MATLAB: Menu-Based GUI through multiple functions (Error while evaluating UIControl Callback & Error while evaluating UIControl Callback)

guimenuuicontrol

ORIGINAL POST: I'm trying to create a menu-driven GUI that relies on multiple functions. The first function opens the figure, then you click on menus or buttons to open the next function and load the new material onto the page. When trying to call my infopage function inside my setup function through a callback function, I get this error: "Error while evaluating UIControl Callback". The error occurs whether I run the infopage function from clicking in the menu or from clicking the button on the screen. When the button is clicked, nothing on the figure changes (that is, none of the objects I set up in the infopage function show on the figure window).

Here is my setup function:

function setup
% This function initiates the entire project
% and sets us up on the title page
page = 1;
fh = figure('Visible','off',...
    'Units','Normalized',...
    'Position',[0 0 1 1],...
    'MenuBar','None');
ax = axes('Units','Normalized',...
    'Position',[0 0 1 1]);
flagbg = imread('https://upload.wikimedia.org/wikipedia/en/thumb/a/a4/Flag_of_the_United_States.svg/1280px-Flag_of_the_United_States.svg.png');
titleh = uicontrol('Style','Text',...
    'Units','Normalized',...
    'Position',[.3 .3 .4 .4],...
    'FontName','ColonnaMT',...
    'FontSize',60,...
    'String','The United States of America');
subtitleh = uicontrol('Style','Text',...
    'Units','Normalized',...
    'Position',[.3 .3 .4 .2],...
    'FontName','Garamond',...
    'FontSize',20,...
    'String','An Interactive Learning Tool');
buttonh = uicontrol('Style','pushbutton',...
    'Units','Normalized',...
    'Position',[.4 .4 .2 .05],...
    'FontName','Ariel',...
    'FontSize',20,...
    'String','Click to begin...',...
    'Callback',@infopage);
menulabel1 = uimenu('Label','Menu');
    uimenu(menulabel1,'Label','Main Menu','Callback',@titlepage);
    uimenu(menulabel1,'Label','Info','Callback',@infopage);
    uimenu(menulabel1,'Label','Assess','Callback','disp(''save'')');
    uimenu(menulabel1,'Label','Compare','Callback','disp(''save'')');
    uimenu(menulabel1,'Label','Help','Callback','disp(''save'')');
    uimenu(menulabel1,'Label','Quit','Callback','close all',... 
           'Separator','on');
menulabel2 = uimenu('Label','Info');
    uimenu(menulabel2,'Label','State Geography','Callback','disp(''figure'')');
    uimenu(menulabel2,'Label','Flag Recognition','Callback','disp(''save'')');
menulabel3 = uimenu('Label','Assess');
    uimenu(menulabel3,'Label','State Geography','Callback','disp(''figure'')');
    uimenu(menulabel3,'Label','Flag Recognition','Callback','disp(''save'')');
menulabel4 = uimenu('Label','Compare');
    uimenu(menulabel4,'Label','New Figure','Callback','disp(''figure'')');
    uimenu(menulabel4,'Label','Save','Callback','disp(''save'')');
menulabel5 = uimenu('Label','Help');
    uimenu(menulabel5,'Label','New Figure','Callback','disp(''figure'')');
    uimenu(menulabel5,'Label','Save','Callback','disp(''save'')');
menulabel6 = uimenu('Label','Credits');
    uimenu(menulabel6,'Label','%');
    uimenu(menulabel6,'Label','%');
set(ax,'HandleVisibility','off',...
    'Visible','off');
set(fh,'Visible','on')
      function titlepage(~,~)
          close(fh)
          setup
      end
      function infopage(~,~)
          infopage;
      end
  end

Here is my infopage function:

function infopage
StateStruct = loaderfn;
page = 3;
f = figure('Visible','off',...
    'Units','Normalized',...
    'Position',[0 0 1 1]);
directions = uicontrol('Style','text',...
    'Units','Normalized',...
    'Position',[0.12 .8 .25 .1],...
    'FontSize',33,...
    'FontName','Garamond',...
    'String','What state do you want to learn about?');
stateselectionh = uicontrol('Style','popup',...
    'Units','Normalized',...
    'Position',[0.18 0.65 0.13 0.1],...
    'FontSize',17,...
    'FontName','Garamond',...
    'String',{StateStruct.Name},...
    'Callback',@callbackfn);
set(f,'Visible','on');
%Set up the callback function to display selected state's data
      function callbackfn(source,~)
          val = source.Value;
          % Set up the state name display
          statename = sprintf('%s (%s)',StateStruct(val).Name,StateStruct(val).Abbreviation);
          statenameh = uicontrol('Style','text',...
              'Units','Normalized',...
              'Position',[0.6 0.8 0.3 0.1],...
              'String',statename,...
              'FontSize',30,...
              'FontName','TimesNewRoman');
          % Set up the state info display
          capital = sprintf('Capital: %s',StateStruct(val).Capital);
          largestcity = sprintf('Largest City: %s',StateStruct(val).LargestCity);
          statehood = sprintf('Year of Statehood: %s',num2str(StateStruct(val).Statehood));
          population = sprintf('Population: %s',num2str(StateStruct(val).Population));
          area = sprintf('Area: %s',num2str(StateStruct(val).TotalAreaMiles));
          nickname = sprintf('Nickname: %s',StateStruct(val).Nickname);
          gdp = sprintf('GDP: %s',num2str(StateStruct(val).GDP));
          capitalh = uicontrol('Style','text',...
              'Units','Normalized',...
              'Position',[0.5 0.7 0.5 0.1],...
              'String',capital,...
              'FontSize',20);
          largestcityh = uicontrol('Style','text',...
              'Units','Normalized',...
              'Position',[0.5 0.6 0.5 0.1],...
              'String',largestcity,...
              'FontSize',20);
          statehoodh = uicontrol('Style','text',...
              'Units','Normalized',...
              'Position',[0.5 0.5 0.5 0.1],...
              'String',statehood,...
              'FontSize',20);
          populationh = uicontrol('Style','text',...
              'Units','Normalized',...
              'Position',[0.5 0.4 0.5 0.1],...
              'String',population,...
              'FontSize',20);
          areah = uicontrol('Style','text',...
              'Units','Normalized',...
              'Position',[0.5 0.3 0.5 0.1],...
              'String',area,...
              'FontSize',20);
          nicknameh = uicontrol('Style','text',...
              'Units','Normalized',...
              'Position',[0.5 0.2 0.5 0.1],...
              'String',nickname,...
              'FontSize',20);
          gdph = uicontrol('Style','text',...
              'Units','Normalized',...
              'Position',[0.5 0.1 0.5 0.1],...
              'String',gdp,...
              'FontSize',20);
          % Set up the flag display
          url = StateStruct(val).Flag;
          flag = imread(url);
          axish = axes('Units','Normalized',...
              'Position',[0.05 0.10 0.4 0.5]);
          imagesc(flag)
          set(axish,'Visible','off')
      end
  end

The loaderfn function just opens a .MAT file.

Best Answer

Inside your setup function you define

      function infopage(~,~)
          set(titleh,'Visible','off')
          infopage;
      end

as a nested function. The callback created by your setup function is going to return to this nested function, because nested functions have just about the highest priority. That nested function named infopage calls upon infopage, which is its own name. You have programmed in an infinite loop.

To call the outside infopage, you would need to change to

run('infopage')

which would run it as a script rather than as a function. That works because it happens to have no parameters and returns no result. If you needed to pass in parameters or get results then calling it would be a bit tricky.

The easiest way to avoid this problem is to not shadow the names of function you want to call upon. If you want to do something before calling that function, then name the intercepting routine something else.

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MATLAB: Turning Handles Visibility Off In Nested Function

Hi Zachary - if I understand your problem correctly, once the user is on the info page that is displaying the dropdown list of states with (or without) the state flag and a description, then if the user presses the Info choice (from the Menu list) you are expecting the info callback to fire and set the visibility to off for the flag and description. Is this correct?

If I run your software under that assumption and I put a breakpoint at the info callback, I notice that the callback does fire and it tries to set the Visible property to off for these controls. And like you, I notice that nothing happens and the controls remain visible.

You need to look closely at this callback

    function [pages,handles] = info(~,~)
        if page == 1
            set(titleh,'Visible','off');
            set(subtitleh,'Visible','off');
            set(buttonh,'Visible','off');
            [page,handles] = infopage;
        elseif page == 3
            [page,handles] = infopage;
            set(handles.directions,'Visible','off')
            set(handles.stateselection,'Visible','off')
            set(handles.statename,'Visible','off')
            set(handles.capital,'Visible','off')
            set(handles.largestcity,'Visible','off')
            set(handles.statehood,'Visible','off')
            set(handles.population,'Visible','off')
            set(handles.area,'Visible','off')
            set(handles.nickname,'Visible','off')
            set(handles.gdp,'Visible','off')
            set(handles.flag,'Visible','off')
            set(handles.axis,'Visible','off')
        end
    end

If page is identical to 3 (which is the expected case here) then you call infopage to get the page number (?) and the handles associated with this page. The problem is that the majority of the handles within the handles structure are empty. Which makes sense given your call to infopage

 function [page,handles] = infopage
 page = 3;
 handles = struct('directions',[],'stateselection',[],'statename',[],'capital',[],'largestcity',[],...
    'statehood',[],'population',[],'area',[],'nickname',[],'gdp',[],'axis',[],'flag',[]);

The only valid (non-empty) handles are those to directions and stateselection. So you would think that at least these two would be hidden, right? Except (!) there is a problem - every time you call infopage you are re-creating this handles structure and re-creating the controls which will have different handles than those that are presently shown on your GUI. So you will never be able to hide them because you are adding new controls over top of the existing ones.

You only want to call infopage once to initialize all controls for this page (hiding all) and then saving all of these infoPageHandles within your setup function so that you can reference them later.

For example, in your setup function you would do something like (after creating all controls for the first page)

 % create the infopage
 [infoPageHandles] = infopage;

and then your info callback would look like

     function [pages,handles] = info(~,~)
        if page == 1
            set(titleh,'Visible','off');
            set(subtitleh,'Visible','off');
            set(buttonh,'Visible','off');
            page = 3;
            set(infoPageHandles.directions, 'Visible', 'on');
            set(infoPageHandles.stateselection, 'Visible','on');
        elseif page == 3
            set(infoPageHandles.directions,'Visible','on')
            set(infoPageHandles.stateselection,'Visible','on')
            set(infoPageHandles.statename,'Visible','off')
            set(infoPageHandles.capital,'Visible','off')
            set(infoPageHandles.largestcity,'Visible','off')
            set(infoPageHandles.statehood,'Visible','off')
            set(infoPageHandles.population,'Visible','off')
            set(infoPageHandles.area,'Visible','off')
            set(infoPageHandles.nickname,'Visible','off')
            set(infoPageHandles.gdp,'Visible','off')
            cla(infoPageHandles.axis);
        end
    end

We use cla to clear the axis of the image (flag) that has been drawn to it. (You have to be careful here as each time you load the flag, you are "drawing" one over top of the other. Whenever you draw a new flag, you should delete or clear out the old.)

As for the infopage function, see the attached. Note that you will have to handle the current page number from within your setup function (or perhaps rename this to main).

MATLAB: How to use set to change a property of a uicontrol

Change

addstring = {get(texth, 'String')};

addstring = get(texth, 'String');

Best Answer

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MATLAB: Turning Handles Visibility Off In Nested Function

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