[Scilab-users] uicontrol & wiki

[Samuel Gougeon]

Le 20/12/2016 21:45, paul.carrico at free.fr a écrit :
> Hi
>
> I've been looking to the wiki and an interesting article speaking 
> about GUI developments 
> (https://fr.wikibooks.org/wiki/Découvrir_Scilab/Créer_une_interface_graphique_GUI 
> <https://fr.wikibooks.org/wiki/D%E9couvrir_Scilab/Cr%E9er_une_interface_graphique_GUI> 
> - in French language).
> I've a naive question on the code hereafter: why is it possible 
> to implement several values? no loop is needed nor any breack 
> condition ... surprising but I do not understand :-) (naive question I 
> confess)

If i understand well your question -- rather the same than Jens's one, 
that likes loops too, mainly "while" ones embeding xclick() :) --, i 
would answer the same that i did to him:
A callback is a local (asynchronous) script that is executed each time 
that the interactive component defining it is activated.
So here, each time you press the x^2 button, each time its callback is 
executed.

In the callback, the instruction

x = evstr(e.string);

is not robust, because at the moment the button is pressed, the variable "e"
may no longer exist. Clearing it or overwriting it with something else 
in the meantime
doesnot affect the graphic component. "e" is just a handle (while 
delete(e) would really
delete the component).
For a robust implementation, gcbo.stringis required instead.

HTH
Samuel

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