How to access handles of another MATLAB GUI

Question

I have two GUIs in MATLAB. I stored some values in GUI1 in the handles structure, so that when it displays in the Command Window, it looks like this:

        GUI1: [1x1 Figure]
        pushbutton2: [1x1 UIControl]
              text2: [1x1 UIControl]
              edit1: [1x1 UIControl]
             output: [1x1 Figure]
              val1: 0

I want to use val1 to set a value, counter, in GUI2. I don't have any command to initialize counter in GUI2. How do I access the handles of GUI1 in GUI2?

I tried to use the command guidata(findobj('Tag', 'GUI1')) to get those handles, but it shows me that it's empty.

I tried doing the following:

In GUI1, under OpeningFcn:

handles.val1 = 0;
guidata(hObject, handles);
setappdata(handles.GUI1,'val1', handles.val1)

And in GUI2, in a pushbutton function:

counter = getappdata(handles.GUI1,'val1')

But that doesn't seem to work either! It gives me an error saying, "Reference to non-existent field 'GUI1'."

I have the handle visibility on for GUI1, and a tag set to "GUI1". Why am I still having this issue?

Maybe try counter=findobj('type','double'), or counter=findobj('type','double','parent',GUI1) — Adiel

scmg scmg · Accepted Answer · 2015-06-01T14:42:20

You should set the GUI's Tag before finding object, i.e GUI1's Tag = GUI1. Then you can try to find all children of root object:

gui1_H = get(0,'Children', 'Tag', 'GUI1');

or just use findobj:

gui1_H = findobj('Type', 'figure', 'Tag', 'GUI1');

In some cases, the GUI's HandleVisibility is set to off, in this case, you can use findall in your GUI2:

gui1_H = findall(0, 'Type', 'figure', 'Tag', 'GUI1');

And get the handle struct:

data = guidata(gui1_H);
disp(data.val);

Note that you are currently opening 2 GUIs at the same time, so if you keep both GUIs' default Tag to be figure1, then gui1_H will not be counted as graphic object's handle, hence you also cannot get its guidata.

How to access handles of another MATLAB GUI

1 Answers