multiple comboboxes in R using tcltk

Question

I have been trying to define multiple combo boxes in R using the tcltk package but to no avail. I am using the below code. My inspiration was here, however I can't seem to just label them comboBox1, comboBox2, etc... so I decided to try and set their output values into a vector... but their output values don't make any sense to me... any ideas out there?

many thanks

require(tcltk)
tclRequire("BWidget")
tt <- tktoplevel()
tkgrid(tklabel(tt,text="What's your favorite fruits?"))
fruit <- c("Apple","Orange","Banana","Pear")
num <- c(0:3)
num.fruit <- cbind(num, fruit)
#####1st box
comboBox <- tkwidget(tt,"ComboBox",editable=FALSE,values=num.fruit[,2])
tkgrid(comboBox)
Cbox1<- comboBox
tkfocus(tt)

######2nd box

comboBox <- tkwidget(tt,"ComboBox",editable=FALSE,values=num.fruit[,2])
tkgrid(comboBox)
Cbox2 <- comboBox
###

##preliminary wrap-ip to pass to OnOK function
pref1 <- tcl(Cbox1,"getvalue")
pref2 <- tcl(Cbox2,"getvalue")

  Prefs <- c(pref1,pref2)
######action on OK button
OnOK <- function()
{
    fruitChoice <- fruits[as.numeric(tclvalue(tcl(Prefs,"getvalue")))+1]

    tkdestroy(tt)
    msg <- paste("Good choice! ",fruitChoice,"s are delicious!",sep="")
    tkmessageBox(title="Fruit Choice",message=msg)

}
OK.but <-tkbutton(tt,text="   OK   ",command=OnOK)
tkgrid(OK.but)
tkfocus(tt)

Answer 1

Why don't you just use ttkcombobox?

require(tcltk)
tt <- tktoplevel()
tkwm.title(tt, "Fruits!")
tkwm.geometry(tt, "200x150+300+300") 

onOK <- function()
    {
    fav <- tclvalue(favFruit)
    worst <- tclvalue(worstFruit)

    if (fav != "Choose one")
        tkmessageBox(title="Favorite fruit", message = paste("Your favorite fruit is", fav))
    if (worst != "Choose one")
        tkmessageBox(title="Worst fruit", message = paste("The fruit you like the least is", worst))

    if (fav == "Choose one" & worst == "Choose one")
        tkmessageBox(title="Well...", message = "Select a fruit!")
    }

label1 <- tklabel(tt, text="What's your favorite fruit?")
label2 <- tklabel(tt, text="What fruit you like the least?")

fruits <- c("Choose one", "Apple", "Orange", "Banana", "Pear")
# Default selections for the two combo boxes
favFruit <- tclVar("Choose one")
worstFruit <- tclVar("Choose one")

# 1st box
combo.1 <- ttkcombobox(tt, values=fruits, textvariable=favFruit, state="readonly") 
# 2nd box
combo.2 <- ttkcombobox(tt, values=fruits, textvariable=worstFruit, state="readonly") 
# If you need to do something when the user changes selection just use
# tkbind(combo.1, "<<ComboboxSelected>>", functionname)

OK.but <- tkbutton(tt,text="   OK   ", command = onOK)

tkpack(label1, combo.1)
tkpack(label2, combo.2)
tkpack(OK.but)

tkfocus(tt)

PS: personally, I abandoned tcltk in favour of RGtk2, much more flexible in my opinion and you can design interfaces visually using Glade Interface Designer

Answer 2

If you don't want to get too involved with tcltk, you might find gWidgets easier to work with.

library(gWidgets)
options(guiToolkit="tcltk") ## or RGtk2 or Qt

w <- gwindow("Multiple comboboxes")
tbl <- glayout(cont=w, horizontal=FALSE)

fruit <- c("Apple","Orange","Banana","Pear")


tbl[1,1] <- "Favorite fuits"
tbl[1,2] <- (cb1 <- gcombobox(fruit, cont=tbl))

tbl[2,1] <- "Other fruit?"
tbl[2,2] <- (cb2 <- gcombobox(fruit, cont=tbl))

tbl[3,2] <- (b <- gbutton("Ok", cont=tbl))

addHandlerClicked(b, handler=function(h,...) {
  cat(sprintf("You picked %s and %s\n", svalue(cb1), svalue(cb2)))
})