A gWidgets Example - Using windows, groups, labels, text and password boxes, buttons and events in R

A gWidget Example - Using windows, groups, labels, text and password boxes, buttons and events in R

jbytecode

August 20, 2013

In this entry, a short example for using gWidgets is given. gWidgets is a package for creating GUI’s in R.

Our example shows a GUI window with width = 400 and height = 400. Window is created by gwindow function. Components are located by rows. Rows are handled by ggroup function. ggroup must take a container as a parameter. In this logic, lbl_username and txt_username are childs of row1 which is child of gwindow.

Any text field can act as a password field by using visible¡- function.

visible(txt_password) <- FALSE

So, the object txt_password is now hiding characters by * characters. Finally, the method addHandlerClicked links an object to a function for click event. In our example, btn_login is linked to do_login function. When btn_login clicked, a message is written. The source code of the complete example is given below.

 
1# Loading required packages 
2require("gWidgets") 
3require("gWidgetstcltk") 
4 
5# main window 
6main <- gwindow(title="Login␣Window", 
7                width=400, 
8                height=400) 
9 
10# a row and components 
11row1 <- ggroup(container=main) 
12lbl_username <- glabel(container=row1, text="Username:␣") 
13txt_username <- gedit(container=row1) 
14 
15 
16# a row and components 
17row2 <- ggroup(container=main) 
18lbl_password <- glabel(container=row2, text="Password:␣") 
19txt_password <- gedit(container=row2) 
20 
21# any text in txt_password will be show with * character 
22visible(txt_password) <- FALSE 
23 
24# a row for button 
25row3 <- ggroup(container=main) 
26btn_login <- gbutton(container=row3, 
27                        text="Login") 
28btn_register <- gbutton(container=row3, 
29                        text="Register") 
30 
31 
32# Event handler for login button 
33do_login <- function(obj){ 
34        cat("Login␣with␣",svalue(txt_username),"\n") 
35} 
36 
37# Event handler for register button 
38do_register <- function(obj){ 
39        cat("Register␣with␣", svalue(txt_username),"\n") 
40} 
41 
42 
43# Registering Events 
44addHandlerClicked ( btn_login, do_login) 
45addHandlerClicked ( btn_register, do_register)