Matlab匿名回调函数参数(Matlab anonymous callback function arguments)

 按照Matlab中的模型视图控制器GUI示例，我有一个关于匿名函数回调输入参数的问题 
 
 这是一个视图函数，它创建gui句柄并将它们作为输入参数传递给onChanged回调函数。 
 
function handles = View_TimeDomain(m)
    %VIEW  a GUI representation of the signal model

    % build the GUI
    handles = initGUI();
    onChangedF(handles, m);    % populate with initial values

    % observe on model changes and update view accordingly
    % (tie listener to model object lifecycle)
    addlistener(m, 'f', 'PostSet', ...
        @(o,e) onChangedF(handles,e.AffectedObject));
end
 
 我不太明白的第一件事是，根据Matlab文档，第一个参数必须是事件的来源，第二个文件必须是事件数据（ Matlab doc1 ， Matlab doc2 ），但在这种情况下它是handles 。 触发事件时，将按预期调用以下onChangedF函数。 
 
function onChangedF(handles, model)
    % respond to model changes by updating view
    if ~ishghandle(handles.fig), return, end
    set(handles.line, 'XData',model.t, 'YData',model.data)
    set(handles.slider, 'Value',model.f);
end
 
 但是，在这种情况下，handle是包含使用initGui（）定义的句柄的结构，而不是事件源。 
 
 我想这源于匿名函数的定义： 
 
@(o,e) onChangedF(handles, e.AffectedObject)
 
 我是否正确，假设o是onChangedF函数输入中未使用的源。 有人可以解释为什么匿名函数的这种语法有效吗？ 我认为o需要成为这个特定回调函数的参数。 像这样的东西： 
 
@(o,e) onChangedF(o, handles, e.AffectedObject)
 
 其他参数附加（在函数的末尾）。 然后使用〜来避免这个未使用的参数： 
 
function onChangedF(~, handles, model)
    % respond to model changes by updating view
    if ~ishghandle(handles.fig), return, end
    set(handles.line, 'XData',model.t, 'YData',model.data)
    set(handles.slider, 'Value',model.f);
end

Following this example of a Model View Controller GUI in Matlab, I have a question regarding the anonymous function callback input arguments
 
Here is the a view function that creates the gui handles and passes them as an input argument to the onChanged callback function.
 
function handles = View_TimeDomain(m)
    %VIEW  a GUI representation of the signal model

    % build the GUI
    handles = initGUI();
    onChangedF(handles, m);    % populate with initial values

    % observe on model changes and update view accordingly
    % (tie listener to model object lifecycle)
    addlistener(m, 'f', 'PostSet', ...
        @(o,e) onChangedF(handles,e.AffectedObject));
end
 
The first thing that I don't quite understand is that according to the Matlab documentation the first argument must be the source of the event and the second arument must be the event data (Matlab doc1, Matlab doc2) but in this case it is handles. When the event is triggered, the following onChangedF function is called as expected.
 
function onChangedF(handles, model)
    % respond to model changes by updating view
    if ~ishghandle(handles.fig), return, end
    set(handles.line, 'XData',model.t, 'YData',model.data)
    set(handles.slider, 'Value',model.f);
end
 
However, in this case handles is the struct containing the handles defined using initGui() and not the event source.
 
I guess this stems from the definition of the anonymous function:
 
@(o,e) onChangedF(handles, e.AffectedObject)
 
Am I correct, assuming that o is the source which is not used in the onChangedF function input. Can someone explain why this syntax of an anonymous function is valid? I thought that o needs to be an argument of this specific callback function as well. Something like this:
 
@(o,e) onChangedF(o, handles, e.AffectedObject)
 
where additional arguments are appended (at the end) of the function. And then just avoid this unused argument using ~:
 
function onChangedF(~, handles, model)
    % respond to model changes by updating view
    if ~ishghandle(handles.fig), return, end
    set(handles.line, 'XData',model.t, 'YData',model.data)
    set(handles.slider, 'Value',model.f);
end

原文：https://stackoverflow.com/questions/45299016