How to use GUI to change a value of a variable and use that variable in a script

Hi!

I have a program that opens a GUI while its running, the thing is I want the user to press one of the buttons on the GUI. the user selection should change the value of the variable. and then the main program continue running after the GUI.

my problem is that I don't know how to make a button event and how to get the value of the variable back to the main program?

[Adam]

https://uk.mathworks.com/help/matlab/ref/dialog.html

gives an example. You can also do it in GUIDE, using the OutputFcn and a modal GUI utilising uiwait to ensure the OutputFcn only triggers when you close the dialog.

[Nora Khaled]

thank you

Answer 1

[Jan]

You can either use GUIDE or create the GUI prgrammatically by code. Perhaps a simple inputdlg, questdlg or listdlg is sufficient already. See

doc inputdlg
doc questdlg
doc listdlg

Creating an own dialog and obtaining a value is easy also:

function Reply = myFirstGUI
FigH = figure('Position', [100, 100, 400, 300], ...
              'Menubar', 'none');
ButtonH = uicontrol('Style', 'PushButton', 'String', 'Click me!', ...
              'Position', [20, 20, 360, 30], ...
              'Callback', {@myCallback, FigH});
disp('Waiting for the figure to close...');
uiwait(FigH);
disp('Waiting was resumed...');
delete(FigH);
Reply = '???'  % You did not explain, how the GUI creates the value to be replied
end

function myCallback(ButtonH, EventData, FigH)
disp('Button was pressed.');
uiresume(FigH);
end

Now call this from the main function:

Reply = myFirstGUI();

[Nora Khaled]

thank you.

Answer 2

[Walter Roberson]

Example:

   faster_button = uicontrol('style','push', 'UserData', 0, 'callback', @faster);

and

   function faster(hObject, event)
      current_speed = get(hObject, 'UserData');
      current_speed = current_speed + 10;
      set(hObject, 'UserData', current_speed);

and

   while true
     current_speed = get(faster_button, 'UserData');
     x = x + current_speed;
     scatter(x, current_speed);
     hold on;
     pause(1);    %also triggers drawing
   end

Note here that pushing the button does not force the script to change the value it is using: the script has to ask what the current value is.

[Nora Khaled]

thank you.