file.
I suggest using something like,
[selfiles, selpath] = uigetfile('*.txt', 'multiselect', 'on');
if isnumeric(selfiles); return; end %user cancel
filenames = fullfile(selpath, cellstr(selfiles));
After that, filenames will be a cell array of character vectors of fully-qualified file names; you will not need to test for the special case that the user selected exactly one file.
