gradio: Radio button group widget

Description

A radio group allows the user to select one value from a set of items. The items may be displayed horizontally or vertically.

Usage

gradio(items, selected = 1, horizontal = FALSE, handler
= NULL, action = NULL, container = NULL, ..., toolkit = guiToolkit())

Arguments

items

Vector of values to select from

selected

The initial selected value (as an index). Radio groups must have a selection

horizontal

A logical specifying the layout for gradio

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

The svalue<- method can be used to set the selected value. One can specify the value by name or by index if index=TRUE is specified.

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

The "[<-" method can be used to change the vector defining the items.

The "length" method returns the number of items.

Examples

Run this code

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

  w <- gwindow("Radio example", visible=FALSE)
  gp <- ggroup(container=w)
  glabel("Favorite flavor:",container=gp, anchor=c(0,1))
  rb <- gradio(flavors, container=gp)
  addHandlerClicked(rb, handler=function(h,..) {
   cat(sprintf("You picked %s\n", svalue(h$obj)))
  })
  visible(w) <- TRUE
  
  betterFlavors <- c("coffee", "mint chip")
  rb[] <- betterFlavors 
  rb[] <- c(betterFlavors, "chocolate") # some toolkits don't allow change of length
  
  rb[3] <- "mango sorbet" ## can change a label name

  ## set values
  svalue(rb) <- "coffee"  ## by name
  svalue(rb, index=TRUE) <- 1  ## by index

  ## get selected values
  svalue(rb)
  svalue(rb, index=TRUE)

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