How to stop a while loop using a GUI pushbutton?
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I have a while loop and I have a STOP pushbutton that breaks the loop. Basically I want to break the loop using the pushbutton instead of typing CTRL+C on command window. I tried the return clause but it didn't work and the break clause aparently it's used inside the loop (which isn't the case).
Can anyone help me?
Thanks!
回答（6 个）
Walter Roberson
2013-11-13
while true
drawnow()
stop_state = get(YourPushbuttonHandle, 'Value');
if stop_state
break;
end
...
end
7 个评论
Flávio
2013-11-13
ZacksHacks
2014-6-12
编辑：ZacksHacks
2014-6-12
Some people might find it crude, but you can just use a global variable if you are not familiar with GUI syntax and just want a quick fix.
%Button 1 Click
global true;
true = 1;
while true == 1
drawnow()
%Your loop code here
end
%Stop Button Click
global true;
true = 0;
Vibhor Gulati
2016-5-26
Oh you saviour! Nothing else seemed to work for me.
Jannis
2018-6-29
Super helpful, also works in appdesign.
Stephen23
2018-6-29
It is recommended to avoid slow and buggy global variables:
Image Analyst
2018-6-29
App Designer has a different way of using global variables I believe - you don't use the global keyword.
Stephen23
2018-6-29
@Image Analyst: I have never used App Designer, but as far as I can tell it creates some kind of objects, whose properties are available throughout the app:
https://www.mathworks.com/help/matlab/creating_guis/share-data-across-callbacks-in-app-designer.html
What does this have to do with global variables?
Image Analyst
2018-6-29
4 个投票
See my attached little demo. It counts when you click the Go button and stops counting when you click the Stop button.
5 个评论
Liza Vörös
2020-3-23
It does not work
Liza Vörös
2020-3-23
I get this error:
Dot indexing is not supported for variables of this type.
Error in gostop>btnStop_Callback (line 103)
set(handles.btnStop,'userdata',1)
Error in gui_mainfcn (line 95)
feval(varargin{:});
Error in gostop (line 45)
gui_mainfcn(gui_State, varargin{:});
Error in
matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)gostop('btnStop_Callback',hObject,eventdata,guidata(hObject))
Error while evaluating UIControl Callback.
Dot indexing is not supported for variables of this type.
Error in gostop>btnGo_Callback (line 84)
set(handles.btnStop, 'userdata', 0);
Error in gui_mainfcn (line 95)
feval(varargin{:});
Error in gostop (line 45)
gui_mainfcn(gui_State, varargin{:});
Error in
matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)gostop('btnGo_Callback',hObject,eventdata,guidata(hObject))
Error while evaluating UIControl Callback.
Image Analyst
2020-3-23
I just downloaded it again and it works fine. When it says "Dot indexing is not supported" for the handles variable, it indicates to me that somehow your handles structure got corrupted. Did you modify my file at all? Like put a clear statement in there somewhere? Please attach your exact files and I'll download and run your version.
Haotian Xue
2021-3-16
It works great, thank you so much.
aung lin
2022-7-12
Thank You very much Sir!
Birkan GOCERLER
2014-9-21
3 个投票
Andrew Davies
2015-9-15
The solution to the problem can be found here http://stackoverflow.com/questions/4522447/breaking-from-for-loop-in-matlab-gui
the basic outline could look like this:
For the callback of the start push button you want something like this.
functionpushbutton1_Callback(hObject, eventdata, handles)
handles.stop_now = 0; %Create stop_now in the handles structure
guidata(hObject,handles); %Update the GUI data
while ~(handles.stop_now)
yourfunction()
drawnow %Give the button callback a chance to interrupt the %opening fucntion
handles = guidata(hObject); %Get the newest GUI data
end
In the callback for the stop button you want
function pushbutton2_Callback(hObject, eventdata, handles)
handles.stop_now = 1;
guidata(hObject, handles); % Update handles structure
Essentially of the these solutions are based on the same ideas. Another approach (that uses the same idea) is to use the MATLAB inbuilt waitbar() function, which supports canceling a loop and details how to do in the documentation... FOUND HERE. This way you don't have to explicitly program the canceling functionality of your button 2, which is useful if you are still getting to grips with GUIs.
Edit: And only after answering do I realize this is a somewhat old thread!
Seo-Hyun
2017-4-12
I used a toggle button for pause, and added the pause code in the loop. While pausing, you can always grab a breakpoint in the paused line and continue debug. Try this.
while(1)
if handles.pause.Value
pause(1);
handles.pause.String = 'Resume';
disp('waiting');
while ~handles.pause.Value
handles.pause.String = 'Pause';
break;
end
continue;
end
end
function pause_Callback(hObject, eventdata, handles)
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