GUI data Update

Question

Gerd 2011-3-8

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2707-gui-data-update

Hi guys,

I'm building a gui in matlab and have a question about the guidata update. I want to let the user change a value on a "Edit Text" control and this value changes the current plot function. I wait until the 'return' key is pressed and process the data. The problem is that the user has to hit the return key twice to change the value. I think the guidata is not updated. Does anyone has an advice? Gerd

 function txt_Faktor_KeyPressFcn(hObject, eventdata, handles)
% hObject    handle to txt_Faktor (see GCBO)
% eventdata  structure with the following fields (see UICONTROL)
%  Key: name of the key that was pressed, in lower case
%  Character: character interpretation of the key(s) that was pressed
%  Modifier: name(s) of the modifier key(s) (i.e., control, shift) pressed
% handles    structure with handles and user data (see GUIDATA)
if strcmp(eventdata.Key,'return')
    handles.Faktor = str2double(get(handles.txt_Faktor,'String'));
    % store variable
    guidata(hObject,handles);
    plotMainWindow(hObject, eventdata, handles);
end

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Answer 1

Walter Roberson 2011-3-8

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https://ww2.mathworks.cn/matlabcentral/answers/2707-gui-data-update#answer_4217

Why are you doing things that way instead of just using a callback function on the edit uicontrol ?

Note by the way, that you should be taking precautions in case the user entered something other than a number.

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Walter Roberson 2011-3-8

If you set

uicontrol('Style','edit', 'Callback', @txt_Faktor_Fcn)

then the callback will only be activated if "whenever you activate the uicontrol object (e.g., when you click on a push button or move a slider)" In the case of an edit callback, that occurs when you press return on the control, and does NOT occur if you type into the control but then click outside of the control.

Gerd 2011-3-8