Block GUI in Callback
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Dear all,
how can I block interaction with a GUI, while a callback is executed. I'd like to create a GUI where by clicking a button a dialog to select a file opens and afterwards something is done to the file that is pretty time-consuming. Suprisingly, the callback is somehow executed in parallel, so it doesn't automatically block execution and this leads to undesired behaviour, because you could open the file-open-dialog again and I'd prefer to make this less annoying.
For illustration I created a small class:
classdef testGUI < handle
properties(Access = private)
hMainFigure
end
methods(Access = public)
function this = testGUI()
this.hMainFigure = figure('Visible', 'off');
uicontrol('Style', 'pushbutton', 'String', 'Test', 'Callback', @this.testCallback, 'Parent', this.hMainFigure, 'Units', 'normalized', 'Position', [0,0,1,1]);
this.hMainFigure.Visible = 'on';
end
end
methods(Access = private)
function testCallback(~, ~, ~)
% -- deactivate main figure
pause(2);
% -- activate main figure
fprintf('test\n');
end
end
end
If you click the button, the callback is executed and you can immediately click the button again - I would like to block the entire GUI until the callback (here the pause) is finished.
Thanks in advance,
Torsten
0 Comments
Accepted Answer
Geoff Hayes
on 23 Apr 2020
Torsten - you could disable the button so that it can't be pressed again
function testCallback(~, hButtonObj, ~)
% -- deactivate main figure
set(hButtonObj, 'Enable', 'off'); % <----- disable button
pause(2);
% -- activate main figure
fprintf('test\n');
set(hButtonObj, 'Enable', 'on'); % <----- enable button
end
Of course, if you have several buttons or fields, you would need to block all of them too. Or consider using a Indeterminate Progress Bar....I think it is modal so while it is present, the user shouldn't be able to interact with your GUI.
6 Comments
More Answers (1)
Rik
on 24 Apr 2020
Edited: Rik
on 24 Apr 2020
%appdata is the guidata struct (which I now think was a poor choice as a name)
ButtonCallbackBuzy=appdata.ButtonCallbackBuzy;
if ButtonCallbackBuzy
return%ignore key presses if a callback is already in progress
else
appdata.ButtonCallbackBuzy=true;
guidata(appdata.fig,appdata);
end
You do need to carefully keep track of when you load and save the guidata struct.
It might be a better idea to write a getter and setter function to do it:
%in your functions that need to check if the busy flag is set:
if getIfBusyFlag(gcbf)
return%ignore
else
setIfBusyFlag(gcbf,true)
end
%long running code
setIfBusyFlag(gcbf,false)
%getter and setter
function isBusy=getIfBusyFlag(hfig)
isBusy=false;
if ~isappdata(hfig,'isBusy')
setappdata(hfig,'isBusy',isBusy);
else
isBusy=getappdata(hfig,'isBusy');
end
end
function setIfBusyFlag(hfig,isBusy)
setappdata(hfig,'isBusy',isBusy);
end
3 Comments
Rik
on 28 Apr 2020
That is of course your call, although I doubt this will cause a lot of overhead. You could time how long these function take, but it is up to you to decide if that performance penalty is worth it.
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