gcheckbox: constructor for checkbox widget
In jverzani/gWidgets2: Rewrite of gWidgets API for Simplified GUI Construction

Description Usage Arguments Value Note Examples

A checkbox widget is used to toggle the state of a labeled boolean variable. The main property of this widget is that state, not the label. This variable may be proxied in the usual way – with a box that indicates or check if TRUE – or through a toggle button.

Generic for toolkit dispatch

The change handler for GCheckbox is called when the value toggles. You can inpsect the current value in the callback to have an action based on the state.

The object state is referred to by svalue as a logical (TRUE for checked). The svalue<- method ensures the value is a logical vector of length 1.

The item to select is referred to by the [ method, with only the first element being used.

gcheckbox(text = "", checked = FALSE, use.togglebutton = FALSE,
  handler = NULL, action = NULL, container = NULL, ...,
  toolkit = guiToolkit())

.gcheckbox(toolkit, text, checked = FALSE, use.togglebutton = FALSE,
  handler = NULL, action = NULL, container = NULL, ...)

## S3 method for class 'GCheckbox'
addHandlerChanged(obj, handler, action = NULL, ...)

## S3 replacement method for class 'GCheckbox'
 svalue(obj, index=NULL, ...) <- value

## S3 replacement method for class 'GCheckbox'
 x[i, j, ...] <- value

`text`	label text
`checked`	is button selected
`use.togglebutton`	Use a toggle button (shows depressed) not a check box
`handler`	Callback called when toggle is changed.
`action`	passed to handler
`container`	parent container
`...`	passed to `add` method of container
`toolkit`	toolkit
`obj`	receiver object
`index`	ignored. Input is coerced to logical.
`value`	assignment value
`x`	checkbox object
`i`	item index
`j`	ignored

Returns an object of class GCheckbox.

The value is coerced to character, then only first element used for checkbox label

if(interactive()) {
  w <- gwindow("Selection widgets")
  g <- gvbox(cont=w)

  fl <- gformlayout(cont=g)
  gcheckbox("checkbox", checked=TRUE, cont=fl, label="checkbox")
  gradio(state.name[1:4], selected=2, horizontal=TRUE, cont=fl, label="gradio")
  gcheckboxgroup(state.name[1:4], horizontal=FALSE, cont=fl, label="checkbox group")

  bg <- ggroup(cont=g)
  gbutton("ok", cont=bg, handler=function(h,...) print(sapply(fl$children, svalue)))



}