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How to display long text in a GUI window, input to textscan for generic textfiles.

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Hey guys,
i would like to display long text in a new GUI after pushing a pushbutton. The text is stored in a textfile. I found this code that shall create the GUI i need.
%# read text file lines as cell array of strings
fid = fopen( fullfile('C:\Users\powersyslab\Desktop\license.txt'));
str = textscan(fid, '%s', 'Delimiter','\n'); str = str{1};
%# GUI with multi-line editbox
hFig = figure('Menubar','none', 'Toolbar','none');
hPan = uipanel(hFig, 'Title','Display window', ...
'Units','normalized', 'Position',[0.05 0.05 0.9 0.9]);
hEdit = uicontrol(hPan, 'Style','edit', 'FontSize',9, ...
'Min',0, 'Max',2, 'HorizontalAlignment','left', ...
'Units','normalized', 'Position',[0 0 1 1], ...
%# enable horizontal scrolling
jEdit = findjobj(hEdit);
jEditbox = jEdit.getViewport().getComponent(0);
jEditbox.setWrapping(false); %# turn off word-wrapping
jEditbox.setEditable(false); %# non-editable
set(jEdit,'HorizontalScrollBarPolicy',30); %# HORIZONTAL_SCROLLBAR_AS_NEEDED
%# maintain horizontal scrollbar policy which reverts back on component resize
hjEdit = handle(jEdit,'CallbackProperties');
set(hjEdit, 'ComponentResizedCallback',...
Unfortunately i get the error:
Error using textscan
Invalid file identifier. Use fopen to generate a valid file identifier.
How can i adapt the inputs of the textscan function so that it can read generic text. Because the text i need is not formatted in a special way. It is just lines of text and numbers but in no specific order.
I would be glad for help!
Best regards, John
John on 11 Sep 2015
Oha you are right, sryyy, i really chose the wrong path to my textfile:(
now i have another error occuring:
Undefined function 'findjobj' for input arguments of type 'double'.
How can that be? i took a look in the documentary of findobj but everything seems fine. Findobj just needs a handle to an object and that is given by 'hEdit'.
I dont get the mistake.
Best regards, John
Terence Etchells
Terence Etchells on 16 Nov 2018
Edited: Terence Etchells on 16 Nov 2018
If you are here you may have encountered a problem with your GUI
If you are running R2018b or later you will need to download Yair Altman's latest version of findjobj.m from
there is a bug fix for R2018b.
Terence Etchells

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Accepted Answer

Guillaume on 11 Sep 2015
The error you're getting is nothing to do with reading generic text. It's telling you that the fid you're passing to textscan is not valid. Most likely, it's not valid because fopen failed to open the file (due to not being present, not having permission or a million other possibilities).
You could change the beginning of the code to:
[fid, errmsg] = fopen( fullfile('C:\Users\powersyslab\Desktop\license.txt'));
if fid == -1
In general, when dealing with files / user input, it's always a good idea to check that the input received is what you expect.
Guillaume on 11 Sep 2015
One of two things:
- your code indeed intend to use findobj, in which case the syntax you're using is incorrect. You're only telling findobj where to search, but not what to search for.
- the code did indeed intend to use a function called findjobj, not part of matlab. Most likely, the one written by Yair, available < here>.
I'd lean toward the latter.

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