[plt-scheme] Key events within a frame

Jean-Guillaume Pyraksos wrote:

>  For list-related administrative tasks:
>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>
> In order to program a game, i want to listen to keyboard events within 
> a frame. But i must click in the frame to get the focus. I tried some 
> function (whose name i don't remember) to get that focus but it didn't 
> work. How can i avoid the click so that the frame can directly get the 
> keyboard ? Thanks.
>
> (define my-frame
>   (instantiate frame% () (label "Key event")))
>
> (define my-canvas%
>   (class canvas%
>     (override on-char)
>     (define on-char
>         (lambda (event)
>             (printf "~a~n" (send event get-key-code ))))
>     (super-instantiate ())))
>
> (define my-canvas
>   (instantiate my-canvas% () (parent my-frame) (min-width 200) 
> (min-height 100)))
>
> (send my-frame show #t)   ; CLICK IN THE FRAME :-( THEN enter some 
> keys...
>
>
(send my-canvas focus) should work.

Katsmall T. Wise, Esquire.