MATLAB Answers

Sara Marques

Slider in GUI

Asked by Sara Marques
on 19 Aug 2011


I'm having trouble getting a slider to work in a GUI.

I currently have 1 slider in my GUI, that is suposed to change its values everytime a different variable is chosen in a popupmenu.

After a certain variable is chosen, the slider Min and Max properties would be changed to the variable Min and Max and the slider should run through all the variable values.

I've tried to change the slider Min, Max and Step properties by writing


but its not working.

Is it possible to make the slider work this way? And if it is, how can i do it?

Thanks in advance.





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2 Answers

Answer by Paulo Silva
on 19 Aug 2011
 Accepted answer

not working? how can we help if you don't provide enough details (error message at least), please be sure that variablemax and min are numbers (use str2num if it's a string) not strings or a cell. Also remeber to update the handles structure after setting the new values.

prompt = {'Enter min:','Enter max:'};
dlg_title = 'min=?,max=?';
num_lines = 1;
def = {'0','1'};
answer = inputdlg(prompt,dlg_title,num_lines,def);
%answer is a cell with two strings
%You must choose the cell element answer{n} , that gives you the string
%first one is the min and the second is the max
%Now you need to convert string to number, that can be done using str2num
% Update handles structure
guidata(hObject, handles);


Answer by Sara Marques
on 19 Aug 2011

Hello Paulo

Thanks for the quick reply.

Heres the code I wrote to try to get the slider working as intended:

function popupmenu5_Callback(hObject, eventdata, handles)
% hObject    handle to popupmenu5 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% Hints: contents = cellstr(get(hObject,'String')) returns popupmenu5 contents as cell array
%        contents{get(hObject,'Value')} returns selected item from popupmenu5

When i choose a variable listed in the popupmenu, the code gets the correspondent variable row in the input matrix. I get the warning:

Warning: slider control can not have a Value outside of Min/Max range
Control will not be rendered until all of its parameter values are valid 

Im new in developing GUIs, so I dunno what im doing wrong.

Thanks in advance



Paulo Silva
on 19 Aug 2011

When you set a value for the slider that is outside of its limits max and min that slider give the error and is invisible, always set a value inside the limits.

Sara Marques
on 19 Aug 2011

hello again

You're right Paulo. I wasn't updating the slider value. Works fine now.

Thanks a lot for the help


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