Question

我试图在Matlab中运行GUIDE应用程序，但是我遇到了一个问题：当我尝试访问ui表中所选单元格的位置时，持有它的变量（eventdata.Indices）会快速更改回到一个空的向量。这是我的CellSelectionCallback函数：

function varargout = ChannelMatrix(varargin)
% CHANNELMATRIX MATLAB code for ChannelMatrix.fig
%      CHANNELMATRIX, by itself, creates a new CHANNELMATRIX or raises the existing
%      singleton*.
%
%      H = CHANNELMATRIX returns the handle to a new CHANNELMATRIX or the handle to
%      the existing singleton*.
%
%      CHANNELMATRIX('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in CHANNELMATRIX.M with the given input arguments.
%
%      CHANNELMATRIX('Property','Value',...) creates a new CHANNELMATRIX or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before ChannelMatrix_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to ChannelMatrix_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDEs Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help ChannelMatrix

% Last Modified by GUIDE v2.5 14-Oct-2015 17:06:14

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @ChannelMatrix_OpeningFcn, ...
                   'gui_OutputFcn',  @ChannelMatrix_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end

if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT


% --- Executes just before ChannelMatrix is made visible.
function ChannelMatrix_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to ChannelMatrix (see VARARGIN)
clc
% Choose default command line output for ChannelMatrix
handles.output = hObject;
%CONNECT TO SWITCHER
matrixes=cell(12,6,26);
setappdata(0,'matrixes',matrixes);
set(handles.listbox1,'Value',1);
setappdata(0,'index_selected',1); %force Alpha for deafult selection
% Update handles structure
guidata(hObject, handles);

% UIWAIT makes ChannelMatrix wait for user response (see UIRESUME)
% uiwait(handles.figure1);


% --- Outputs from this function are returned to the command line.
function varargout = ChannelMatrix_OutputFcn(hObject, eventdata, handles) 
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure
varargout{1} = handles.output;



% --- Executes when selected cell(s) is changed in uitable1.
function uitable1_CellSelectionCallback(hObject, eventdata, handles)
% hObject    handle to uitable1 (see GCBO)
% eventdata  structure with the following fields (see UITABLE)
%   Indices: row and column indices of the cell(s) currently selecteds
% handles    structure with handles and user data (see GUIDATA)
% --- Executes when selected cell(s) is changed in uitable1.
try 
    currow = eventdata.Indices(1);
    curcol = eventdata.Indices(2);
    adata=get(handles.uitable1,'Data');
    if adata{currow,curcol} == 'V'
      adata{currow,curcol} = '';
    else 
       adata{currow,curcol} = 'V';
    end

    set(hObject,'Data',adata);
end

% --- Executes on button press in cls_ch.
function cls_ch_Callback(hObject, eventdata, handles)
% hObject    handle to cls_ch (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
index_selected = getappdata(0,'index_selected');  %get the number of selected item in listbox
matrixes = getappdata(0,'matrixes'); %get current selection of measurments
table = get(handles.uitable1,'data'); %get the selected channels for this measure
for i=3:14
    for j=1:6
        if table{i-2,j}=='V'
            matrixes{i-2,j,index_selected}='V'; %preform scan and check - add to matrixes selcted values
        end
    end
end
%save changes
set(handles.uitable3,'Data',matrixes(:,:,index_selected)); 
setappdata(0,'matrixes',matrixes);
guidata(hObject, handles);


% --- Executes on button press in opn_ch.
function opn_ch_Callback(hObject, eventdata, handles)
% hObject    handle to opn_ch (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
index_selected = getappdata(0,'index_selected');  %get the number of selected item in listbox
matrixes = getappdata(0,'matrixes'); %get current selection of measurments
table = get(handles.uitable1,'data'); %get the selected channels for this measure
for i=3:14
    for j=1:6
        if table{i-2,j}=='V'
            matrixes{i-2,j,index_selected}=''; %preform scan and check - add to matrixes selcted values
        end
    end
end
%save changes
set(handles.uitable3,'Data',matrixes(:,:,index_selected)); 
setappdata(0,'matrixes',matrixes);
guidata(hObject, handles);

% --- Executes on button press in opn_all.
function opn_all_Callback(hObject, eventdata, handles)
% hObject    handle to opn_all (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
matrixes=cell(12,6,26);
setappdata(0,'matrixes',matrixes); %sets up a new matrix 
set(handles.uitable1,'Data',cell(12,6)); 
set(handles.uitable3,'Data',cell(12,6)); 
set(handles.listbox1,'Value',1);
guidata(hObject, handles);


% --- Executes on button press in clr_selection_btn.
function clr_selection_btn_Callback(hObject, eventdata, handles)
% hObject    handle to clr_selection_btn (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
set(handles.uitable1,'Data',cell(12,6));

% --- Executes on selection change in listbox1.
function listbox1_Callback(hObject, eventdata, handles)
% hObject    handle to listbox1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: contents = cellstr(get(hObject,'String')) returns listbox1 contents as cell array
%        contents{get(hObject,'Value')} returns selected item from listbox1
matrixes=getappdata(0,'matrixes');
index_selected=get(hObject,'Value');
setappdata(0,'index_selected',index_selected);
set(handles.uitable3,'Data',matrixes(:,:,index_selected)); 
set(handles.uitable1,'Data',cell(12,6)); 
guidata(hObject, handles);


% --- Executes during object creation, after setting all properties.
function listbox1_CreateFcn(hObject, eventdata, handles)
% hObject    handle to listbox1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: listbox controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end

这里有什么问题？谢谢！

Answer 1

我认为uitable1_CellSelectionCallback函数的定义没有任何问题。

我构建了一个简单的GUI，它只包含一个uitable，并在调试模式下逐步执行回调，这就是实际发生的事情：

当您在单元格表格上left-click时，uitable1_CellSelectionCallback被正确调用
一切都直到set(hObject,'Data',adata);指令，eventdata.Indices数组包含所选单元格的行和列索引（参见下图中的Function Call Stack）

执行set(hObject,'Data',adata);函数时，MatLab会自动对uitable1_CellSelectionCallback进行新的调用（可能会以某种方式由set触发。在下一张图片中，您可以看到第二个（递归）调用uitable1_CellSelectionCallback中的Function Call Stack和编辑窗口中的白色和绿色箭头调试模式

由于第二次调用不是由实际用户选择的单元格生成的，因此eventdata.Indices为空，因此执行currow = eventdata.Indices(1);时会生成错误

所以，这就是为什么当你点击一个单元格时，它的内容被正确设置为“V”或者你所用的空字符串，但同时（实际上，在MatLab需要进行第二次调用之后）到uitable1_CellSelectionCallback）GUI崩溃。

我不知道这是否会被视为MatLab的bug，但我没有找到任何方法阻止第二次调用uitable1_CellSelectionCallback。

一个可能的解决方案，不是你的（使用try-catch），可以在if块中插入当前的回调代码，检查是否isempty(eventdata.Indices)（即替换{{1}与try）。

这将防止第二次调用“有效”并产生错误，使用if无法避免（即使不阻止第二次调用发生）。

希望这有帮助。

utable的matlab eventdata返回空

1 个答案: