Question

matlab 建立 图形演示系统 书上找的，，但是发现不能运行

screen=get(0,'Screensize')
W=screen(3);H=screen(4);
figure('color',[1,1,1],'Position',[0.2*H,0.2*H,0.5*W,0.3*H],'Name','图形显示系统','Numbertitle','off','Menubar','none')
hplot=uimenu(gcf,'Label','&Plot')
uimenu(hplot,'Label','since wave','callback',['t=-pi:pi/20:pi;','y=sin(t)','plot(t,y);','set(hgon,"Enable","on");','set(hgoff,"Enable","on");','set(hgon,"Enable","on");','set(hgon,"Enable","on");']);
%定义plot菜单栏
uimenu(hplot,'Label','cosine wave','callback',['t=-pi:pi/20:pi;','plot(t,cos(t));','set(hgon,"Enable","on");','set(hgoff,"Enable","on");','set(hgon,"Enable","on");','set(hgon,"Enable","on");']);
hoption=uimenu(gcf,'Label','&option')
hgon=uimenu(hoption,'Label','&Grid on','Callback','grid on','Enable','off');
hgoff=uimenu(hoption,'Label','&Grid off','Callback','grid off','Enable','on');
hgon=uimenu(hoption,'Label','&Box on','Callback','grid on','Enable','off');
hgoff=uimenu(hoption,'Label','&Box off','Callback','grid off','Enable','on');
%
hwincor=uimenu(hoption,'Label','&Window color','Separator','on');
%wrong

uimenu=(hwincor,'Label','&Blue','Accelerator','b','Callback','set(gcf,"color","b");');
uimenu=(hwincor,'Label','&Red','Accelerator','r','Callback','set(gcf,"color","r");');
uimenu=(hwincor,'Label','&Yellow','Accelerator','y','Callback','set(gcf,"color","y");');
uimenu=(hwincor,'Label','&White','Accelerator','w','Callback','set(gcf,"color","w");');
uimenu=(gcf,'Lable','&Quit','Callback','close(gcf)')

Answer 1

错误已修正，主要有以下几点：

1）最后四局等号多余

2）单引号里面有单引号应该用两个单引号而不是双引号

3）其他一些逻辑错误，比如grid on和box on都叫hgon会有问题，把box on重命名为hbon

4）错误很多，不是抄错了，就是原书质量很差，不建议阅读。

下面是修改后的代码，效果还不错。

 

screen=get(0,'Screensize');
W=screen(3);H=screen(4);
figure('color',[1,1,1],'Position',[0.2*H,0.2*H,0.5*W,0.3*H],'Name','图形显示系统','Numbertitle','off','Menubar','none')
hplot=uimenu(gcf,'Label','&Plot');
uimenu(hplot,'Label','since wave','callback',['t=-pi:pi/20:pi;','y=sin(t);','plot(t,y);box on;grid off;','set(hgon,''Enable'',''on'');','set(hgoff,''Enable'',''off'');','set(hbon,''Enable'',''off'');','set(hboff,''Enable'',''on'');']);
%定义plot菜单栏
uimenu(hplot,'Label','cosine wave','callback',['t=-pi:pi/20:pi;','plot(t,cos(t));;box on;grid off;','set(hgon,''Enable'',''on'');','set(hgoff,''Enable'',''off'');','set(hbon,''Enable'',''off'');','set(hboff,''Enable'',''on'');']);
hoption=uimenu(gcf,'Label','&option');
hgon=uimenu(hoption,'Label','&Grid on','Callback','grid on;set(hgoff,''Enable'',''on'');set(hgon,''Enable'',''off'');','Enable','off');
hgoff=uimenu(hoption,'Label','&Grid off','Callback','grid off;set(hgon,''Enable'',''on'');set(hgoff,''Enable'',''off'');','Enable','off');
hbon=uimenu(hoption,'Label','&Box on','Callback','box on;set(hboff,''Enable'',''on'');set(hbon,''Enable'',''off'');','Enable','off');
hboff=uimenu(hoption,'Label','&Box off','Callback','box off;set(hbon,''Enable'',''on'');set(hboff,''Enable'',''off'');','Enable','off');
%
hwincor=uimenu(hoption,'Label','&Window color','Separator','on');
%right

uimenu(hwincor,'Label','&Blue','Accelerator','b','Callback','set(gcf,''color'',''b'');');
uimenu(hwincor,'Label','&Red','Accelerator','r','Callback','set(gcf,''color'',''r'');');
uimenu(hwincor,'Label','&Yellow','Accelerator','y','Callback','set(gcf,''color'',''y'');');
uimenu(hwincor,'Label','&White','Accelerator','w','Callback','set(gcf,''color'',''w'');');
uimenu(gcf,'Label','&Quit','Callback','close(gcf)')

Answer 2

书中程序不能运行主要有两个问题：

1. 双引号输入错误，应该是连着输入四个单引号。

2. 代码：

   uimenu(hplot,'Label','since wave','callback',...

   ['t=-pi:pi/20:pi;','y=sin(t)','plot(t,y);','set(hgon,"Enable","on");','set(hgoff,"Enable","on");','set(hbon,"Enable","on");','set(hboff,"Enable","on");']);

   中句柄变量：hgon、hgoff、hbon、hboff未定义。

3. 修改的一种做法（可以运行）：将后面关于hgon、hgoff、hbon、hboff定义的代码提前。

   完整代码如下：

   screen = get(0,'ScreenSize');
   W = screen(3);
   H = screen(4);
   figure('Color',[1,1,1],'Position',[0.2*H,0.2*H,0.5*W,0.3*H],...
   'Name','图形演示系统','NumberTitle','off','MenuBar','none');
   % 定义Plot,Option一级菜单名
   hplot = uimenu(gcf,'Label','&Plot');
   hoption = uimenu(gcf,'Label','&Option');
   % 定义Option菜单项（提前定义变量hgon、hgoff、hbon、hboff）
   hgon = uimenu(hoption,'Label','&Grid On',...
   'Call','grid on','Enable','off');
   hgoff = uimenu(hoption,'Label','&Grid off',...
   'Call','grid off','Enable','off');
   hbon = uimenu(hoption,'Label','&Box On',...
   'Separator','on','Call','box on','Enable','off');
   hboff = uimenu(hoption,'Label','&Box off',...
   'Call','box off','Enable','off');

   % 定义Window Color 菜单项
   hwincor = uimenu(hoption,'Label','Window Color','Separator','on');
   uimenu(hwincor,'Label','&Red','Accelerator','r',...
   'Call','set(gcf,''Color'',''r'');');
   uimenu(hwincor,'Label','&Blue','Accelerator','b',...
   'Call','set(gcf,''Color'',''b'');');
   uimenu(hwincor,'Label','&Yellow',...
   'Call','set(gcf,''Color'',''y'');');
   uimenu(hwincor,'Label','&White',...
   'Call','set(gcf,''Color'',''w'');');
   % 定义Plot菜单项
   uimenu(hplot,'Label','SineWave','Call',...
   ['t = -pi:pi/20:pi;','plot(t,sin(t));',...
   'set(hgon,''Enable'',''on'');',...
   'set(hgoff,''Enable'',''on'');',...
   'set(hbon,''Enable'',''on'');',...
   'set(hboff,''Enable'',''on'');']);
   uimenu(hplot,'Label','Cosine Wave','Call',...
   ['t = -pi:pi/20:pi;','plot(t,cos(t));',...
   'set(hgon,''Enable'',''on'');',...
   'set(hgoff,''Enable'',''on'');',...
   'set(hbon,''Enable'',''on'');',...
   'set(hboff,''Enable'',''on'');']);
   % 定义Quit菜单项
   uimenu(gcf,'Label','&Quit',...
   'Call','close(gcf)');