I was thinking I'd eventually need more than two states, and so hadn't considered a checkbox. Happily, today's problem only requires the two states, and so a little rework has yielded what looks to be a better solution. Thanks for the suggestion.
On Tue, Feb 21, 2012 at 10:53 AM, Matthew Flatt <mfl...@cs.utah.edu> wrote: > The idea of `set-state-normal' and `set-state-selected' sounds like a > `check-box%' rather than a `button%'. > > Otherwise, there's no way to change the background color of a `button%' > instance. Classes like `button%' correspond to platform-specific GUI > widgets that typically either don't support or strongly discourage the > possibility of changing a button's background (because button colors > are normally determined by a theme). You can create a `canvas%' that > draws a custom button image, in which case you have complete control > over how the button looks and reacts, but there isn't much of an > in-between level of customization in the current toolkit. > > At Tue, 21 Feb 2012 00:25:52 -0700, Kieron Hardy wrote: > > Hi all, > > > > How do I change the background color (and/or style of border etc.) of a > GUI > > button? Given the code below, what should I put in the set-state-x > methods > > to indicate a difference between a normal and selected button? > > > > Also any comments on program style and/or substance are appreciated (I > > apologize in advance if the layout offends). > > > > Cheers, > > > > Kieron. > > > > **** > > > > #lang racket/gui > > > > (define color-button% > > (class button% > > (inherit refresh) > > > > (define toggle > > (let ([f #f]) > > (lambda () > > (set! f (not f)) > > f > > ) > > ) > > ) > > > > (define (set-state-normal) > > (printf "color-button%: set-state-normal:\n") > > ; ??? ; set background color to normal > > (refresh) > > ) > > > > (define (set-state-selected) > > (printf "color-button%: set-state-selected:\n") > > ; ??? ; set background color to red > > (refresh) > > ) > > > > (define click-callback > > (lambda (button control-event) > > (printf "color-button%: click-callback:\n") > > (if (toggle) > > (set-state-selected) > > (set-state-normal) > > ) > > ) > > ) > > > > (super-new (callback click-callback)) > > > > ) > > ) > > > > (define f (new frame% > > [label "Colored Button"] > > [min-width 100] > > [min-height 200] > > ) > > ) > > > > (define b (new color-button% > > [parent f] > > [label "push me"] > > ) > > ) > > > > (send f show #t) > > ____________________ > > Racket Users list: > > http://lists.racket-lang.org/users >
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