Matlab makes the loops run simultaneously

Question

Unfortunately, I have two loops. that\'s why my code makes the first loop run and only when it is finished, it makes the second loop run.

But I want the gui to show the

Answer 1

Is this what you want? Just combine the loop bodies.

for i=1:200
    if mod(i,2) == 0
        set(hAxes,'Color','b');
    else
        set(hAxes,'Color','g');
    end

    image2 = horzcat('now processing ', 'image', num2str(i), '.jpg of 200 images');
    set(loading1,'string',image2);
    drawnow;
end

EDIT: OK, in that case, try a timer instead of the first loop

function output = main_function

% Your other setup calls
hAxes = axes('Parent',hFigure,'Units','pixels','Position',[0 112 424 359]); 

c = 0;
t = timer('TimerFcn', @color_change_fcn, 'Period', 1.0);
start(t);

for i=1:200
    image2 = horzcat('now processing ', 'image', num2str(i), '.jpg of 200 images');
    set(loading1,'string',image2);
    drawnow;
end

function color_change_fcn
    if mod(c,2) == 0
        set(hAxes,'Color','b');
    else
        set(hAxes,'Color','g');
    end
    drawnow;
    c = c + 1;
end
end

Just remember that the MATLAB control flow is inherently single-threaded, so these callbacks won't run if MATLAB is busy working somewhere else.

Answer 2

This seems to be related to your previous question, where you want the two loops to be running simultaneously (well at least appear to be that way).

Building on @Peter's answer, consider the following working example:

function timerDemo()
    %# prepare GUI
    hFig = figure('Menubar','none', 'Resize','off');
    axes('XLim',[0 1], 'YLim',[0 1], 'Visible','off', ...
        'Units','normalized', 'Position',[0.1 0.2 0.8 0.6])
    hTxt = uicontrol('Style','text', 'FontSize',24, ...
        'Units','normalized', 'Position',[0 0.9 1 0.1]);
    hPatch = patch([0 0 1 1 0],[0 1 0 1 0],'k');

    %# colors to cycle through
    c = 1;
    clr = lines(4);

    %# create timer
    delay = 0.5;
    hTimer = timer('Period',delay, 'StartDelay',delay, ...
        'ExecutionMode','FixedRate', 'TimerFcn',@timerCallback);

    %# when figure is closed
    set(hFig, 'CloseRequestFcn',@onClose);

    %# process images
    start(hTimer);          %# start timer
    for i=1:100
        if ~ishandle(hFig), break; end

        msg = sprintf('Processing image %d / %d', i, 100);
        set(hTxt, 'String',msg)

        %# some lengthy operation
        pause(.1)
    end
    if isvalid(hTimer)
        stop(hTimer)        %# stop timer
        delete(hTimer)      %# delete timer
    end

    %# timer callback function
    function timerCallback(src,evt)
        if ~ishandle(hFig), return; end

        %# incremenet counter circularly
        c = rem(c,size(clr,1)) + 1;

        %# update color of patch
        set(hPatch, 'FaceColor',clr(c,:));
        drawnow
    end

    %# on figure close
    function onClose(src,evt)
        %# stop and delete timer
        if isvalid(hTimer)
            stop(hTimer);
            delete(hTimer);
        end

        %# call default close callback
        feval(@closereq)
    end
end

The code simulates running a lengthy processing step on a number of images, while at the same time showing an animation to keep the user entertained.

To keep the code simple, I am showing a patch that updates its color continuously (using a timer). This stands for the animated GIF image of "loading...".