How to choose data in nested struct array using popup menu while the number of field is different in each floor of the nested struct array ?

Hello,

I have data organize in a nested struct array i.e : on the first floor of this struct I have different groups of data that are also themself struct array.

I wonder if it's possible to build a GUI that will allow the user to specify the data to be display but I may not necessarily have the same number of fields in each floor of my nested struct array so when choosing a field in the second floor I should keep in memory which field was selected on the first floor. To be more specific consider an example with three floor where on the first floor I have 2 struct array one whith 1 struct array with 2 fields to be display and a second with 2 struct array with respectively 3 and 4 fields to be display. So I wonder if it's possible to build a GUI with popup menu to allow the user to choose which filed to display ?

So far I have a small GUI with 3 popup menu and a draw button (plus some other draw option not important here) but when I change the selected value of the second popup menu I need to refere to the selected value of the first one in order to update the number of fields for the third popup menu. Here is the code I got :

cellgroup = cell(numel(fieldnames(data)),1); % first floor struct are call 'group'
for g=1:numel(fieldnames(data))
    cellgroup{g} = ['Group ',num2str(g)];
end
Controlfig = figure('Name','Display control panel',...
    'NumberTitle','off',...
    'Units','pixels',...
    'Position',[50 50 450 225]);
% Just some text do invite the user to choose fields
Textinfo = uicontrol('Parent',Controlfig,...
    'Units','pixels',...
    'Style','text',...
    'String','Choose your display options :',...
    'FontName','MS Sans Serif',...
    'FontWeight','bold',...
    'FontSize',12,...
    'Position',[9 202 241 23]);
% Thrid floor fields to be display are called pulses
Pulsepopup = uicontrol('Parent',Controlfig,...
    'Units','pixels',...
    'Style','popupmenu',...
    'String',{'Pulse 1'},...
    'Enable','off',...
    'Position',[9 85 127 27]);
% Second floor fields are called zones
Zonepopup = uicontrol('Parent',Controlfig,...
    'Units','pixels',...
    'Style','popupmenu',...
    'String',{'Zone 1'},...
    'Enable','off',...
    'Position',[9 133 127 27],...
    'Callback',{@chooseZone,Grouppopup,Pulsepopup,data});
% First floor fields are called groups
Grouppopup = uicontrol('Parent',Controlfig,...
    'Units','pixels',...
    'Style','popupmenu',...
    'String',cellgroup,...
    'Position',[9 168 127 27],...
    'Callback',{@chooseGroup,Zonepopup,Pulsepopup,data});
% The push button to draw the data
Drawbutton = uicontrol('Parent',Controlfig,...
    'Units','pixels',...
    'String',{'Draw'},...
    'Position',[145 4 130 22],...
    'Callback',{@Datadraw,Grouppopup,Zonepopup,Pulsepopup,data});

% When the user choose a group update the possible fields to be selected in second and third floor
function chooseGroup(Grouppopup,Eventdata,Zonepopup,Pulsepopup,data)
set(Zonepopup,'Value',1)
set(Pulsepopup,'Value',1)
% One of the field is not a struct array but just some information
cellzone = cell(numel(fieldnames(data.(['Group_',num2str(Grouppopup.Value)])))-1,1);
for z=1:(numel(fieldnames(data.(['Group_',num2str(Grouppopup.Value)])))-1)
    cellzone{z} = ['Zone ',num2str(z)];
end
% 5 fields of information here
cellpulse = cell(numel(fieldnames(data.(['Group_',num2str(Grouppopup.Value)]).(['Zone_',num2str(Zonepopup.Value)])))-5,1);
for p=1:(numel(fieldnames(data.(['Group_',num2str(Grouppopup.Value)]).(['Zone_',num2str(Zonepopup.Value)])))-5)
    cellpulse{p} = ['Pulse ',num2str(p)];
end
% Allow the user to choose second and third floor field
set(Zonepopup,'String',cellzone)
set(Zonepopup,'Enable','on')
set(Pulsepopup,'String',cellpulse)
set(Pulsepopup,'Enable','on')
end

% Update third floor field when the user choose a second floor one
function chooseZone(Zonepopup,Eventdata,Grouppopup,Pulsepopup,data)
set(Pulsepopup,'Value',1)
grp = get(Grouppopup,'Value');
cellpulse = cell(numel(fieldnames(data.(['Group_',num2str(grp)]).(['Zone_',num2str(Zonepopup.Value)])))-5,1);
for p=1:(numel(fieldnames(data.(['Group_',num2str(grp)]).(['Zone_',num2str(Zonepopup.Value)])))-5)
    cellpulse{p} = ['Pulse ',num2str(p)];
end
set(Pulsepopup,'String',cellpulse)
end

function Zonedraw(Drawbutton,Eventdata,Grouppopup,Zonepopup,Pulsepopup,data)
if allowdraw = strcmp(get(Zonepopup,'Enable'),'on');
    % draw the data selected
else
    disp('choose a group first')
end
end

So I understand why this could not work : because I refert to Grouppopup in Zonepopup callback before Groupopup has been define so I get this error when selecting a zone :

Error using matlab.ui.control.UIControl/get
Invalid or deleted object.

Error in LiveEditorEvaluationHelperESectionEval>chooseZone (line 652)
grp = get(Grouppopup,'Value');
 
Error while evaluating UIControl Callback.

But I realy don't know how I could possibly do otherwise, I would be very thankfull if you have any suggestion ?

[Geoffrey Schivre]

I found a way to remedy to my problem by passing the current group selected in second popup tag. But I'm still open to other solution !