How can i get one GUI to trigger another GUI?

I have two GUI's running together simulating the running of a ships engine room. The main GUI (GUI_1) runs a while loop, started with a button press, calculating stuff like fuel consumption, propeller thrust and ship speed. The while loop runs continuously while the button is pressed but has a 0.2 sec pause build in. In the second GUI (GUI_2) I would like to display additional data as well as plots of selected parameters calculated in the main GUI. I have managed to pass data between the GUI's with the setappdata getappdata method. Getting continuously updating data from GUI_2 to GUI_1 works fine because the getappdata is included in the while loop in GUI_1. I can get data from GUI_1 to GUI_2 but so far it only updates on activation of a button in GUI_2, not continuously. My question is how do I trigger GUI_2 to receive and display data from GUI_1 continuously (or at the same 0.2 sec iteration as GUI_1)?

I tried putting a while loop in GUI_2 but that made the program stall (I am guessing GUI_1 just waited for the GUI_2 loop to finish, which it did not do since there was no end to the loop)

The GUI's are created in GUIDE, no toolboxes are in use and I am running the r2015b academic version of MATLAB. Thank you for your help.

Answer 1

[Niels]

What you could do is add a listener in GUI_2 to an object in GUI_1 that is updated when your while-loop is being executed. You could use the callback function to define anything that needs to be updated.

See below dummy code.

GUI_1

function GUI_1

hs.hFig = figure('Menubar','none', 'Visible','On', 'Name','GUI_1', ...
                'Units','Pixels', 'Position',[100 100 300 300]);

hs.startLoop    = uicontrol('Style','togglebutton', 'Parent',hs.hFig, ...
                            'String','Start!', 'Tag','StartLoop', ...
                            'Units','Normalized', 'Position',[0.1, 0.5, 0.8, 0.4], 'Callback',@whileLoop);

hs.indicatorBox = uicontrol('Style','text', 'Parent',hs.hFig, ...
                            'String','Press the button...', 'Tag','iBox', ...
                            'Units','Normalized', 'Position',[0.1, 0.2, 0.8, 0.1]);

hs.randomValue  = uicontrol('Style','text', 'Parent',hs.hFig, ...
                            'String','0', 'Tag','rValue', ...
                            'Units','Normalized', 'Position',[0.1, 0.05, 0.8, 0.1]);
guidata(hs.hFig, hs)

end

function whileLoop(hObj, ~)

hs = guidata(hObj);

set(hs.indicatorBox,'String','While-loop active!')
set(hs.startLoop, 'String', 'Running!')

while true
    drawnow
    if ~hObj.Value
        set(hs.indicatorBox,'String','Stopped. Press the button...')
        set(hs.startLoop, 'String', 'Stopped!')
        break;
    end

      set(hs.randomValue, 'String', num2str(rand,'%.2f'))
      hs = guidata(hObj);

      pause(0.2)
  end

end

GUI_2

function GUI_2

hs.hFig = figure('Menubar','none', 'Visible','On', 'Name','GUI_2', ...
                'Units','Pixels', 'Position',[400 100 300 300]);

hs.randomValue = uicontrol('Style','text', 'Parent',hs.hFig, ...
                            'String','0', 'Tag','rValue');

theOtherFigure = findobj('Type','figure','Name','GUI_1');

hs2 = guidata(theOtherFigure);

hs.myListener = addlistener(hs2.randomValue, 'String', 'PostSet', @UpdateInThisGUI);

guidata(hs.hFig, hs)

end

function UpdateInThisGUI(varargin)

hs  = guidata(findobj('Type','figure','Name','GUI_2'));
hs2 = guidata(findobj('Type','figure','Name','GUI_1'));

set(hs.randomValue,'String', hs2.randomValue.String)

end

A nicer way might be to create a class for your data with a custom event that is triggered whenever your data is updated. For that, you'd have to look into MATLAB's OOP functionality.

[Stig Eriksen]

Hi Niels. Thank you very much for the answer, I can definitely see how the listener would be the way to go. Being a MATLAB novice however I cannot figure out how to implement it in my GUIDE generated GUI. Where should I place the listener? Should it be just after the part where GUI2 is made visible? My code is quite long (>1000 lines by now) so i dont think its a good idea to paste it all here. I could create and paste a shorter code that looks like it if it would help

[Niels]

I have never used GUIDE (just cannot get used to its output), but I think it should be possible to do this in your OpeningFcn for GUI_2.

The alternative would be to add some kind of "start sync"-button in GUI_2 where you could create the listener in its corresponding callback function.

[Stig Eriksen]

After a good deal of messing around I finally got the listener working, thanks for the help

[Niels]

Good to hear. How did you implement it in the end? :)

Answer 2

[Jan]

Instead of a while loop, a timer can trigger the updates more reliably in both GUIs.