# The scrollable frame

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This example shows a scrollable frame (from the BWidget package). This is useful if you have an unknown number of entry widgets on a dialog and you don’t know whether they will fit in a normal-sized dialog.

The BWidget package is not included in the minimal installation of Tcl/Tk which comes with R. You will have to install it separately.

library(tcltk2)
tclRequire("BWidget")
tt <- tktoplevel()
tkpack(tklabel(tt, text = "This is not part of the scrollable frame"))
sw <- tkwidget(tt, "ScrolledWindow", relief = "sunken", borderwidth = 2)
sf <- tkwidget(sw, "ScrollableFrame")
tkcmd(sw, "setwidget", sf)
subfID <- tclvalue(tkcmd(sf, "getframe"))
lab <- tkcmd("label", paste0(subfID, ".lab"),
text = "This is a Scrollable Frame")
tkpack(lab)
entryList <- list()
for (i in (1:20)) {
entryList[[i]] <- tkcmd("entry", paste(subfID, i, sep = "."), width = 50)
tkpack(entryList[[i]], fill = "x", pady = 4)
tkbind(entryList[[i]], "<FocusIn>",
function() tkcmd(sf, "see", entryList[[i]]))
tkinsert(entryList[[i]], "end", paste("Text field", i))
}
tkpack(sw, fill = "both", expand = "yes")

The R code above produces a window with an area that can be scrolled up and down and that contains the 20 entries.