[R-gui] [R Gui]Moving thru fields

[James Wettenhall]

 On Thu, 22 Apr 2004, Erin Hodgess wrote:

> Hello again!
> 
> I have several entry fields.
> I want to check each field as I go along
> Then I want to move to the next field.
> How to I move to the next field, please?
> 
> Thanks so much!
> 
> >From a sorely puzzled
> Erin
> mailto: hodgess at gator.uhd.edu
> 

Erin,

It depends what you mean by next.  If you mean next in the 
tab-order (i.e. when the user presses the 'Tab' key), I don't 
know how to do that.  But it might help you to define a 
list of tclVars and a list of widgets...

tclVarList <- list()
for (i in (1:NumEntryFields))
  tclVarList[[i]] <- tclVar("Initial value")

EntryList <- list()
for (i in (1:NumEntryFields))
  EntryList[[i]] <- tkentry(tt,textvariable=tclVarList[[i]])

Then moving to the next field as defined by the list shouldn't 
be too hard...

What about assigning callback functions to a list of widgets?  
Is it considered reasonable R coding style to have a list of 
functions?  I didn't think of this when I implemented a list of 
widgets, so I did something like this:

for (i in (1:NumWidgets))
  eval(parse(text=paste("onBrowse",i,
  " <- function() {onBrowse(",i,",)}",sep="")))

tkentry(...,command=eval(parse(text=paste("onBrowse",i,sep=""))),...)

The idea is that (unless I'm mistaken), a Tcl callback function 
for something like a button-press in R-Tcl/Tk shouldn't have any 
arguments, so here I used a function onBrowse1() with no 
arguments to call a function onBrowse(1), and onBrowse2() to
call onBrowse(2) etc.  Does that make sense?

Regards,
James


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James Wettenhall                                  Tel: (+61 3) 9345 2629
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