MATLAB Answers


uitable updates behave strangely

Asked by Ali Komai on 29 Aug 2019
Latest activity Answered by Ali Komai on 3 Sep 2019
I have a very peculiar problem. I programmed a trading application and ran into the following problem.
I have an uifigure and within this uifigure I have a tabgroup with two tabs. In this two tabs I have uitables showing the open positions of my application. One tab for stocks from the UK and one for US stocks.
Every 3 mins or when there was opened or closed a position the tables are updated. The update always affects only two columns per stock if the stock is already in the table. If it is a new position a line to the table is added.
So far so good, now comes the strange part. If I set a breakpoint right before the uitables are created and trace over the two lines both tables are created in their respective tab and all is fine. I can run the program from this point and it updates the tables just as I wish - great.
But if I don't set the breakpoint infront of the table creating lines and let the program simply run, the tables never show up in my tabs and are also not updated. That means not shown. I can go into debug mode and see and the data for both table is there in is also handled correctly, it is just not displayed on the screen.
I tried adding both a small pause after the uitable creation and also tried issueing drawnow but nothing helps. I have to trace over this two lines manually if I want to see my tables.
P.S.: Setting the breakpoint right after the two lines that are supposed to create the tables does not work. I have to execute the two lines manually to see the tables.


I could solve the problem by simply inserting a longer pause (3s did the trick) after the first table-creating line.
I tried this before with a shorter pause which obviously wasn't sufficient.
@Ali Komai: can you upload an MWE that shows this behavior?
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2 Answers

Answer by Ali Komai on 3 Sep 2019
 Accepted Answer

The problem is solved by passing the data to the uitable function in frm of a cell-array instead of a table. Then everything works fine without pauses or anything special.


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Answer by Luna
on 30 Aug 2019

I had that problem before, I simply solved it by changing the focus of the tabs while creating the uitables. Please try following steps I hope it works:
  • Make your first tab active, create the uitable inside of that tab. (Parent of the uitable should be a container in that tab)
  • Make your second tab active, create the uitable inside of that tab, too.
  • If you want to make an update then activate the corresponding tab, make your updates.
You should programatically make the activation by changing the SelectedTab property of your uitabgroup.


Thank you for the advise.
Luckily the problem was solved by a simple pause(3) after the uitable call (like I stated in my comment above). So a little patience was all that was needed. :-)
I do not really know what I'm doing differently, however the problem reoccured and no pause seems to alleviate it.
Therefore I tried now selecting the current tab programmatically like you suggest but this doesn't change anything. But maybe I'm doing it wrong.
If I set a breakpoint after the first uitable call the first table will be displayed. Do I set a breakpoint after the second call to uitable, only the second table is displayed.
Here is my code for creating the tabs and tables:
UIFigure = uifigure('Position',[200 220 1000 500]); % create status window
tg = uitabgroup(UIFigure,'Position',[100 240 800 240]);
tabUK = uitab('Parent',tg,'Title','UK','Scrollable','on');
tabUS = uitab('Parent',tg,'Title','US','Scrollable','on');
tg.SelectedTab = tabUK;
posTableUK = uitable(tabUK,'Data',positionsUK,'Position',[0 240 780 240],'ColumnFormat',{[],[],[],'bank','bank'});
tg.SelectedTab = tabUS;
posTableUS = uitable(tabUS,'Data',positionsUS,'Position',[0 240 780 240],'ColumnFormat',{[],[],[],'bank','bank'});

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