error message in app designer when closing app

Hello,

I have made an App that works ok hwoever when I close my app (made in app designer), I get the following error message in the Matlab Command screen:

Invalid or deleted object.

Error in Trade_App_1/startupFcn (line 27)

app.Label_1.Text = Label_L;

Error using matlab.apps.internal.GraphicsCallbackProxy/runCallbackFunction (line 23)

Error while evaluating GraphicsCallbackProxy CallbackFcn.

Can any one help? Thx in advance

Thx

Leon

[Jan]

Why does the startup function run during closing the dialog?

[Geoff Hayes]

@Leon - at what point (or under what circumstances) does this line

app.Label_1.Text = Label_L;

execute? Do you (for example) have a timer that updates this text every x seconds? Please clarify.

[Leon]

Hello Geoff

I have an infinity loop in which I update the label with the data from another function

while 1

xxxxxxx

end

And as I mentioned it only happens when I close the app.

BR

Leon

[Leon]

Sorry the answer is of course for both Jan and Geoff

Answer 1

[Geoff Hayes]

@Leon - rather than using a while loop to update your label (which I suspect is the cause of the error), I recommend using a timer instead to do the work that is in the body of the while loop. You would then start the timer and then later stop the timer as the app exits. This should prevent the error from occurring.

[Leon]

Thx for your answer Geoff,

One question. If I use a timer, it could be that while the program is calculating (which might take some time talking about max minutes) the timer will keep updating the data (and also the label as the lable shows the data) and the data is also used for the calculation. So it could be the timer is all the time updating the data and the calculation never gets finished?

Can I pause the timer, or something like that?

BR

Leon

[Geoff Hayes]

@Leon - I guess it all depends upon what your current while loop is doing. Is it calculating some result and then updating the label on the UI? Can one iteration of the timer take minutes to calculate? You can stopt the timer and restart it but there doesn't seem to be any pause or resume capability. Can you provide more details about what happens in the body of your while loop?

[Leon]

Thx for you answer Geoff, I will first work with to see if I can solve it. If not I will come back to you.

BR

Leon