How to get a push button to end a loop in a GUI?

I have created a GUI using GUIDE. The purpose is to plot an animation of a very simple projectile motion equation. I have edit text fields to enter the initial angle and velocity, drop downs to select the units, and two push buttons, one to plot and one to stop. Everything works well except for the stop button. I cannot seem to get it to interrupt the loop. I unchecked the interruptible box in the editor for the plot button. I don't have a very good grasp on the callback functions or hObjects or handles, and I would like a simple resolution. Can someone give me an idea of what I am doing wrong in the code below?

stop=get(handles.pushbutton4,'Value')
if stop==1
break;
end

This is homework, but adding stop functionality is not part of the assignment, this is just something I would like to do. We are only required to create a simple GUI; the animation is not even necessary.

Answer 1

[Ingrid]

you need to set a flag when you press the pusbutton to stop so in your pushbutton4 callback you should put this instead of the code you have there now:

   setappdata(handles.figure1,'stopPlot',1);
   % Update handles structure
   guidata(hObject, handles);

then in the for loop you should put this

   if isappdata(handles.figure1,'stopPlot')
        break
   end

to be able to rerun your animation you should also put this after your for-loop

   rmappdata(handles.figure1,'stopPlot')

You also need to set the Interruptibility of pushbutton1 to on (change this in guide)

it also seems that you are missing a call to

drawnow

right before the end of your for-loop because otherwise you do not see your animation move

and finally may I ask why you do not use a semi-colon to surpriss output being shown in the command window?

[Ingrid]

glad to see it worked

one more comment however, you should also remove the keypressfunction in your fig file for pushbutton4 since this is not implemented in your m-file and gives error-message when the pushbutton is still selected and you are doing stuff on the keyboard in the meanwhile

and one really final comment: I think your legend should be changed i.e. 'Position of Object','Path of Object','Maximum Height' instead of 'Path of Object','Position of Object','Maximum Height' as it is currently implemnted in your code

by the way, cool homework!

[zeytun]

Hi Ingrid. Thanks for your answer, it helped me too to stop the "for" loop in my GUI (which is a measurement from a real device and plotting the result). However, I have one question. During the loop, when I am applying the "Stop" button, everything is fine: it finishes the current measurement and plots the result. Now, if I don't apply the "Stop" button and wait until the loop is done on its own, it still plots the final result but gives the following error:

Error using rmappdata

Invalid user property: stopPlot

The part in the m-file responsible for stopping the loop is as follows:

for K = 1:handles.kk

...

axes(handles.axes11); % plot current result inside the loop

cla reset;

plot(K1(1:K),T1(1:K),'o -')

drawnow

if isappdata(handles.axes11,'stopPlot')

   break
end

end

figure(1); % plot final result outside the loop

plot(K1,T1,'o -')

rmappdata(handles.axes11,'stopPlot')

...

% --- Executes on button press in stop.

function stop_Callback(hObject, eventdata, handles)

% hObject handle to stop (see GCBO)

% eventdata reserved - to be defined in a future version of MATLAB

% handles structure with handles and user data (see GUIDATA)

setappdata(handles.axes11,'stopPlot',1);

% Update handles structure

guidata(hObject, handles);

end

Can you please help me to resolve this issue?

Thanks, Aram