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\name{gcombobox}
\alias{gcombobox}
\alias{gdroplist}
\alias{[<-,gCombobox-method}
\title{Widgets to allow selection from a vector of items}
\description{
A combobox allows selection of a value from a list of items
using a popup menu. Additionally, the widget can combine a
text entry widget for user input outside of the pre-set list
of items. A combobox is useful for selection from a moderate
size of items (2-30, say). For smaller sets of items, a radio
button group is a possibility, for larger sets of items, a
scrollable (and perhaps searchable) table may be preferred.
}
\usage{
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())
}
\arguments{
\item{items}{ Vector of values to select from. This may also be a data frame, in which case the first column is the vector of values, the second (if present) indicates a stock icon to display with the item (not all toolkits), and the third (if present) will indicate a tooltip to display (not all toolkits). }
\item{selected}{ For gradio the initial selected value (as an index)
For a drop list, the first selected value. Use 0 to
leave blank}
\item{editable}{A logical indicating if the user can
add an entry to the list of available answers}
\item{coerce.with}{Apply this function to selected value before returning}
\item{handler}{Called when selection is changed}
\item{action}{Passed to handler when called.}
\item{container}{Optional container to attach widget to}
\item{\dots}{Passed to \code{add} method of container}
\item{toolkit}{Which GUI toolkit to use}
}
\details{
The initial \code{items} can be a vector or a data frame. Not
all tool kits do something with the extra columns in the data
frame.
The \code{svalue} method returns the selected value by
name. Assume the value is a character vector. Use the
\code{coerce.with} argument to return a value of a different
type. If the extra argument \code{index=TRUE} is specified,
the index of the selected value is given.
The \code{svalue<-} method can be used to set the selected
value. This is done my name or if the argument
\code{index=TRUE} is given by index. The value can be a data
frame, in which case the first column is used to match against
the current items.
The \code{"["} method refers to the vector defining the items.
The \code{"[<-"} method can be used to change the vector
defining the items.
The \code{"length"} method returns the number of items.
For \code{gcombobox} the argument \code{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
\code{svalue}. Use \code{coerce.with} to coerce this prior to returning.
}
% \value{}
% \references{}
% \author{}
% \note{}
\seealso{
A combobox is one of several ways to select a value of a set of items. See also
\code{\link{gcheckbox}},
\code{\link{gradio}},
\code{\link{gcheckboxgroup}}, and
\code{\link{gtable}}.
Methods for gComponent objects are detailed in \code{\link{gWidgets-methods}}.
Event Handlers are detailed in \code{\link{gWidgets-handlers}}.
}
\examples{
\dontrun{
flavors <- c("vanilla", "chocolate", "strawberry")
f <- function(h,...) print(
paste("Yum",
paste(svalue(h$obj),collapse=" and "),
sep = " "))
w <- gwindow("combobox example")
gp <- ggroup(container=w)
glabel("Favorite flavor:", container=gp)
cb <- gcombobox(flavors, editable=TRUE, container=gp, handler=f)
svalue(cb) <- "vanilla"
svalue(cb)
cbg[3] <- "raspberry"
}
}
\keyword{interface}% at least one, from doc/KEYWORDS
|
