waitbar cancel button does nothing!

So I have this bit of code where I make a waitbar at the start with a cancel button. There is a bit to stop it if the waitbar is pushed, but if I run it it doesn't work - the button is pushed but it doesn't stop the calculation. What am I doing wrong?? Is it something to do with the waitbar handle h? Before I had it as handles.waitbar, but the same thing happened! Please help me!

while get(t,'UserData') tic; %Start a stopwatch timer. TIC and TOC functions work together to measure elapsed time. h = waitbar((time /handles.PARAMS.time_max), sprintf('%3.2f', (time /handles.PARAMS.time_max * 100) ),'CreateCancelBtn','setappdata(gcbf,''canceling'',1)'); setappdata(h,'canceling',0);

    % does some stuff

    if getappdata(h,'canceling') % Cancel button has been pressed
        time = time + toc; % updating time duration of the calibration
        Statut = true; % Indicating how ends the calibration
        delete(h);
        break
    end

    % do other calculations, not using waitbar

    time = time + toc; % updating time duration of the calibration
    pause(0.01); % In order to escape the loop if we press the "cancel button"
    delete(h);
end

[Rebecca Vos]

but when I put "setappdata(h,'canceling');" before the loop it cancels it fine... so don't know what is happening here

Answer 1

[Sean de Wolski]

gcbf

Is very dangerous and should be avoided all of the time. It could be a figure, it could be a button, axes etc, who knows! In general for an applicatiom, all of the g* functions should be avoided (gcf, gca, gco etc.) because they're dynamic.

Instead, hardwire the handle to the object whose appdata is being referenced:

fig = figure
setappdata(fig,'cancelling',false)

etc.

[Rebecca Vos]

but it's not a figure, if I do that it just creates a blank figure? Sorry I'm not very good at this...

[Sean de Wolski]

This line probably does nothing

setappdata(gcbf,''canceling'',1);

This one does because h doesn't change

setappdata(h,'canceling',0);

use a variable for whatever you want gcbf to be referencing in the first setappdata and use it (probably h again?).