Appdesigner, knob value

Hello,

I have an oscilloscope-App in which I want to use 2 knobs , if I switch the knob a value to a variable should be assigned. And this value should be used in a function if a button is then pressed.

That works with one knob but not with the other. I have absolutely no idea why that is.

Does anyone have a clue?

from the appdesigner code:

function EdgeKnobValueChanged(app, event)
value = app.EdgeKnob.Value;

if strcmp(value,'rising')
    app.Edge=2;
    
end
if strcmp(value,'falling')
    app.Edge=1;
end
end
% Value changed function: CouplingKnob
function CouplingKnobValueChanged(app, event)
value = app.CouplingKnob.Value;

if strcmp(value,'AC')
    app.AC=1;
    app.DC=0;
end

if strcmp(value,'DC')
    app.DC=1;
    app.AC=0;
end            
end

function StartButtonPushed(app, event)

if strcmp(app.Trigger,'Simple edge')
    somefunction(app.Edge);  %the value for app.Edge cant be used in the function 
end
end

I would be really grateful for any kind of help.

Answer 1

[Voss]

uiknob 'Value' is a numeric (https://www.mathworks.com/help/matlab/ref/matlab.ui.control.knob-properties.html), so both strcmp calls return false, so app.Edge is not set.

value = 3; % some numeric value

strcmp(value,'rising')

ans = logical
   0

strcmp(value,'falling')

ans = logical
   0

Regardless of that, you should initialize app.Edge, app.AC, and app.DC in your startupFcn to be the values corresponding to their repective knobs, in case the user clicks the start button without interacting with the knobs.