Question

我正在尝试创建一个与MATLAB 2017b中的Line对象的类相似的类，但析构函数有问题。我想与其他图形对象实现类似的行为，即删除该句柄时不再引用该对象，如以下示例所示：

 >> l1 = line([0 1], [0 1]);

如果现在关闭了包含行l1的图形，则该变量表明l1引用了已删除的对象：

>> l1

l1 = 

  handle to deleted Line

我创建了以下课程：

classdef circle < handle ...
        & matlab.mixin.CustomDisplay & matlab.mixin.SetGet

    properties
        Center = [];
        Color = [0 0.4470 0.7410];
        Radius = [];
    end

    properties (SetAccess = 'protected')
        LineHandle = [];
    end

    methods
        function obj = circle(radius, center, varargin)
            if nargin > 0
                % assign property values
                obj.Radius = radius;
                obj.Center = center;

                % generate plotting variables
                phi = linspace(0, 2*pi, 90);
                x = radius*cos(phi) + center(1);
                y = radius*sin(phi) + center(2);

                % draw circle
                obj.LineHandle = line(x, y);

                % create listeners in line object
                obj.createListener;

                % set variable properties
                for k = 1:2:length(varargin)
                    % set superclass properties
                    if (isprop(obj.LineHandle, varargin{k}))
                        set(obj.LineHandle, varargin{k},varargin{k+1});
                        if (isprop(obj, varargin{k}))
                            set(obj, varargin{k}, varargin{k+1});
                        end
                    end        
                end
            end
        end

        % listener to invoke delete if line is closed
        function createListener(obj)         
            set(obj.LineHandle,'DeleteFcn',...
                @obj.delete);
        end

         function delete(obj,varargin)
            disp('deleted')
            %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
            % command to delete class ???
            %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
         end

    end

end

如果关闭了包含圆形对象的图形，则删除线，但圆形对象仍然存在。有没有办法删除对圆对象的引用？

Answer 1

我自己找到了答案。该函数只需要使用与delete不同的名称即可：

function delete_obj(obj, varargin)
        % delete handle
        delete(obj)
end

删除图形基元的MATLAB子类

1 个答案: