How can I close a while loop in a callback function

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jianshen li 2020-8-27

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/585104-how-can-i-close-a-while-loop-in-a-callback-function

评论： jianshen li 2020-8-27

function SwitchValueChanged(app, event)

value = app.Switch.Value;

while(value=='On')

pause(0.05);

end

This is a callback for Switch in APP Designer. When Switch is switched to On, the while loop is executed, and when Switch is switched to Off, the loop is terminated.

In fact, when switching to On, after the loop starts, switching the Switch state again will not enter the callback function, resulting in the failure to terminate the while loop.

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Answer 1

Mehmed Saad 2020-8-27

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https://ww2.mathworks.cn/matlabcentral/answers/585104-how-can-i-close-a-while-loop-in-a-callback-function#answer_485639

在 MATLAB Online 中打开

if value is 'off' the while loop condition will give error because on and off are not of same size

so replace it will strcmp

while(strcmp(value,'On'))

2nd is you are writing callback, and everytime you press switch button, it will call function but with new inputs. In your case, when value is on while loop will run forever so this approach is not right

So donot put while loop in callback, put it in you main code like this

%% Not for callback
value = app.Switch.Value;
while(strcmp(value,'On'))
    pause(0.05); 
   value = app.Switch.Value;  
end

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jianshen li 2020-8-27

Thank you for your detailed answers.

I want my code to run when the switch is on and stop when it is off. You said to put the code in the main code. What part of the main code is in the app designer? I'm a beginner about APP Designer.

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