How to set out put files to save at user selected path?

Hello All, This question is in continuation with following question: http://in.mathworks.com/matlabcentral/answers/287928-select-a-folder-to-save-output-files

Now from above answer I was able to set and select the output folder but I am not able to save the files in there.

Here is what I tried. The following code is below the push button:

input = get(hObject,'String');
%checks to see if input is empty. 
if(isempty(input))
  h=msgbox('Please select the output folder');
end
guidata(hObject, handles);
selected_dir = uigetdir();
set(handles.edit27, 'String', selected_dir)

Now in my another push button where the calculations happen, I want to save the output images in above selected path. So this is what I have done. The following is the code which I am having the calculation push button callback:

saveas(gcf,fullfile(selected_dir,1),'jpg');
close(gcf);

I am getting following error.

Undefined function or variable 'selected_dir'.

What I want is to save 1.jpg as output file in user selected folder. Also I want to display "Please select out put folder" message if user forgets to select it.

Answer 1

[Weird Rando]

You have to set selected_dir as a global variable so that other section of the gui can access it.

[adi kul]

Great! Solved one of my problem. Can you give me the solution regarding displaying "Please select out put folder" message if user forgets to select it?

[Stephen23]

"selected_dir as a global variable" is not good advice. Using globals is a terrible way to pass information:

http://blogs.mathworks.com/videos/2010/03/08/top-10-matlab-code-practices-that-make-me-cry/

There are plenty of discussion on this forum about why globals should be avoided:

http://www.mathworks.com/matlabcentral/answers/51946-systematic-do-not-use-global-don-t-use-eval

http://www.mathworks.com/matlabcentral/answers/21541-variable-global-or-in-guidata

http://www.mathworks.com/matlabcentral/answers/74626-how-to-declear-global-array-and-how-to-use-it

Rather than learning to code by following bad advice, just follow the MATLAB documentation, which explains faster, more robust ways to pass data between GUI callbacks:

http://www.mathworks.com/help/matlab/creating_guis/share-data-among-callbacks.html

Isn't it amazing: the MATLAB documentation actually tells us good ways to use MATLAB, so we don't have to rely on bad advice from the random strangers. Sadly on this forum it is sometimes a case of caecus caeco dux, and bad advice gets copied and repeated, regardless of the advice from more experienced users, and even TMW themselves:

http://www.mathworks.com/matlabcentral/answers/283294-for-loop-for-variables#answer_221435

[Weird Rando]

@adi: Can't you just implement a button and have it check if the textbox properties when its click?

@Stephen: I'm just answering the question. Feel free to your submit the answer below

[Stephen23]

@Weird Rando: and I'm just pointing out why using globals is universally considered a bad way to write code. I didn't invent this idea: even the official MATLAB blogs give the advice to avoid using globals!

If you ask for advice from someone, which information would you prefer to be given:

1. a reliable and robust solution, or
2. a solution that is avoided by all experts ?

I know which one I would want to learn.

In any case my comment written not just for you, but also for anyone who reads this page and who should be informed that globals are a buggy and slow solution. They deserve to know this: would you expect to find good advice on MATLAB Answers, or buggy advice? Which would you want to use?

[Muhammad Usman Saleem]

you are awesome @Stephon

Answer 2

[Stephen23]

Here is the MATLAB documentation page which explains all of the recommended ways to pass data between callbacks, including lots of working examples:

http://www.mathworks.com/help/matlab/creating_guis/share-data-among-callbacks.html

Note that globals are not listed.