I'm trying to build a calculator. I have a listbox and a series of pushbuttons for the operations (+,-,/,sqrt,cos,sin.). I display what the user is clicking on an edit box. When the user clicks on 'cos' e.g., it only displays 'c'. Please check the co

function calculator(hObject,~,~) %Calculator
handles=guidata(hObject);
h=figure(...));
(...)
uicontrol('Parent',h,'Style','pushbutton','BackgroundColor','w','FontSize',11,...
    'FontWeight','bold','ForegroundColor','k','Units','Normalized','Position',[0.88,0.3667,0.0981,0.1],'String','cos','Callback',@expopup);
(...)
handles.calculator=h;
guidata(handles.calculator,handles);
%%%%%%
function expopup (hObject,~,~) %CALCULATOR visior printing;)
handles=guidata(hObject);
ed=findobj(handles.calculator.Children,'style','edit');
if hObject.Value==0
    list=hObject.String;
else
    list=hObject.String(hObject.Value);
end
txtstr=get(ed,'String');
txtstr=strcat(txtstr,list);
set(ed,'String',txtstr);

[Rik]

There isn't an obvious mistake that jumps out to me. Can you make this code into an MWE, which reproduces the problem in as few lines of code you can?

[susana]

Hello Rik, Thanks for your quick answer. Yes, please see the attached code. You should be able to run this. Hope you can help me. Best regards, Susana

Answer 1

[Greg]

The 'Value' property of a pushbutton uicontrol is set to 1 during callback execution. Therefore, your button vs. list logic:

if hObject.Value==0
    list=hObject.String;
else
    list=hObject.String(hObject.Value);
end

enters the "else" statement and chooses only the first character of hObject.String. Try looking at a property of hObject that is guaranteed to be listbox-specific ("style" maybe?).

[Walter Roberson]

Good catch.

This section of code looks to me as if it was written with popups or listbox in mind rather than push buttons. For popups and listbox, you would have logic similar to

if isempty(hObject.Value)
  list = '?? Nothing Selected ??';
else
  list = hObject.String{hObject.Value};
end

But for push buttons, you would just copy the entire String property without indexing

if hObject.Value==0
    list = '?? Button is up ??';
else
    list = hObject.String;
end

[susana]

Excellent catch. Thanks a lot. It solved my problem..