Writing Callback For GUI

Hello Everyone ! I am experiencing a problem while writing callback for pushbutton in GUI. The problem is that the function that ,is calculated in the callback , is represented by other 5-6 functions ,which also depend on user inputs ( also from GUI) . I would be extremely grateful if anyone could give a piece of advice on how to implement it in Matlab. Thanks in advance! Best Regards

[Jarrod Rivituso]

Are you getting any errors when trying to call these other functions from within your callback? If so, are the other functions in separate MATLAB files? Are they on your MATLAB path?

[Dimitry]

Hi !

If i put these functions in pushbutton callback , the pushbutton simply does not work. I tried to place them separately in the callback , then I got mistake since matlab was not able to obtain input values for the functions.I have all functions in separate files in Matlab path. The program works perfectly when I just put some fixed values for the parameters user should input, so I just wonder how one can make matlab read the input values send them to functions. Because,as said before all function depend pretty much on the same values.

Regards

Answer 1

[Dimitry]

Hi again ! I tried to use function assignin and getappdata to send handles value to the my own function Funk, which is stored in separate matlab file. However, the problem is that Matlab does not recognize the handles I am referring to . Every time , I get the following message :

??? Undefined variable "handles" or class "handles.iter".

Error in ==> Funk at 2 M1=getappdata(handles.iter)

Error in ==> thesisgui>pushbuttonKim_Callback at 280 while (abs(Funk(u,n))>eps) && (w>1) && (n>1)

I wonder if someone could give a piece of advice on this one. I am really stuck with it (=

[Walter Roberson]

The first parameter to getappdata() must be the handle of the object to retrieve the data from. Unfortunately for you, you do not pass an object handle down to that routine. You might, however, be able to refer to the pushbutton by calling gcbo

M1=getappdata(gcbo, handles.iter)

But! The second parameter to getappdata() needs to be the item *name*, and handles.iter is not an item *name* (especially with it being undefined.)

I would suggest,

handles = guidata(gcbo);

I suspect you will find that you do not need to use getappdata or assignin .

[Dimitry]

Thank you very much Walter Roberson !!!=) Now it works perfectly , I did not even need to use getappdata , it was enough with ´handles = guidata(gcbo) and then with simply get.

Answer 2

[Matt Fig]

Where would you get the values for the functions? If you are wanting to get them from other uicontrols (editboxes, for example), then you must query the correct property of the uicontrols from within the pushbutton callback.

Tell where you would like to get the inputs to the separate functions...

[Dimitry]

Thank you for your answer. I need to get the inputs from editboxes .I wonder if you could explain which commands I need to implement in pushbutton's callback in order to succeed with this task .Another thing that is really puzzling me is where I should have the functions in separate files or in some part of the GUI callback.

Thanks in advance !

Regards

[Matt Fig]

In the callback to the pushbutton, you simply query the 'string' property of the editboxes. If you are expecting numeric values, remember to convert them first.

N1 = str2double(get(editbox1handle,'string'));

N2 = str2double(get(editbox2handle,'string'));

N3 = str2double(get(editbox3handle,'string'));

...etc

The handles to the editboxes can be obtained through the handles structure, or by calling GUIDATA or GUIHANDLES.

[Dimitry]

Hi !

Thank you for your advice. I implemented but I still got the same error. I wonder where I should place the functions that depend on these variables and the function that is executed in the callback also depends on them .

Thanks in advance for your help

[Matt Fig]

The more information I have, the better I can help you. So:

WHAT ERROR?

Please show the entire error message!

Also, what do you mean "the function that also depends on them?" You need to be a lot clearer in what you are trying to do. It was my understanding that you had several M-file functions in different files which you wanted to run when a pushbutton was pressed. Further, the arguments to these function M-files were to be taken from the editboxes in the GUI. So they are the functions that depend on these values, so what do you mean by "function that is executed in the callback also depends on them . "

Please, if you want help, be VERY clear about what is supposed to happen when the button is pushed.

Answer 3

[Dimitry]

Thank you for your answer. I need to get the inputs from editboxes .I wonder if you could explain which commands I need to implement in pushbutton's callback in order to succeed with this task .Another thing that is really puzzling me is where I should have the functions in separate files or in some part of the GUI callback. Thanks in advance ! Regards

Answer 4

[Dimitry]

Sorry that I was not perfectly clear. I have the following code which I want to execute when the pushbutton is pressed :

w=M;
n=M;
u=ones(M,1)
delT=T/M;
eps=0.000000001;
u(w)=(K*min(1,r/delta));
while (abs(Funk(u,n))>eps) && (w>1) && (n>1)
 u(w-1)=u(w)-(Funk(u,n)/Funkder(u,n));

           n=n-1;
           w=w-1;
  end
  u
  u0=u(1)-(Funk(u,1))/(Funkder(u,1))
  if (u0>S0 || u0==S0)
      price=K-S0
  else
      for h=M:-1:3
          summe(h)=(delT)/3*(2*f1(S0,u(h-2),(h-2)*delT) +4*f1(S0,u(h-1),(h-1)*delT)+f1(S0,u(h),h*delT));
      end
      summe1=sum(summe);
      price=K*exp(-r*T)*normcdf(-(log(S0/K)+(r-delta-(sigma^0.5)/2)*T)/(sigma*T^0.5))-S0*exp(-sigma*T)*normcdf(-(log(S0/K)+(r-delta+(sigma^0.5)/2)*T)/(sigma*T^0.5))+(delT/3)*(f1(S0,u0,0)+4*f1(S0,u(1),delT)+2*f1(S0,u(2),2*delT))+summe1
  end

As you can see, I have a number of functions ( Funk;Funkder and others ) which depend on values like K,T,M,S0 and so on that is entered by user in the editboxes. Here is for example code for Funk:

x(M)=(K*min(1,r/delta));
i=y1;
if i==M
    summa1=0;
    o=x(M)-K+0.5*(r*K-delta*x(M));
else
if (i+1)<(M-1) 
   for j=(i+1):1:(M-1)
        fsum(j)=delT.*f1(x1(i),x1(j),(j-i)*delT);

     end
     summa1=sum(fsum);
     o=x1(i)-K+p1(x1(i),K,(M-i)*delT)+0.5*delT*(f1(x1(i),x(M),(M-i)*delT)+0.5*(r*K-delta*x1(i)))+summa1;
          else
                   summa1=0;
      o=x1(i)-K+p1(x1(i),K,(M-i)*delT)+0.5*delT*(f1(x1(i),x(M),(M-i)*delT)+0.5*(r*K-delta*x1(i)))+summa1;
  end
  end
   if~nargout; 
      o;
      end

As you can see , Funk depends on the parameters that user enters from the keyboard. I have several following function that require those inputs. I am puzzled with first where I should have all those functions (like Funk ,Funkder and so on ) as well as how should send inputs to them . I have tried to have all such functions in the pushbutton callback before that piece of the code that responds for the calculations. In that case, I was getting no error message , but Matlab simply would get stuck . Then I tried to put those function outside pushbutton callback when then it seems like Matlab only can see the inputs from the editboxes just in pushbutton callback while I ,for example, get an error in the Funk that K is unknown variable because Matlab says "Undefined variable "handles" or class "handles.stock". I am very grateful that you are trying to help me and I hope I have explained my problem better this time. Best Regards

[Oleg Komarov]

I suggest to give a look at http://www.mathworks.com/matlabcentral/fileexchange/24861-41-complete-gui-examples

[Dimitry]

Thanks a lot !

Gonna check the link and hopefully it will solve my problem.

Regards