Passing variables between GUI's and invalid object or handle

Hi, I am passing variables to 2 seperate GUI's. The code is as follows

setappdata(0,"txt3",app.txt3);
setappdata(0,"N_students",app.N_students);

calling_MpPC_app = MpPC_table;  % sending txt3 and N_students to MpPC_table app
waitfor(calling_MpPC_app);
       
app.Number_of_projs_floated_coded = getappdata(0,'Number_of_projs_floated_coded'); % getting output from MpPC_table app
app.Max_proj_allocations = getappdata(0,'Max_proj_allocations');
                        
app.original_proj_list = app.txt3;
      
setappdata(0,"Max_proj_checker",[app.Number_of_projs_floated_coded(:,1) app.Max_proj_allocations]);
setappdata(0,"txt3",app.txt3)
                        
callingapp = x_gui;  % Sending Max_proj_checker and txt3 to x_gui app
waitfor(callingapp);

                        
app.Roll_nos_GUI = getappdata(0,'Roll_nos_GUI'); % getting output from x_gui
app.Projnames_GUI = getappdata(0,'Projnames_GUI'); 
                        

But when I get the output from x_gui app (last two lines). I get an error invalid object or handle. I think this is due to overwriting done by the previous setappdata command. And storing them in a root directory is as bad as declaring a global variable.

I am using App Designer to create this. But I didn't find any figure handle to specify in the setappdata command. Like In the documentation it says

f=figure
setappdata(f,"Variable name")

But I don't find any line specifying this. I tried putting x_gui instead, But the same error pops and an extra x_gui app window opens.

Any idea on how to do it.

PS: A workaround can be saving them into base and calling them again

Answer 1

[Rik]

The setappdata function also accepts uifigure handles, so you need to use that as input:

app=struct('self',uifigure);
%%
setappdata(app.self,'data',1)
%%
getappdata(app.self,'data')

[Vasista Adupa]

Since I have multiple figures, Can I use any string other than 'self' ?

Like

app = struct('xxx',uifigure)
setappdata(app.xxx,'data',1)
getappdata(app.xxx,'data')

[Rik]

Of course, but since you are already using AppDesigner, there probably is already a field with the handle to the uifigure, which is why I went for this syntax as an example. As soon as one app has the handle to the other, they can use a shared data structure.

[Vasista Adupa]

But I didn't find any such thing like that. The only thing I find is this

PAllocationUIFigure  matlab.ui.Figure

Can you elaborate more please.

[Rik]

AppDesigner has a class-like design philosophy.

That line looks like there is property in you GUI called PAllocationUIFigure with the data type matlab.ui.Figure, meaning that in a callback app.PAllocationUIFigure will contain the handle to the uifigure that is your GUI.

For general advice and examples for how to create a GUI, have look at this thread. I personally have little to no experience with AppDesigner, but you will find usefull doc links on that page.

[Vasista Adupa]

Thank you. Will do it