Help to use Callback property in uicontrol
显示 更早的评论
Hi,
I don't understand how works the 'Callback' property in uicontrol. For example, I create a pushbutton as
pb = uicontrol('Style', 'pushbutton', 'Callback', @fun);
as callback function I need simply an increment of a variable "i" initially i=0; in other words when I click in the pushbutton it should cause increment of "i" by one.
I tried with:
function fun(in)
in=in+1;
end
and so...
pb = uicontrol('Style', 'pushbutton', 'Callback', {@fun, i});
but it doesn't work. Some suggestions ?
Thanks
采纳的回答
Matt Fig
2012-11-3
Where is the variable stored? Callback functions take at least 2 inputs, always. Here is a simple demo, illustrating one way to do what you want. Note that I have made it step by step so you can take the semicolons off to see what is going on in the callback if needed.
function [] = demo_cb()
S.fh = figure('units','pixels',...
'position',[300 300 300 130],...
'menubar','none',...
'name','demo_cb',...
'numbertitle','off',...
'resize','off');
S.pb = uicontrol('style','push',...
'unit','pix',...
'position',[10 20 280 90],...
'string','I=1',...
'fontsize',14,...
'callback',@pb_call);
function [] = pb_call(H,E)
% Callback for pushbutton.
Str = get(H,'string');
Num = regexp(Str,'=','split');
NewNum = str2double(Num{2})+1;
set(H,'string',sprintf('I=%i',NewNum))
7 个评论
Marco
2012-11-3
Like I said, all callbacks take at least two input arguments. The first one is the handle to the calling object, the second one is an eventdata structure that is seldom used. If you want to learn more about GUI making through examples like this, Check out this link:
Also, if your question has been answered, please select the answer.
Marco
2012-11-3
Walter Roberson
2012-11-3
There are very few types of callbacks that can return a value to the caller. You will need to use a different mechanism.
Marco
2012-11-3
Walter Roberson
2012-11-3
In Matt's example the callback function is not nested.
Sorry, I stepped away for a while. Walter is correct. The callback is a subfunction (or local function), not a nested function. I usually write GUIs with nested functions when I write them professionally, but using subfunctions is how most people first learn and in some cases it is simpler/preferred.
You can tell at a glance that there are no nested functions in that code because there are no END statements....
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 App Building 的更多信息
产品
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
