How to read a value of popup inside its callback

Question

Michal 2014-7-13

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/141684-how-to-read-a-value-of-popup-inside-its-callback

回答： Michal 2014-7-13

Hello,

I am currently working on a GUI and got stacked at some point. I want to read the value of selected popup element inside its callback to change value of some other GUI component. Below the code that attempts to display the selected element

S.FromBlockPopUp = uicontrol('Style', 'popup',...
    'String', ' ',...
    'fontsize',10,...
    'position',[400 200 100 25],...
    'callback',{@update_text,S});
function [] = update_text(varargin)
S = varargin{3};  % Get the structure.
disp(getCurrentPopupString(S.FromBlockPopUp))
function str = getCurrentPopupString(hh)
list = get(hh,'String');
val = get(hh,'Value');
if iscell(list)
   str = list{val};
else
   str = list(val,:);
end
After execution I got the error:
Undefined variable "S" or class "S.FromBlockPopUp".

Unfortunately I am not able to read selected value as the struct S does not have a handle to that popup (It was created while adding the callback, hence the callback can't access it).

It seems a bit weird that I can't read it. Do you have any suggestion how it can be solved? Do you know any workarounds?

BR, Michal

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Michal 2014-7-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/141684-how-to-read-a-value-of-popup-inside-its-callback#answer_144936

在 MATLAB Online 中打开

Solved:

S.FromBlockPopUp = uicontrol('Style', 'popup',...
    'String', ' ',...
    'fontsize',10,...
    'position',[400 200 100 25]);
set(S.FromBlockPopUp,'callback',{@update_text,S});

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Ben11 2014-7-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/141684-how-to-read-a-value-of-popup-inside-its-callback#answer_144933

编辑：Ben11 2014-7-13

在 MATLAB Online 中打开

Maybe using setappdata and getappdata? You could store your structure and retrieve it among the callbacks of your GUI.

eg.

setappdata(HandlestoYourGUI,'S',S);

at the end of a callback

and then

S = getappdata(HandlestoYourGUI,'S');

at the beginning of another in which you need to use s.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 3

Image Analyst 2014-7-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/141684-how-to-read-a-value-of-popup-inside-its-callback#answer_144934

在 MATLAB Online 中打开

You can use GUIDE. Then it's trivial -- in the popup callback (or anywhere else that you have access to handles, like other callback functions) just do:

selectedItem = get(handles.popup1, 'Value'); % The item number that is selected.
allTextItems = get(handles.popup1, 'String'); % A list of the strings in the popup
selectedText = allTextItems{selectedItem}; % Text of whatever item number they selected.

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Image Analyst 2014-7-13

It's definitely a lot harder if you're going to "roll your own" and take care of all those nitty gritty details yourself, as you found out. But if you're one of those who insist on doing it the hard way, see the FAQ: http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.28s.29.3F Good luck.

请先登录，再进行评论。