wait for GUI data to continue the script

Hi,

I have a script which call a function (a GUI). Inside the GUI, I want to collect responses (selected radiobuttons) to multiple question and then based on the answers, continue the main script. My idea was to put the answers in the user data of the figure (GUI) and then check that in the script. My problem is that when I run the main script, it does not wait for the data. I do not know how much time to wait for the user data (so I cannot use pause(t)). The last thing that came to my mind, was using a while after calling the GUI, so that when the current figure's userdata becomes non-empty the script goes on. However, it does not allow me to interact with the GUI!

Here's my code for the GUI:

function tesst()
set(0,'units','pixels')

% get screen size
screenrect = get(0,'screensize');
%open a figure 
fg = figure('Position',screenrect, ...
            'menubar','none','resize','off','NumberTitle','off');
S.ax = axes('unit', 'pix', 'position',screenrect);
question_test = imread('question_test.JPG');
image(question_test,'Parent',S.ax)
axis off
% define a button area 
bg_pos = [590 15 40 195];
S.bg = uibuttongroup(fg,'unit','pix','pos',bg_pos,...
    'backgroundcolor','w');
% size of the radio_buttons
rd_size = 15;
left_edge_rd = round((bg_pos(3) - rd_size)/2);
S.rd(1) = uicontrol(S.bg, 'style', 'rad', 'unit', 'pix', 'position',...
    [left_edge_rd 170 rd_size rd_size],'backgroundcolor', 'w');
S.rd(2) = uicontrol(S.bg, 'style', 'rad', 'unit', 'pix', 'position',...
    [left_edge_rd 130 rd_size rd_size],'backgroundcolor', 'w');
S.rd(3) = uicontrol(S.bg, 'style', 'rad', 'unit', 'pix', 'position',...
   [left_edge_rd 90 rd_size rd_size],'backgroundcolor', 'w');
S.rd(4) = uicontrol(S.bg, 'style', 'rad', 'unit', 'pix', 'position',...
   [left_edge_rd 50 rd_size rd_size],'backgroundcolor', 'w');
S.rd(5) = uicontrol(S.bg, 'style', 'rad', 'unit', 'pix', 'position',...
   [left_edge_rd 10 rd_size rd_size],'backgroundcolor', 'w');
set(S.bg,'SelectedObject',[]);
next = imread('next.jpg');
uicontrol('style', 'pushbutton', 'pos' , [50 55 75 50],...
'fontsize', 18, 'cdata', next, 'callback' , {@next_callback});

count_que = 1;
max_questions = 2; %for now

question_ans = [2;3];
selected_ans = zeros(size(question_ans));

    function next_callback(~,~) %go to the next question

        for count_ans = 1:5
            if get(S.bg,'SelectedObject') == S.rd(count_ans)
                selected_ans(count_que) = count_ans;
            end
        end
        fprintf("Question number: %d Participant's answer:%d\n",count_que,selected_ans(count_que))
        if count_que >= max_questions
            %if passed return true, else return false
            fg.UserData = selected_ans(1);
            waitforbuttonpress;
        else
            count_que = count_que + 1; %go to next question
            question_test = imread(['question_test' int2str(count_que) '.jpg']);
            image(question_test)
            axis off
        end
    end
end

When the question reaches its end (by updating count_que after each next_callback press), I update the userdata and it becomes non-empty.

And here's a sample code for the main script:

tesst()
pause(1) %I used this pause to allow the GUI to get opened!
s = 2;
while isempty(get(gcf,'UserData')) == true
end

if s == get(gcf,'UserData')
    disp('hoora')
else
    disp('Damn it!')
end

Answer 1

[Walter Roberson]

If you use uiwait() and pass in a figure, then MATLAB will wait for the figure to be deleted.

If you use waitfor() and pass in (only) a figure, then MATLAB will wait for the figure to be deleted.

If you use waitfor() and pass in an object and a property name, the MATLAB will wait for the property of the object to change state.

You can name the UserData property as the property to be watched.

while isempty(get(gcf,'UserData')) == true

Caution: gcf changes if the user deletes a figure, or if the user clicks on a different figure. Including if they click on the figure as part of moving it aside visually for some reason that has nothing to do with the computation.

It is therefore safer to record the relevant figure handle first, and then refer to that figure handle, so that you do not accidentally switch attention to something else.

[Zahra Arj]

Many thanks Walter!

The problem was solved using waitfor(figurehandle, 'UserData')