App designer - close app - Invalid or deleted object.

Hello,

I would like to ask if anyone would know how to get rid of the error message if the for loop is running and I close the application.

number_of_values = length(simulace.PID_regulator_regulacni_velicina{1}.Values.Data);

hold(app.Graph,'on')

plot(app.Graph,simulace.PID_regulator_regulacni_velicina{1}.Values.Time(1:pocet_hodnot),simulace.PID_regulator_regulacni_velicina{1}.Values.Data(1:pocet_hodnot),'b--', 'LineWidth', 1);

graf_regulovana_velicina = plot(app.Graph,simulace.PID_regulator_regulacni_velicina{2}.Values.Time(1),simulace.PID_regulator_regulacni_velicina{2}.Values.Data(1), 'LineWidth', 2);

hold(app.Graph,'off')

for r = 1:pocet_hodnot

hold(app.Graph,'on')

set(graf_regulovana_velicina,'Ydata',simulace.PID_regulator_regulacni_velicina{2}.Values.Data(1:r),'Xdata',simulace.PID_regulator_regulacni_velicina{2}.Values.Time(1:r));

hold(app.Graph,'off')

hold(app.Animation, 'on')

Y = [11-(y/2)+((simulace.PID_regulator_regulacni_velicina{2}.Values.Data(r))*pomer_vykreslene_vysky_nadrze_k_zadani_vysce_zasobniku), 11-(y/2), 11-(y/2), 11-(y/2)+((simulace.PID_regulator_regulacni_velicina{2}.Values.Data(r))*pomer_vykreslene_vysky_nadrze_k_zadani_vysce_zasobniku)];

set(tank,'Ydata', Y);

pause(time)

fill(app.Animation, t1, t2, [0.85 0.85 0.85], 'LineStyle','none');

fill(app.Animation, t3, t4, [0.85 0.85 0.85], 'LineStyle','none');

pause(0.002)

fill(app.Animation, t1, t2, 'b', 'LineStyle','none');

fill(app.Animation t3, t4, 'b', 'LineStyle','none');

hold(app.Animation, 'off')

end

This is only part of the code, but in this part of the code I get an error if it is running in a loop and I close the application. He's probably trying to approach an object that no longer exists in that for loop, but I'm not sure how to solve this problem. I tried to solve the problem via closeFcn, but in vain.

Error message:

Invalid or deleted object.

Matlab version: 2020a

Thank you for any help

Answer 1

[Hari]

Hi Dominik,

I understand that you are encountering an error message when closing your application while a "for" loop is running. The error likely arises because the loop attempts to access an object that no longer exists after the application is closed.

I assume in the MATLAB App Designer application you are using, you have access to modify the event handlers and loop logic. Here are some troubleshooting steps you can try:

1. Error Handling with Try-Catch: You can wrap the loop with a "try-catch" block to gracefully handle any errors that occur if the application is closed during execution.
2. Check for Valid Object Handles: Before updating graphics objects, ensure that they are valid. This can prevent errors when the application is closed.
3. Use an App Property to Control Loop Execution: Create a property in your app that indicates whether the loop should continue running. Set this property to "false" when the application is closing.
4. Implement the Close Request Function: In the "CloseRequestFcn" of your app, set the property to "false" to stop the loop when the app is closing.
5. Update the Loop Condition: Modify the loop to check the "ContinueLoop" property to ensure it stops when the application is closing.

Refer to the documentation of the "try-catch" statement for more information: https://www.mathworks.com/help/matlab/ref/try.html

Refer to the documentation on custom close request functions: https://www.mathworks.com/help/matlab/ref/matlab.ui.figure-properties.html#d123e321341

Hope this helps!