I am trying to create a simple UDD class similar to this. The class is the same as simple.object with simple.object being a subclass of uipanel. I am trying to include a uicontrol slider on the panel during construction. When I open up Matlab, the first time I run the constructor, I always get the error: The class name ‘ScrollablePanel’ already exists. If I run it again, it works without error. Is there a way I can make it work the first time? If it helps, here is the constructor:

function this = ScrollablePanel(varargin)
   this = uiStrider.ScrollablePanel;
   set(this,varargin{:});
   set(this,'SliderHandle',uicontrol('Parent',handle(this), 'Style','Slider','Units','Pixels'));
end

Thanks for doing this website. I use it all the time,
Matt

Your example using ‘PropertyPostSet’ works. I thought that this would lead to a racing condition, but it doesn’t. I will work from here on …

Thanks

Sebastian

PS to anyone, who wants to try something similar:

1) Define property “PL” (-> PropListener) in schema.m file:

p = schema.prop(MyClass, ‘PropListener’, ‘handle vector’);

2) Specify ‘PropertyPostSet’ listener and nested function to handle the property change in the MyClass.m – file.

function obj = MyClass(varargin)

obj = MyPackage.MyClass;
obj.PL=handle.listener(obj, obj.findprop(‘XLim’), ‘PropertyPostSet’,@MF);

function MF(~, in)
obj.xlim = round(in.NewValue);
end

end

– The handle to the listener is saved in property “PL”, otherwise the function “MF” would not be called. This is similar to what is done in the “linkprop” command (s. Matlab documentation).

– Since “MF” is specified as nested function, obj is still in scope and the new value (in.NewValue) can be checked, altered and passed to the object.

@Sebastian – Normally you can overload a propertyof the superclass in a subclass. I think the problem in this case MATLAB will not allow you to set the type of your overloaded XLim property to axesXLimType and no other type will work. XLim does generate Events so you could try something like:

lis = handle.listener(a, a.findprop('XLim'), 'PropertyPostSet', 'a.XLim = [11,20];')

To solve your problem.

In the upcoming section on UDD events we will show how to placecode like this in a a class.

Best Regards,

Donn

Simple example:
Suppose I create a UDD-subclass of HG-axes named mAxis and want to be able to restrict the user to certain xlims, e.g. only multiples of 10. How can I intercept a call like

>> set(H, 'xlim', [11 20])   % Where H is a mAxis object

On the one hand side, if I make xlim a property of the class (using “schema.prop …” in the schema.m-file) and supply the according SetFunction, I can no longer pass the property to the “superclass”, i.e. the axis object.

On the other hand Matlab will not let me specify a SetFunction in the mAxis.m, because the xlim property is protected.

OK, maybe you can hint me to some solution.

Cheers

Sebastian