Alex – the reason is probably that when updating the String property, the Matlab engine places a call to setFixedCellHeight (or some other method that eventually sets the cell height) on the Event Dispatch (EDT queue), and this gets executed in a separate thread asynchronously, a few millisecs later. So if you directly call setFixedCellHeight after setting String, your call is being overridden by the EDT call a few millisecs later and only then the listbox gets repainted, so in the end you see no visible change.
When you add a pause(0.01) before setFixedCellHeight, the EDT call gets executed before your direct call, and so this does produce the requested effect, but due to the intervening listbox repaint you will necessarily see a flicker.

Hi Yair,
Thanks for your response. Annoyingly, and somewhat interestingly, a String update immediately followed by a setFixedCellHeight means that the listbox does NOT update its height at all, if you call getFixedCellHeight the value is still the default MATLAB value. I am not sure why this is.
One way to I found reduce to the flicker is adding a pause(0.01) before setFixedCellHeight call, which does allow the cell height to be set, but it isn’t much of a solution.

There is no simple solution. I think that if you call setFixedCellHeight immediately after updating the String property, without an intervening drawnow or repaint, then there should be no flicker. The flicker indicates that one or both of drawnow or repaint are being called between these two actions.

Hi Yair,
I am having a similar issue to Sebastian, where cell height is reset when listbox.String is updated. I believe MATLAB redraws the listbox whenever the String field is updated, as it doesn’t provide a ‘addElement’ method. I can manually use ‘setFixedCellHeight’ in callbacks following an update of the elements of the listbox, but the resize down to default and the resize back to the fixed height is clearly visible as a flicker, I am wondering if you have any suggestions in fixing this problem?

I tried using the addElement method of the DefaultListModel used in the listbox, but the ListModel is tied to updates in listbox.String field, rather than the other way around.

Many thanks,
Alex

Hi Yair,
I am having a similar issue with Sebastian, for my GUI, I need to add/remove elements to the listbox interactively, causing the cell height to be reverted. I believe this is because MATLAB doesn’t have an addElement method for UIControls, meaning that the listbox needs to be redrawn everytime listbox.String is updated, resetting to the default MATLAB values for cell height and width. I can call ‘setFixedCellHeight’ for every callback that changes the listbox, but this causes flickering and you can see the cells change size everytime it is updated, do you have any suggestions for avoiding this issue?

Thanks

Oh all right. I thought I did something wrong and the settings should be consistent after repaints.

Also the FontMetrics class works like a charm. Thanks a lot for your quick help!

The component is reset/repainted by Matlab when it determines that a component resize is required. You can trap this in the containing panel’s SizeChangedFcn or possibly the Java component’s ComponentResizedCallback callbacks, where you can reapply all the customizations.

Regarding the font size, you can use the Java FontMetrics class to get the necessary information (details)

And something else: On a colleagues PC the HTML text is cut-off at the bottom. Now I found out that he is using a larger Windows font size. Do you have an idea how to detect the needed list item height depending on the used default font?

Best regards,
Sebastian

Of course you can do all that in Java (I don’t know why you call it javax), it’s called a JPopupMenu. But this is a Matlab blog, not a Java blog. So if you insist in using Java for this then I suggest that you check one of the numerous Java resources, either online or offline (books). You can start here.

Hi Yair,
I’m already using javax to customize the ListBox and other uicontrol …..is there any way to add popup menu and submenu with javax ? same for change listbox row color.

rgds,
Michael