How to set the default value for Edit Text in GUI ? If not input a number , I hope the contents auto changed to be '5'

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Lisa Wu
Lisa Wu 2012-11-19
In the function edit1_callback(),it is writed as :
edit1 = str2double(get(hObject,'string'));
if isempty(edit1)
edit1 = 5; % when not input a number ,the contents is 5;
end
handles.edit1 = edit1;
guidata(gcbo,handles);
As a matter of fact,when I do not input a number,the edit text contents is not 5,Why?
And ,how can I set the default value of edit text??
Thank you for your attention!

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采纳的回答

Teja Muppirala
Teja Muppirala 2012-11-19
STR2DOUBLE returns NaN for non-numeric data. Instead of checking for empty input using ISEMPTY, use ISNAN instead.
if isnan(edit1)
set(handles.edit1,'string','5');
end
  2 个评论
Lisa Wu
Lisa Wu 2012-11-19
编辑：Lisa Wu 2012-11-19
As you said: function edit1_callback() edit1 = str2double(get(hObject,'string')); if isnan(edit1) set(handles.edit1,'string','5'); end guidata(gcbo,handles);
funciton pushbutton1_callback() x = handles.edit1; y = x+7; plot(x,y,'*r'); guidata(gcbo,handles);
When run it ,the default value of x is not 5 ,i'm puzzled. Thank you !
Arthur
Arthur 2012-11-19
You forgot to store edit1. And, I think it's better to retrieve the value of handles.edit1 in the pushbutton callback. Try this:
function edit1_callback()
edit1 = str2double(get(hObject,'string'));
if isnan(edit1)
set(handles.edit1,'string','5');
end
function pushbutton1_callback()
x = str2double(get(handles.edit1,'String'));
y = x+7;
plot(x,y,'*r');

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