Question

尝试在MATLAB图形中使用ButtonDownFcn时遇到问题。从这个意义上说，文档似乎有些矛盾，因此很难确切地理解我应该做什么。我想要做的是将函数分配给图中的线。当用户单击分配了该“ ButtonDownFcn”回调函数的任何给定行时，我的程序将同时获取该行对象和一个名为“ selectionObj”的变量，然后将该行对象复制到“ selectionObj”（这是专门编写的类），然后返回新版本的“ selectionObj”，以便用户可以继续选择更多行并组成选择集。具体来说，我的问题是正确地将输入和输出传递给此句柄，因为在这种情况下，我对如何使用语法感到不确定。

我将在下面附加一个MWE（最小工作示例），以便您可以重现我遇到的相同问题。我的问题特别是与此行：


    set(lineInPlot{i}, 'ButtonDownFcn', @(linehandle)mouseLineSelectMWE(linehandle), 'PickableParts', 'all')

特别是在“ @（linehandle）mouseLineSelectMWE（linehandle）”处

MATLAB文档说，通常，我可以使用以下形式的句柄

hand = @(s) s.^2 + 1;
result = hand(2); % Which produces result = 5.

但是，在这种情况下，我无法在此处指定左手参数。如果您想到的语言是C及其派生语言，通常这意味着您必须将指针传递到函数中。 MATLAB的方法是指定“全局”变量，该变量可以在任何地方被字面上调用，并且指向内存中的同一位置。因此，在MWE中，selectionObj是全局的，在mouseLineSelectMWE中将其作为全局调用。

此外，回到代码段@（linehandle）mouseLineSelectMWE（linehandle）”，我已经看到人们使用@（〜，〜）function，@function（aRandomVariableHere）等这些句柄，诸如此类那么，我不确定如何在此处指定输入和输出的精确度，尤其是当我需要将该精确的行传递到代码中时。

所以，归根结底，我真正需要修复的是（〜，〜）fun（）部分，我不太了解它的工作原理。

MWE：

close all % Clear current plots
clear all

global selectionObj
% selectionObj = BCselectionMWE; % Creation
selectionObj = BCselection; % Creation

%% Starting the BC selection figure
fig1 = figure(1);
ax1 = axes;
hold on

% Plotting lines
for i = 1:4
    lineInPlot{i} = plot3(...
        rand(2,1), ...
        rand(2,1), ...
        rand(2,1),...
        'Color',[.5 .5 .5],...
        'LineWidth',1.2...
        );

    linehandle = lineInPlot{i}; % Perhaps this is unnecessary
    set(lineInPlot{i}, 'ButtonDownFcn', @(linehandle)mouseLineSelectMWE(linehandle), 'PickableParts', 'all')

end

% Figure formatting
grid on
view([50 25])       % Initial POV ([45 30] is also good)
daspect([1 1 1])    % Constraints the data aspect ratio. The geometry won't 
                    % be distorted as you pan around.


%% Class
% 
% classdef BCselectionMWE
%     %BCSELECTION Summary of this class goes here
%     %   Detailed explanation goes here
%     
%     properties (SetAccess = private)
%         % Every clicked line will be, first, placed in 'kids'
%         kids    % ...'kids' because all the 'children' lines will be here
%     end
%     
%     methods
%         function obj = BCselection
%             %BCSELECTION Construct an instance of this class
%             %   This class creates objects that make easier the process of
%             %   organising the selected child lines, their created patches,
%             %   and the different BC groups created
%             
%             % We want all properties being created as empty cell arrays.
%             kids = cell(0,0);
%         end
%         
%         function obj = addLine(obj,lineChildren)
%             %ADDLINE This method adds a line to the current selection
%             
%             % Doing the stuff necessary if this is a line being added to
%             % the selection
%                 % Highlighting in blue the selected line
%                 lineChildren.Color(3) = 1;
%                 % Adding the kid to the kindergarten
%                 obj.kids{n+1} = lineChildren;
%         end
%     end
% end

%% Function for callbacks

function selectionObj = mouseLineSelectMWE(lineObj,~)
    %MOUSELINESELECT Passes the line object clicked to the addline command of
    %the BCselection class. Important since the output can be redirected to the
    %class, and not the line object itself.

    % THE GLOBAL VARIABLE selectionObj MUST EXIST! selectionObj is an instance
    % of the BCselection class
    global selectionObj

    % Adds (or removes) the line
    selectionObj = selectionObj.addLine(lineObj);
    % selectionObj.addLine(lineObj);
    % This is necessary since the output of the class function must still point
    % to the selectionObj variable

end

当前错误消息是：

*Error using lineSelectionMWE>@(linehandle)mouseLineSelectMWE(linehandle)
Too many input arguments.

Error while evaluating Line ButtonDownFcn.*

如何为MATLAB回调准确传递函数句柄？

0 个答案: