rp.combo: A 'combo' for a panel

In rpanel: Simple Interactive Controls for R using the 'tcltk' Package

A ‘combo’ for a panel

Description

This function adds a ‘combobox’ to the panel. When an item is pressed, a variable is set and an action function is called.

Usage

rp.combo(panel, variable, prompt=NULL, vals, initval=vals[1], pos=NULL, action=I,
  foreground=NULL, background=NULL, font=NULL, editable=FALSE,
  parentname=deparse(substitute(panel)), name=paste("combo", .nc(), sep=""), ...) 

Arguments

panel	the panel in which the combobox should appear.
variable	the name of the variable whose value is set by the combobox.
prompt	the label for the combobox.
vals	the values of variable used by the combo.
initval	the initial value of variable (optional). The initial value can also be specified in the call to rp.control.
pos	the layout instructions. Please see the rp.pos example and help for full details.
action	the function which is called when an item is chosen.
foreground	colour of the text
background	colour of the text background
font	font to be used
editable	whether the combobox can be edited or not.
parentname	this specifies the widget inside which the combobox should appear.
name	name assigned to the combobox, used for disposing of the widget
...	...

Details

The function action should take one argument, which should be the panel to which the combobox is attached.

See rp.grid for details of the grid layout system.

This function makes use of the BWidget extension to the Tcl/Tk system. If Bwidget has not been installed on your system, download it from https://sourceforge.net/projects/tcllib/files/BWidget/ and expand the compressed file into a folder. On a Windows machine, this folder should then be copied into the folder containing the Tcl libraries that were installed as part of R. This may be in a location such as C:\Program Files\R\R-4.0.2\Tcl\lib (with an obvious change to the version number of R being used). On a Mac, the downloaded folder should be copied into the folder where the main Tcl package is located (note: not inside the Tcl folder but at the same level as the Tcl folder). This may be in a location such as /usr/local/lib.

Note that rp.listbox provides an alternative to rp.combo if the latter is unavailable.

Value

If the parameter panel is the panelname string the same string is returned. If the panel object is used the altered panel is assigned to both the calling level and panel's environment level.

Warning

The action function should return the panel. Without this assignment any widgets added or alterations made to panel parameters within the action function will be lost.

Note

Parameters parent and ... have been discontinued in version 1.1. Note that the argument previously named var has been renamed variable to avoid reserved word issues.

References

rpanel: Simple interactive controls for R functions using the tcltk package. Journal of Statistical Software, 17, issue 9.

See Also

rp.checkbox, rp.control

Examples

## Not run: 
   callback <- function(panel) {
      print(panel$option)
      panel
   }
   panel <- rp.control()
   rp.combo(panel, option, "Pick an option:", 
            c("Option1","Option2","Other options"), action=callback)

## End(Not run)

rpanel documentation built on Feb. 16, 2023, 10:37 p.m.