matlab - Is it possible to prevent an uitable popup menu from popping up? Or: How to get a callback by clicking a cell, returning the row & column index?

Question

For an user interface I'm programming an uitable. The user chooses an option A,B or C in the first column and the suboption in the second column depends on what was chosen in the first, either A.1,A.2 or A.3 or B.1,B.2 or B.3 or the same for C

The code for the table can be found in Appendix A.

When the user first defines the main option, then automatically the suboptions are reduced accordingly to only valid choices. This is realized by evalulating the CellEditCallback for column 1 and resetting the ColumnFormat for column 2. (function modifySelection in Appendix B) If the user now realizes he made a mistake and needs to edit a suboption another time, then the ColumnFormat is still set according to the previous edited main option and the valid choices are not available unless he re-chooes the main option another time. (see the blue highlighting in picture).

To resolve this, I also implemented the CellSelectionCallback calling the function justifySelection (in Appendix B), which is checking by selection, which option was chosen in column 1 to offer again the right suboptions for column 2. But as this callback reacts on selection, I need to select twice, one time to trigger the CellSelectionCallback and another to actually get my choices. For large tables, this can be very annoying!

So my question is:

Is there a way to prevent the popup menu in column 2 from popping up, until it found out what's the content of the according column 1, so it immediately offers the valid choices?

Or:

How could I detect a mouse click on a cell and get the row and column-index? But without invoking the following selection and popping up action?

I was already raking all available properties but didn't found anything which could be useful. Maybe one could do something using the ButtonDownFcn, but how to get the cell indices? What about the BusyAction property, how can that be used for my purpose?

Any ideas?

I'm sorry in advance to bomb you with so much code, it's already the most minimal example, but fully executable, so you can try it out.

---

Appendix A/B

function fancyUitable 

selector_1 = { 'A'; 'B' ; 'C' };
selector_2 = { 'first select first row!' };

h = figure('Position',[200 100 268 120],'numbertitle','off','MenuBar','none');

defaultData =  repmat( {'select main option...', 'select suboption...'} ,5,1);
columnname =   {'Option                             ',...
                'Suboption                          '};
columnformat = { {selector_1{:}}, selector_2 };
columneditable =  [true true]; 
t = uitable(h,'Units','normalized','Position',[0 0 1 1],...
              'Data', defaultData,... 
              'ColumnName', columnname,...
              'ColumnEditable', columneditable,...
              'ColumnFormat', columnformat,...  
              'RowName',[],...
              'CellEditCallback',@modifySelection,...
              'CellSelectionCallback',@justifySelection);

set(h,'Tag','Config_figure')
set(t,'Tag','Config_table')
end

%   **Appendix B**
%   (part of the same function file)


function modifySelection(~,evt_edit)
if evt_edit.Indices(2) == 1
    modifyPopup( evt_edit.Indices(1) );
end
end

function justifySelection(~,evt_select)
try  %to surpress an unimportant error
    if evt_select.Indices(2) == 2
        modifyPopup( evt_select.Indices(1) );
    end
end
end

---

and finally the single function modifyPopup which rewrites the Columnformat:

function  modifyPopup( row )
    id_group_1 = {'A.1';'A.2';'A.3'};
    id_group_2 = {'B.1';'B.2';'B.3'};
    id_group_3 = {'C.1';'C.2';'C.3'};
    id_default = {'select main option first'};

    myfigure = findobj('Tag','Config_figure');
    config_data = get(findobj(myfigure,'Tag','Config_table'),'Data');
    selector = config_data(row,1);
    selector = selector{1};

    config_format = get(findobj(myfigure,'Tag','Config_table'),'ColumnFormat');
    switch selector
        case 'A'
            config_format{2} = id_group_1';
        case 'B'
            config_format{2} = id_group_2';
        case 'C'
            config_format{2} = id_group_3';
        otherwise
            config_format{2} = id_default;
    end
    set(findobj(myfigure,'Tag','Config_table'),'ColumnFormat',config_format)
end

Bounty: Why just +50? - I guess it's either not possible or the answer is easy, once one had the right initial idea. I'm not looking a for a complex workaround using java object properties etc. Thank you in advance!

---

I include the discussion from the comments here to keep the overview:

If you want to try it out, you can copy the code and follow these steps to reproduce the undesired behaviour:

1. select main option A in the first row.
2. the suboption in the first row then contains the choices A.1, A.2 and A.3.
3. select main option B in the second row, therefore the choices for the suboption in the second row are B.1, B.2 and B.3
4. BUT NOW you want to change the suboption in the first row (directly); you would expect to get the choices A.1, A.2 and A.3; but you don't. You get offered B.1, B.2 & B.3; - Because the last main option you selected was B (though in a diffrent row).

It seems that instead of looking for the last option, you should look at the relevant option. So either make sure that clicking on a suboption does a 'lookup' to see which main option there is,

Thats exactly what I'm looking for! But how could I do that? How to detect the click, get the column&row indices, set the right ColumnFormat and then finally let the cell pop up. The only possibility I see until now is the CellSelectionCallback, but it is executed after the cell already popped up with the invalid choices. I'd need a kind of ClickedCallback, like there is for pushbuttons

or make sure that selecting a main option only sets the suboptions for that row.

That's not possible, you can't set a suboption for a certain row as you need to modify ColumnFormat, which affects the whole table and not just one row.

Answer 1

I would not use a uitable; it's just not suited for this sort of thing.

Here's how I would do it:

function GUIdemo

    %%// Construct GUI

    %// Main figure
    mainFig = figure;
    set(mainFig, 'Color', get(0, 'DefaultUicontrolBackgroundColor'));

    %// Create as many blocks as needed. The only thing you have to do is
    %// figure out the "right" positions for each block
    popupHandles = create_ui_blocks([
        0.00  0.50 1.00  0.35
        0.00  0.15 1.00  0.35]);

    %// This OK button gathers all selected options, and just prints them.
    uicontrol(...
        'style'   , 'pushbutton',...
        'units'   , 'normalized',...
        'parent'  , mainFig,...
        'position', [0.4 0.01 0.2 0.1],...
        'callback', @(~,~)getData(popupHandles),...
        'string'  , 'OK'...
        );


    %%// Helper functions

    %// Create control blocks. Each block is composed of:
    %// - a uipanel as container
    %// - three radio buttons for the main selection
    %// - a corresponding popup or the secondary selection
    function popupHandles = create_ui_blocks(positions)

        %// initialize
        numBlocks = size(positions,1);

        panels = zeros(numBlocks,1);
        groups = zeros(numBlocks,1);
        radios = zeros(numBlocks,3);
        popups = zeros(numBlocks,1);

        %// Build each block
        for ii = 1:numBlocks

            %// The container
            panels(ii) = uipanel(...
                'parent'  , mainFig,...
                'position', positions(ii,:)...
                );

            %// The radio buttons
            groups(ii) = uibuttongroup(...
                'parent'  , panels(ii),...
                'position', [0.05 0.05 0.45 0.9]...
                );
            radios(ii,1) = uicontrol(...
                'style'   , 'radio',...
                'units'   , 'normalized',...
                'string'  , 'A',...
                'parent'  , groups(ii),...
                'position', [0.05 0.66 0.9 0.25]...
                );
            radios(ii,2) = uicontrol(...
                'style'   , 'radio',...
                'units'   , 'normalized',...
                'string'  , 'B',...
                'parent'  , groups(ii),...
                'position', [0.05 0.33 0.9 0.25]...
                );
            radios(ii,3) = uicontrol(...
                'style'   , 'radio',...
                'units'   , 'normalized',...
                'string'  , 'C',...
                'parent'  , groups(ii),...
                'position', [0.05 0.0 0.9 0.25]...
                );

            %// Initially, nothing's selected
            set(groups(ii), 'SelectedObject',[]);

            %// The popups
            popups(ii) = uicontrol(...
                'style'   , 'popup',...
                'units'   , 'normalized',...
                'parent'  , panels(ii),...
                'position', [0.55 0.4 0.4 0.2],...
                'string'  , 'Select main option',...
                'enable'  , 'off'...
                );

            %// On changing radiobutton, correct the string list of the popups
            set(groups(ii),'SelectionChangeFcn', @(~,~)selectionChangeCallback(ii));

            %// This is needed by the OK button callback
            popupHandles = popups;

        end

        %// What happens when clicking a radio button?
        %// NOTE: this is a doubly-nested function
        function selectionChangeCallback(num)
            switch get(groups(num), 'SelectedObject')
                case radios(num,1)
                    set(popups(num), 'string', {'A.1', 'A.2', 'A.3'}, 'enable', 'on');
                case radios(num,2)
                    set(popups(num), 'string', {'B.1', 'B.2', 'B.3'}, 'enable', 'on');
                case radios(num,3)
                    set(popups(num), 'string', {'C.1', 'C.2', 'C.3'}, 'enable', 'on');
                otherwise
                    %// ...
            end
        end

    end

    %// What happens when pressing the OK button?
    function data = getData(popupHandles)
        data = char(cellfun(@(x,y)x{y}, ...
            get(popupHandles, 'String'),...
            get(popupHandles, 'Value'),...
            'UniformOutput', false))         %#ok<NOPRT> //
    end

end

Output in the MATLAB command window when pressing "OK":

data =
    A.1
    B.1

The layout is of course still crude, but you get the idea. Of course, the radio buttons can also be replaced by a popup (more compact), three pushbuttons, or whatever else you like.

The contents of the popups are not related to each other, which is exactly the problem with the uitable approach. In this GUI, changes in the popup's contents can be instantaneous when changing a radio button, simply because you have better control over how to deal with changes.

A programming note: I personally don't like it when handles of individual components in what I treat as a "block" are floating around in the top-level function, which is why I use doubly-nested functions -- it's kind of like encapsulation. Now, when used outside of classes, this is not everyone's cup of tea, so you might want to convert them. Of course, all nested functions are trivially converted to subfunctions; you just have to manually pass a lot more information around.

With this approach, you lose some functionality (the ability to re-size your UI elements), but you gain intuitive behavior of the GUI controls. When these are the choices, I've been trained to develop towards the latter option. The nice bells and whistles will only impress the end-user the first few times round, but the program's basic functionality will become more and more important with increased usage. As you noted yourself, this buggy behavior gets annoying when you have to use the tool a lot; I'd say, drop the resizability in favor of improved control behavior.