绘制2个图形时出现“无效的句柄对象”

[poster]

与C ++相比，我很难理解Matlab类的范例。前几天我写了代码，我认为它应该可以工作。直到我添加才开始

set错误无效的句柄对象。

==> Simulation> simulation.animate在设置45时发生错误（l.lm，'XData'，obj.landmarks.apparentPositions（：，1），'YData'，obj.landmarks.apparentPositions（：，2））;

%INITIALIZE GLOBALS global DATA XX XX = [obj.robot.x ; obj.robot.y]; DATA.i=1; DATA.path = XX; %Setup Plots fig=figure; xlabel('meters'), ylabel('meters') set(fig, 'name', 'Phil''s AWESOME 80''s Robot Simulator') xymax = obj.landmarks.mapSize*3; xymin = -(obj.landmarks.mapSize*3); l.lm=scatter([0],[0],'b+'); %"UNCOMMENT ME"l.pth= plot(0,0,'k.','markersize',2,'erasemode','background'); % vehicle path axis([xymin xymax xymin xymax]); %Simulation Loop for n = 1:720, %Calculate and Set Heading/Location XX = [obj.robot.x;obj.robot.y]; store_data(XX); if n == 120, DATA.path end %Update Position headingChange = navigate(n); obj.robot.updatePosition(headingChange); obj.landmarks.updatePerspective(obj.robot.heading, obj.robot.x, obj.robot.y); %Animate %"UNCOMMENT ME" set(l.pth, 'xdata', DATA.path(1,1:DATA.i), 'ydata', DATA.path(2,1:DATA.i)); set(l.lm,'XData',obj.landmarks.apparentPositions(:,1),'YData',obj.landmarks.apparentPositions(:,2)); rectangle('Position',[-2,-2,4,4]); drawnow 这是地标的classdef

classdef landmarks