如何从回调函数中输入先前的值?
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05-10-2019 - |
题
我知道这可能是一个简单的问题,但我是Matlab Gui的新手,基本上想获取过去存储在文本框中以替换刚刚输入的值的旧值。例如
- 文本框包含一个有效的字符串,
- 用户进入无效字符串,
- 回调功能,验证输入并意识到新输入是错误,并恢复为旧的上一个值。
应该如何实施或完成? ATM我只是使用GET和设置属性值。以下是一些示例代码:
function sampledist_Callback(hObject, eventdata, handles)
% hObject handle to sampledist (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Hints: get(hObject,'String') returns contents of sampledist as text
% str2double(get(hObject,'String')) returns contents of sampledist as a double
input = str2double(get(hObject,'String'));
if(input < 0 || input > 500)
errordlg('Sampled Dist. must be > 0 and < 500','Sample Dist - Input Error');
set(handles.sampledist,'String',['10']); %<--- I would like this value 10 to be the previous entry!
guidata(hObject,handles);
else
set(handles.sampledist,'String',['',input]);
guidata(hObject,handles);
end
解决方案
只需添加一个新字段 sampledistPrev
到您的手柄结构。
在里面 openingFcn
GUI,用这样的行定义属性:
handles.sampledistPrev = 10; %# or whatever you choose as default value
%# if you want, you can set the default value to the GUI, so that you only need
%# to change it at one point, if necessary, like so:
set(handles.sampledist,'String',num2str(handles.sampledistPrev));
%# don't forget to save the handles structure at the end of the openingFcn
guidata(hObject,handles)
然后,您会这样更新回调:
function sampledist_Callback(hObject, eventdata, handles)
% hObject handle to sampledist (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Hints: get(hObject,'String') returns contents of sampledist as text
% str2double(get(hObject,'String')) returns contents of sampledist as a double
input = str2double(get(hObject,'String'));
if(input < 0 || input > 500)
errordlg('Sampled Dist. must be > 0 and < 500','Sample Dist - Input Error');
set(handles.sampledist,'String',num2str(handles.sampledistPrev)); %reset value be the previous entry!
guidata(hObject,handles); %# Note that you don't need to save the handles structure unless
%# you have changed a user-defined value like sampledistPrev
%# It may still be useful to do it so you always remember
else
set(handles.sampledist,'String',['',input]);
%# also update the reset value
handles.sampledistPrev = input;
guidata(hObject,handles);
end
其他提示
为什么不将“先前的值”存储为该对象的'userData',如下所示:
function sampledist_Callback(hObject, eventdata, handles)
input = str2double(get(hObject,'String'));
if (input < 0 || input > 500)
errordlg('Sampled Dist. must be > 0 and < 500','Sample Dist - Input Error');
val=get(hObject,'UserData');
if isempty(val)
val='';
end
set(hObject,'String',val); %<--- This is where you'd like to set the previous entry value!
guidata(hObject,handles);
else
input=num2str(input);
set(handles.sampledist,'String',input,'UserData',input);
guidata(hObject,handles);
end
end
%yt
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