Thanks,
Dhanya

The possible com.mathworks.mwswing.checkboxtree.SelectionState values are: MIXED, NOT_SELECTED and SELECTED, which are pretty-much self-explanatory.

I assume that you are using GUIDE to create your GUI. In such a case, the *_OutputFcn() function is called after the entire GUI is created, immediately before the control is passed to the user. In this function, you have access to all handles. See this doc-page.

I’m having difficulties (probably the same as weilang had) disabling the mixed state of JCheckBox. If it has not been in mixed state, then I can toggle its state and appeareance (selected or deselected) by clicking. But soon as I put it in mixed state, changing the state by clicking does not affect its appeareance.
Also I could not find the method for setting the state of JCheckBox to selected/deselected. For MWCheckbox it is “jCB.setSelected(1)” (or “0”).
To put it in a nutshell:
1. What is the opposite of “jCB.putClientProperty(‘selectionState’, SelectionState.MIXED);”?
2. What is the counterpart of “jCB.setSelected(1)”?

Third problem: I wrote a Callback function to switch on or off all subordinated checkboxes, if my JCheckBox has been clicked: (Still only works when not in mixed mode.)

function Tristatecheckbox_Callback(hObject,eventdata,subCBs) % subCBs as CELL
isSelected=hObject.isSelected;
n=size(subCBs);
for i=1:n(2)
   set(subCBs{i},'Value',isSelected);
end

Now my problem is where/when to associate this function with Java Callbacks.
I wrote this code snippet, which is working:

hjCB = handle(handles.jCB,'CallbackProperties'); % initialised with "handles.jCB = javax.swing.JCheckBox(..."
subCBs={handles.CB1,handles.CB2,handles.CB3};
set(hjCB,'ItemStateChangedCallback',{@Tristatecheckbox_Callback,subCBs});

First I put it right after the JCheckBox’s creation, which is in the CreateFcn of a panel. But in CreateFcns there are no visible handles but those of the object in creation, so handles.CB1 can not be allocated.
For trial&error, I put it in the CallbackFcn of a dummy pushbutton and just clicked this dummy before using the rest, but later I need this snippet to be done before the user can do anything with the GUI.
3. Is there a function running right after the GUI is created, with access to all the handles? Which one? And if no, where else to put the code?

Thanks a lot!