Re: [racket-users] returning GUI elements in function?

[Travis Hinkelman]

It's funny how just knowing that there is an easy solution to a problem 
makes the problem easier to solve. My first thought about returning objects 
(prior to sending initial email) was that I would return all of the objects 
unnamed but then I was confused about how to specify the parents of the 
child objects in the `initialize-progress-bar` function. The code below 
solves my problem. As always, I welcome people sharing alternative ways to 
write the same code. 

#lang racket/gui

(define (initialize-progress-bar)
  (define frame (new frame%
 [label "Progress Bar"]
 [width 300]))

  (define hpane (new horizontal-pane%
 [parent frame]))

  (define gauge (new gauge%
 [label ""]
 [parent hpane]
 [range 100]))

  (define msg (new message%
   [parent hpane]
   [auto-resize #t]
   [label "0%"]))

  (send frame show #t)
  (values gauge msg))

(define (update-progress-bar new-value)
  (send the-gauge set-value new-value)
  (send the-msg set-label (string-append (~a new-value) "%")))

(define-values (the-gauge the-msg) (initialize-progress-bar))
(for ([i (in-range 1 101)])
  (sleep 0.05)
  (update-progress-bar i))




On Tuesday, July 9, 2019 at 1:05:03 AM UTC-7, Laurent wrote:
>
> There are several ways to solve this (including deriving classes), but the 
> simplest for you right now is probably to have `initialize-progress-bar' 
> return the gui widgets (in particular `gauge' and `msg'), assign the values 
> to `the-gauge' and `the-msg' (say) from the return values of 
> `(initialize-progress-bar)` call, and then pass these values to 
> `update-progress-bar' so that `gauge' and `msg' have the correct values 
> there.
>
> Does that make sense?
>
> On Tue, Jul 9, 2019 at 7:23 AM Travis Hinkelman  > wrote:
>
>> Hi All,
>>
>> I was playing around with creating a progress bar. The basic idea was 
>> straightforward.
>>
>> #lang racket/gui
>>
>> (define frame (new frame%
>>[label "Progress Bar"]
>>[width 300]))
>>
>> (define hpane (new horizontal-pane%
>>[parent frame]))
>>
>> (define gauge (new gauge%
>>[label ""]
>>[parent hpane]
>>[range 100]))
>>
>> (define msg (new message%
>>  [parent hpane]
>>  [auto-resize #t]
>>  [label "0%"]))
>>
>> (send frame show #t)
>>
>> (for ([i (in-range 1 101)])
>>   (sleep 0.05)
>>   (send gauge set-value i)
>>   (send msg set-label (string-append (~a i) "%")))
>>
>>
>> When I tried to take the next step of wrapping this up into a couple of 
>> functions, I was completely lost. I don't know how to initialize a frame 
>> with child elements by calling a function because all of the elements of 
>> the frame only exist in the function and not at the top-level (probably 
>> butchering the jargon here; hopefully it makes sense). I wasn't really sure 
>> where to look to learn more about doing such a thing. Here is some 
>> pseudocode to try to further illustrate my confusion.
>>
>> (define (initialize-progress-bar)
>>   ;; insert code that creates progress bar
>>   ;; i.e., from defining frame to sending frame in code above)
>>
>> (define (update-progress-bar new-value)
>>   (send gauge set-value new-value)
>>   (send msg set-label (string-append (~a new-value) "%")))
>>
>> (initialize-progress-bar)
>> (for ([i (in-range 1 101)])
>>   (sleep 0.05)
>>   (update-progress-bar i))
>>
>> Thanks,
>>
>> Travis
>>
>> -- 
>> You received this message because you are subscribed to the Google Groups 
>> "Racket Users" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to racket...@googlegroups.com .
>> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/racket-users/61a3ea75-d285-45d1-90d4-de569c441c8d%40googlegroups.com
>>  
>> 
>> .
>> For more options, visit https://groups.google.com/d/optout.
>>
>

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Re: [racket-users] returning GUI elements in function?

[Laurent]

There are several ways to solve this (including deriving classes), but the
simplest for you right now is probably to have `initialize-progress-bar'
return the gui widgets (in particular `gauge' and `msg'), assign the values
to `the-gauge' and `the-msg' (say) from the return values of
`(initialize-progress-bar)` call, and then pass these values to
`update-progress-bar' so that `gauge' and `msg' have the correct values
there.

Does that make sense?

On Tue, Jul 9, 2019 at 7:23 AM Travis Hinkelman 
wrote:

> Hi All,
>
> I was playing around with creating a progress bar. The basic idea was
> straightforward.
>
> #lang racket/gui
>
> (define frame (new frame%
>[label "Progress Bar"]
>[width 300]))
>
> (define hpane (new horizontal-pane%
>[parent frame]))
>
> (define gauge (new gauge%
>[label ""]
>[parent hpane]
>[range 100]))
>
> (define msg (new message%
>  [parent hpane]
>  [auto-resize #t]
>  [label "0%"]))
>
> (send frame show #t)
>
> (for ([i (in-range 1 101)])
>   (sleep 0.05)
>   (send gauge set-value i)
>   (send msg set-label (string-append (~a i) "%")))
>
>
> When I tried to take the next step of wrapping this up into a couple of
> functions, I was completely lost. I don't know how to initialize a frame
> with child elements by calling a function because all of the elements of
> the frame only exist in the function and not at the top-level (probably
> butchering the jargon here; hopefully it makes sense). I wasn't really sure
> where to look to learn more about doing such a thing. Here is some
> pseudocode to try to further illustrate my confusion.
>
> (define (initialize-progress-bar)
>   ;; insert code that creates progress bar
>   ;; i.e., from defining frame to sending frame in code above)
>
> (define (update-progress-bar new-value)
>   (send gauge set-value new-value)
>   (send msg set-label (string-append (~a new-value) "%")))
>
> (initialize-progress-bar)
> (for ([i (in-range 1 101)])
>   (sleep 0.05)
>   (update-progress-bar i))
>
> Thanks,
>
> Travis
>
> --
> You received this message because you are subscribed to the Google Groups
> "Racket Users" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to racket-users+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/racket-users/61a3ea75-d285-45d1-90d4-de569c441c8d%40googlegroups.com
> 
> .
> For more options, visit https://groups.google.com/d/optout.
>

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[racket-users] returning GUI elements in function?

[Travis Hinkelman]

Hi All,

I was playing around with creating a progress bar. The basic idea was 
straightforward.

#lang racket/gui

(define frame (new frame%
   [label "Progress Bar"]
   [width 300]))

(define hpane (new horizontal-pane%
   [parent frame]))

(define gauge (new gauge%
   [label ""]
   [parent hpane]
   [range 100]))

(define msg (new message%
 [parent hpane]
 [auto-resize #t]
 [label "0%"]))

(send frame show #t)

(for ([i (in-range 1 101)])
  (sleep 0.05)
  (send gauge set-value i)
  (send msg set-label (string-append (~a i) "%")))


When I tried to take the next step of wrapping this up into a couple of 
functions, I was completely lost. I don't know how to initialize a frame 
with child elements by calling a function because all of the elements of 
the frame only exist in the function and not at the top-level (probably 
butchering the jargon here; hopefully it makes sense). I wasn't really sure 
where to look to learn more about doing such a thing. Here is some 
pseudocode to try to further illustrate my confusion.

(define (initialize-progress-bar)
  ;; insert code that creates progress bar
  ;; i.e., from defining frame to sending frame in code above)

(define (update-progress-bar new-value)
  (send gauge set-value new-value)
  (send msg set-label (string-append (~a new-value) "%")))

(initialize-progress-bar)
(for ([i (in-range 1 101)])
  (sleep 0.05)
  (update-progress-bar i))

Thanks,

Travis

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