Re: Function handle with arguments for GUI callback

[Arnaud Miege]

On 11 March 2013 17:34, Michael Goffioul <address@hidden> wrote:

Using a cell array is the right approach. It is supported. What error do you get and what code are you using? Also please note that a GUI callback always get the object handle and an event data as first 2 arguments. Whatever arguments you specify in the cell array starts at position 3 in the callback argument list.

Michael.

Thanks, I have made some progress since my initial email.

In my main function, I create a variable called "gui" as the output of a sub-function called create_interface:

gui = create_interface;

In the sub-function create_interface, I add various fields to the gui structure which are handles to the various UI components, such as:

% Add pop-up menus for dimension choice of each input

strings = {'Nominal dimensions|Measurement file'};

width = [0.5 0.5 0.5];

gui.dim_choices = cell(size(gui.inputs_txt));

for k=1:length(gui.inputs_txt)

gui.dim_choices{k} = uicontrol('Style','popupmenu','String',strings,...

        'Units','normalized','Position',[0.23 y_pos(k) width(k) 0.1],...

        'BackgroundColor','w','Parent',gui.inputs_panel,'Callback',...

address@hidden,num2str(k),gui});

end

I have worked out that the first argument to the function handle callback needs to be converted to a string. I am also passing the gui structure as a second argument because I couldn't figure out a way of using the second default argument (eventdata - there doesn't seem to be much documentation about it).

If we then come out of create_interface, I have various functions for the callbacks, all at the same level as create_interface. The one of interest is (I have only put some trivial commands to debug what is going on):

function update_browse_btn(src,data,k,gui)

% Called when user activates popup menu 

disp(['k = ' num2str(k)]);

        val = get(src,'Value')

gui

end

That works well and displays the following in the console when I change the drop-down menu:

>> k = 1

val =  2

gui =

  scalar structure containing the fields:

    Window =  1

    outputs_panel = -28.293

    inputs_panel = -27.709

    graph_panel = -26.338

    HelpMenu = -25.343

    inputs_txt =

    {

      [1,1] = -23.566

      [2,1] = -22.087

      [3,1] = -21.487

    }

    browse_btns =

    {

      [1,1] = -20.863

      [2,1] = -19.427

      [3,1] = -18.260

    }

    dim_choices =

    {

      [1,1] = [](0x0)

      [2,1] = [](0x0)

      [3,1] = [](0x0)

    }

If I then change the callback function slightly to:

function update_browse_btn(src,data,k,gui)

% Called when user activates popup menu 

disp(['k = ' num2str(k)]);

        val = get(src,'Value')

gui.browse_btns

end

I am still getting the expected output:

>> k = 1

val =  2

ans =

{

  [1,1] = -20.090

  [2,1] = -19.064

  [3,1] = -18.774

}

However, if I start using the index k (which has a sensible value between 1 and 3), as in:

function update_browse_btn(src,data,k,gui)

% Called when user activates popup menu 

disp(['k = ' num2str(k)]);

        val = get(src,'Value')

gui.browse_btns(k,1)

end

I get the following error:

>> k = 1

val =  2

error: update_browse_btn: A(I,J): row index out of bounds; value 49 out of bound

 3

error: called from:

error:   <path_to_my_file> at line 185, colu

mn 3

I can't then close the GUI, I need to click on the console to activate it, which triggers the following error message:

error: octave_base_value::convert_to_str_internal (): wrong type argument `<unkn

own type>'

error: octave_base_value::convert_to_str_internal (): wrong type argument `<unkn

own type>'

error: octave_base_value::convert_to_str_internal (): wrong type argument `<unkn

own type>'

error: octave_base_value::double_value (): wrong type argument `<unknown type>'

error: octave_base_value::convert_to_str_internal (): wrong type argument `<unkn

own type>'

error: octave_base_value::convert_to_str_internal (): wrong type argument `<unkn

own type>'

error: octave_base_value::convert_to_str_internal (): wrong type argument `<unkn

own type>'

I then need to press Enter to regain control and close the figure with the close command.

The syntax gui.browse_btns{k} results in a similar behaviour.

Any idea why although k is definitely equal to 1, it says it's 49 when trying to index the structure?

Many thanks,

Arnaud