MATLAB: Implementing listener and callback, infinite loop

listeneroop

Hi,
My problem follows the one I described here:
https://fr.mathworks.com/matlabcentral/answers/362302-how-to-put-condition-based-on-a-property-in-a-property-accessor?s_tid=prof_contriblnk
So in my example, a class "Car" as properties "Brand" and "Color".
Brand can only be 'Ferrari' or 'Mercedes', and 'Color' can only be Yellow or Red for the Ferrari and Black or Silver for the Mercedes.
I did put Color as Dependent and added a set method with a sort of pair property of color.
When set or get is called for Color, its a "twin" property that holds the value.
I have a list of valid Color input for the Ferrari and the Mercedes, so that when setting the Color of the car it as to be right.
It works fine, but if I change the Brand, then the Color is invalid but there is no check for that.
So I would like the Color Prop to change to the first Valid one (in the list) whenever "Brand" is modified.
For that I tried to implement a property that listen to the Brand property. ==>"BrandChangeListener"
I made the Car class to inherit form handle. Then I was getting a warning with my set methods, so I modified them from: obj = set.propName(obj, value) to set.propName(obj, value), so that it does not return the object anymore. That fixed the warning.
In the constructor I tried to implement a listener:
myCar.BrandChangeListener = event.proplistener(myCar, findprop(myCar, 'brand'),'PostSet', @ResetColor);
On this line I get the error: While adding a PostSet listener, property 'brand' in class 'car' is not defined to be SetObservable.

Best Answer

Personally I always use addlistener syntax when adding a listener. I am not familiar with your syntax, but it seems it will still work. The 'See Listen for Changes to Property Values.' link takes you to a page where all the examples use addlistener, but since you are getting this error message I assume the two syntaxes are interchangeable.
Basically you need to just follow what the error tells you and add the 'SetObservable' attribute to your 'brand' property
e.g.
properties( SetObservable, Access = public )
   brand
end
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