Command Window Output to GUI

Hello everyone,

I'm creating a GUI and at some point of it I need to run some cshells that begin printing many notifications in the command window. This all works fine, however, it would be great if all that output can be printed in the GUI itself. Is there a way of doing this? Sort of like cloning the command window into a "Static Text" field or similar in the GUI.

Any help is appreciated.

Answer 1

[Image Analyst]

See if diary() or echo() can help you do what you want.

[carlos Uribe]

This gives me an output to a file that I haven't been able to update on the GUI

[Image Analyst]

Then you may have to change the functions that are spewing the stuff to the command window to return the text in a string instead. If it just sort of freely spews text out asynchronously to the command window, then you may be out of luck.

Try Yair Altman's site: http://undocumentedmatlab.com/

Answer 2

[Yair Altman]

You can access the CW text programmatically as follows:

jDesktop = com.mathworks.mde.desk.MLDesktop.getInstance;
jCmdWin = jDesktop.getClient('Command Window');
jTextArea = jCmdWin.getComponent(0).getViewport.getView;
cwText = char(jTextArea.getText);

You can place a callback that will update your GUI whenever new text is added to the CW:

set(jTextArea,'CaretUpdateCallback',@myUpdateFcn)

More details on how the CW works internally can be found in:

• http://undocumentedmatlab.com/blog/cprintf-display-formatted-color-text-in-command-window/
• http://undocumentedmatlab.com/blog/setprompt-setting-matlab-desktop-prompt/

[Luis Camilo]

Yair, you have an exemple for this (.m)? I need show the command window in GUIDE that is compiled .exe.tanks

[Aditya]

Hi Luis,

I'm facing the sam eproblem. I need to display command window output to a guide gui. Have you figured out a way to solve this?

[mashor housh]

Hi Adita and Luis,

In case you deal with compiled GUI you can compile it with console option enabled, then you can call it in batch file: myprgram.exe > output.txt the output file could be read from your GUI callback.

The above solution will create console window whenever you open the program. if you do not want the console window to appear then you may build another m-file (say start_myprgram.m) containing the following line "dos('myprogram.exe > output.txt')" you can compile start_myprgram.m as your main program file.

[Chris]

Yair,

Do you know how this would be accomplished for a "MATLAB Command Window" using the -nodesktop mode? I'm trying to run an invisible automation server and capture the command output as part of the GUI, but am unsure of how to access the text in the Command Window.

[Muhammad RSMY]

I tried the code but unfortunately doesn't work, maybe I code it wrong, cause I am new in coding

[Trevor Harris]

This doesn't seem to function for a GUI that I'm trying to compile. I'm using 2017b.

When I first compiled I got an error at the "jTextArea = jCmdWin.getComponent(0).getViewport.getView;", saying I was asking for a reference from a non-struct object.

I then re-complied not suppressing the output from the jDesktop and jCmdWin lines. The jDesktop line seems to run fine and I get a com.mathwors.mde.desk.MLDesktop@127a7a2e... but the jCmdWin line yields an empty double. Any idea what may be going on? Has matlab changed this functionality since this post?

[Hao Li]

The same problem.

Before compiling, everything worked just fine.

After compiling, jCmdWin = jDesktop.getClient('Command Window') yeilds empty.

[Image Analyst]

What version are you using? Did you compile with the -m option or the -e option? If the -e option, there is no console window so that would explain it. If -m then perhaps the compiled version does not consider the console window to be the "command" window.

[Yair Altman]

Compiled applications that have a console use plain-text output, and do not send output to a Desktop window ("client") called "Command Window". Such a window is only available when you use the Matlab Desktop, and not in compiled apps (which do not display the Desktop).

The trick that I showed above uses Java code to query the text displayed in the "Command Window" client window. Compiled apps do not have such a window, so you can not query their text.

You need to programmatically redirect console output to your GUI using dedicated commands, and not rely on simple fprintf() commands.

Answer 3

[crawler]

To use the method by @Yair Altman, you can make the intialisations (setting callbacks etc..) at the startp function of the window containing the console e.g.

function startupFcn(app)
    try
        jDesktop = com.mathworks.mde.desk.MLDesktop.getInstance;
        jCmdWin = jDesktop.getClient('Command Window');
        jTextArea = jCmdWin.getComponent(0).getViewport.getView;
        set(jTextArea,'CaretUpdateCallback',@app.setPromptFcn)
    catch
        warndlg('fatal error');
    end
end

You can add a textarea at the window to display the console text.

Then you can make a private function for the event handler as such:

methods (Access = private)
        
        function setPromptFcn(app,jTextArea,eventData,newPrompt)
           % Prevent overlapping reentry due to prompt replacement
          persistent inProgress
          if isempty(inProgress)
            inProgress = 1;  %#ok unused
          else
            return;
          end
         
          try
            % *** Prompt modification code goes here ***
            cwText = char(jTextArea.getText);
            app.TextArea.Value = cwText;
            % force prompt-change callback to fizzle-out...
            pause(0.02);
          catch
            % Never mind - ignore errors...
          end
         
          % Enable new callbacks now that the prompt has been modified
          inProgress = [];
         
        end  % setPromptFcn
    end

Writing the callback function tis way prevents entering an endless loop.

You can write whatever you like between the try statement here, to change how the callback behaves

[Prajwol Tamrakar]

Excellent! Thank you!!

[Michael]

I appreciate that this this is pretty old, but I'm trying to accomplish the same...capture sent to the command window and display it in a text area (named jTextArea for simplicity) in an App Designer app (not compiled). The error I'm recieving is "Dot indexing is not supported for variables of this type." at the line "jTextArea = jCmdWin.getComponent(0).getViewport.getView;". I was prompted to refer to JTextArea as app.JTextArea, but doing to made no difference.

Many thanks for any assistance.

[Walter Roberson]

@Michael

Which MATLAB release are you using? Support changed in R2025a.

[Michael]

R2025b...thx.

Answer 4

[Jack Chynoweth]

I have appiled this method, and got to work in the matlab enviroment.

I have now converted it to a standalone app, and it is catching an error.

is there a way to apply the method to standalone appilcations?

[Yair Altman]

As already noted above, accessing the command window text does not work in compiled applications. Read above for details