How do I end this Matlab App Designer switch callback?

I have a switch that I want to let the piston fire to change between 0 and 1 while its on and then end the loop when its off. No matter what I am unable to break the loop.

function FireSwitchValueChanged(app, event)

value = app.FireSwitch.Value;

while strcmp(value,"On")

app.piston_state = 1;

disp(app.piston_state)

pause(0.05)

app.piston_state = 0;

disp(app.piston_state)

drawnow %didnt change anything

if strcmp(value,"Off")

app.piston_state = 0;

disp(app.piston_state)

break

end

end

Answer 1

[Kojiro Saito]

Updated answer

I understand what you're looking for. You can implement flashing lights using timer class.

First, you need to create a private property.

and name the timer property, say timerObj.

    properties (Access = private)
        timerObj % Description
    end

Then, you need to create a private function.

and name the function like myTimerFcn and define it as the following.

    methods (Access = private)    
        function myTimerFcn(app)
            if app.piston_state == 0
                app.piston_state = 1;                
            else
                app.piston_state = 0;
            end
            disp(app.piston_state)
        end
    end

Next, add startupFcn from Callbacks tab.

and define it as follows. It creates a timer class.

function startupFcn(app)
    app.timerObj = timer;
    app.timerObj.TimerFcn = @(~, ~)myTimerFcn(app);
    app.timerObj.Period = 0.1;
    app.timerObj.ExecutionMode = 'fixedSpacing';
end   

Finally, you can call this timer from swithc value changed function.

function FireSwitchValueChanged(app, event)
    value = app.FireSwitch.Value;
    if strcmp(value,"On")        
        start(app.timerObj)
    else
        stop(app.timerObj)
    end
end

I hope this work!

--

Original answer

Switch value changed functions are called once when the switch is pushed, so I don't think while loop is necessary in your FireSwitchValueChanged.

function FireSwitchValueChanged(app, event)
    value = app.FireSwitch.Value;
    if strcmp(value,"On") % or, if value == "On" is also OK.
         app.piston_state = 1;
         disp(app.piston_state)
    else
        app.piston_state = 0;
        disp(app.piston_state)
    end
end

Does this meet your requirement?

[Stylianos Vamvakas]

I need to make the values alternate between 0 and 1 while the switch is on and stop when its off.

An ideal way I would like to do this is by calling the push buttons to alternate infinitely in the switch while its on and stop when its off.

My two push buttons:

            function FireONButtonPushed(app, event)
                app.piston_state = 1;
                disp(app.piston_state)
            end
            % pausibly with a pause(0.1)in between
            function FireOFFButtonPushed(app, event)
                app.piston_state = 0;
                disp(app.piston_state)
            end

So my App works if I click ON OFF ON OFF ON OFF many times manually and I want to automate this process (alternate between my two push buttons infinitely until I turn off the switch.)

I am new to App Designer and you would reallly help me out with some tips.

Thanks!

[Kojiro Saito]

Thank you for your comment. I've updated my previous answer.

[Stylianos Vamvakas]

Thank you very much! This works perfect

[Kojiro Saito]

Great to hear that! Please accept my answer if you can.