How can pause/stop/resume/run Matlab gui code?

I have developed a code for run/pause the code which is palying a song and plotting a figure. However, inside my while 1, the result of button4 is not update. Where is my fault?

function pushbutton1_Callback(hObject, eventdata, handles)
set(handles.pushbutton4, 'userdata', 1);
while 1
    a= get(handles.pushbutton4, 'userdata') 
    if a==0
        disp('break');
    break;
    else
    disp('inside loop');    
    end
end

function pushbutton4_Callback(hObject, eventdata, handles)
if get(handles.pushbutton4,'userdata')==1
set(handles.pushbutton4,'userdata',0);
else
set(handles.pushbutton4,'userdata',1);
end

[Jan]

By the way: You can simplify the callback:

function pushbutton4_Callback(hObject, eventdata, handles)
handles.pushbutton4.UserData = ~handles.pushbutton4.UserData;

[Hassan Bosha]

What is the user data ?

should it be written like this ?

function Resume_Callback(hObject, eventdata, handles)

handles.Resume.UserData = ~handles.Resume.UserData;

Answer 1

[Jan]

You cannot directly stop Matlab code by a GUI. Note that the callback of the GUI would be stopped also.

You can control the execution of a loop through a GUI, if you request e.g. the UserData of a certain button, which is toggled in its callback.

What is the actual problem you want to solve?

[EDITED] Give the figure a chance to update its properties by inserting drawnow:

   while 1
     drawnow;
     a = get(handles.pushbutton4, 'userdata');
     ...

[amir nemat]

Please see the updated question

[Jan]

See [EDITED]

[Luis Cavalcante Fraga]

Thanks for your help, Jan ! This is the second time you save my app.

Answer 2

[Image Analyst]

See attached demo.

[amir nemat]

please see the updated question

[Image Analyst]

You need to call guidata().

Answer 3

[Akhilesh Thakur]

function pushbutton1_Callback(hObject, eventdata, handles)

set(handles.pushbutton4, 'userdata', 1);

This set(handles.pushbutton4, 'userdata', 1); is wrong. Because you are writing handles.pushbutton4 in the callback of pushbutton1. You are missing guidata(hObject,handles) in your pushbutton4 callback. This will update your handles structure and it will work.

[Akhilesh Thakur]

This won't work unless you add guidata(hObject,handles). This should make your program work.

Hope this helps

[Image Analyst]

I had already suggest this, and we're waiting to hear back.

[Eric Keller]

I use getappdata/setappdata for semaphores. guidata just seems too complex and almost surely uses the same mechanism. You can have as many named appdata structures as you want.

[Image Analyst]

That would work too. Both getappdata/setappdata and guidata are just one line of code.

[Jan]

I do not think that guidata or setappdata help here. The OP did not change the handles struct, but used it to set the UserData of the button. Then only drawnow is missing to allow an update of the properties.

[Image Analyst]

Isn't the UserData a property of the button and thus stored in the handles structure along with all the other properties of the button? And if you change handles, like a field of it or adding a new field, those changes are local and vanish once the function exists unless you call guidata, or pass handles out as a return argument if the function is a custom function rather than a callback function of a control.

And I thought drawnow just repaints the screen which will just show the same screen unless some property of the control which is visible had been changed.