gWidgets (version 0.0-27)

gradio: Widgets to allow selection from a vector of items

Description

Widgets to select one (or several) from a given vector of items. These are a radio group where all values are shown at once, but only one may be selected; a checkbox group where more than one may be selected; and a combo box (or droplist) where initially only a single value is shown, and the others are a mouse click away,

Usage

gradio(items, selected = 1, horizontal = FALSE, handler
= NULL, action = NULL, container = NULL, ..., toolkit = guiToolkit())
gcombobox(items, selected = 1, editable = FALSE, coerce.with=NULL, handler = NULL, 
    action = NULL, container = NULL, ..., toolkit = guiToolkit())
gdroplist(items, selected = 1, editable = FALSE, coerce.with=NULL, handler = NULL, 
    action = NULL, container = NULL, ..., toolkit = guiToolkit()) 
gcheckboxgroup(items, checked = FALSE,  horizontal = FALSE, 
    handler = NULL, action = NULL, container = NULL, ..., toolkit = guiToolkit())

Arguments

items

Vector of values to select from

selected

For gradio the initial selected value (as an index) For a drop list, the first selected value. Use 0 to leave blank

checked

For gcheckboxgroup a logical vector of initial values.

editable

For gdroplist, a logical indicating if the user can add an entry to the list of available answers

coerce.with

Apply this function to selected value before returning

horizontal

A logical specifying the layout for gradio and gcheckboxgroup

handler

Called when selection is changed

action

Passed to handler when called.

container

Optional container to attach widget to

...

Passed to add method of container

toolkit

Which GUI toolkit to use

Details

The basic methods all work similarly for these three widgets.

The svalue method returns the selected values by name. If the extra argument index=TRUE is specified, the indices of the selected values is given.

The svalue<- method can be used to set the selected value.

The "[" method refers to the vector defining the items.

The "[<-" method can be used to change the vector defining the items. The length will most likely need to be the same.

The "length" method returns the number of items. For gdroplist the argument editable=TRUE adds a text-edit box where the user can type in a selection. By default this value is returned as a character by svalue. Use coerce.with to coerce this prior to returning.

Examples

flavors <- c("vanilla", "chocolate", "strawberry")

  f <- function(h,...) print(
      paste("Yum",
      paste(svalue(h$obj),collapse=" and "),
      sep = " "))

  w <- gwindow("Radio example")
  gp <- ggroup(container=w)
  glabel("Favorite flavor:",cont=gp)
  rb <- gradio(flavors, cont=gp, handler = f)

  w <- gwindow("combobox example")
  gp <- ggroup(container=w)
  glabel("Favorite flavor:", cont=gp)
  gcombobox(flavors, editable=TRUE, cont=gp, handler=f)

  w <- gwindow("checkbox example")
  gp <- ggroup(container=w)
  glabel("Favorite flavors:",cont=gp)
  cb <- gcheckboxgroup(flavors, cont=gp, handler=f)

  svalue(cbg) <- c(TRUE, FALSE, TRUE)
  svalue(cbg)
  cbg[3] <- "raspberry"