Buttonhandler does not work when empty field

Started by hotcore, August 10, 2012, 05:00:14 AM

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having written my first little newlisp app after lurking now and then on this forum, I have a small problem.

In the code below, when I do NOT enter anything in the input field and push the f->c button, the buttonhandler seems not to work.

The println is not executed! What am I doing wrong?

Thx, Arie

(load (append (env "NEWLISPDIR") "/guiserver.lsp"))

(define (f2c x)
(set 'y (float x nil))
(println "y=" y ";")
(y (string (div (sub y 32.0) 1.8)))
(true "enter a number")

(define (c2f x)
(set 'y (float x nil))
(y (string (add (mul y 1.8) 32.0)))
(true "enter a number")


(gs:frame 'Convert 300 300 270 120 "Convert Fahrenheit & Celsius")
(gs:set-resizable 'Convert nil)
(gs:set-border-layout 'Convert)

(gs:panel 'Input)
(gs:set-flow-layout 'Input "left")
(gs:label 'Inlab "Input value:" "left" 44)
(gs:text-field 'Inval 'text-handler 20)
(gs:add-to 'Input 'Inlab 'Inval)

(gs:panel 'Output)
(gs:set-flow-layout 'Output "left")
(gs:label 'Outlab "Output value:" "left" 35)
(gs:label 'Outval "")
(gs:add-to 'Output 'Outlab 'Outval)

(gs:panel 'Button)
(gs:set-grid-layout 'Button 1 2)
(gs:button 'f2c 'button-handler "Convert F -> C")
(gs:button 'c2f 'button-handler "Convert C -> F")
(gs:add-to 'Button 'f2c 'c2f)

(gs:add-to 'Convert 'Input "north" 'Output "center" 'Button "south")

(gs:set-visible 'Convert true)

(define (text-handler id value) nil)

(define (button-handler id value)
((= id "MAIN:f2c")
(gs:set-text 'Outval (f2c (gs:get-text 'Inval))))
((= id "MAIN:c2f")
(gs:set-text 'Outval (c2f (gs:get-text 'Inval))))
(gs:set-text 'Outval "invalid id detected"))



It seems that, when you don't do a set-text for a text-field (or fill it in in the form manually) that get-text for that text-field gets stuck somehow.

The same behavior occurs when you empty the text-field at some stage (delete all chars in it).

Any ideas?




Initialize the text field to some inital non-empty string, e.g. a space:

(gs:text-field 'Inval 'text-handler 20)
(gs:set-text 'Inval  " ")

I also would increase the height of the Convert frame from 270 to 400 when on Mac OSX for the textfield not to be squished.


Thanks Lutz!

I already tried that. But when the user empties the field, the same problem will still occur ...

Is there a way (apart from get-text) to see if a field is in such an uninitialized state?

BTW many thanks for this wonderful language!


The relevant function in the text-field widget in guiserver.jar was not handling empty text correctly when text was requested via gs:get-text.

This is now fixed in version 1.47 of Guiserver available here:

http://www.newlisp.org/downloads/development/inprogress/guiserver.jar">http://www.newlisp.org/downloads/develo ... server.jar">http://www.newlisp.org/downloads/development/inprogress/guiserver.jar

Ps: there will also be a newLISP maintenance release 10.4.4 in September, where the fixed guiserver.jar will be included.


Wow, Lutz you are a genius ;-)

Thanks a lot for the quick fix!