Widgets 3 : Radiobutton, Checkbutton

radiobutton

Radiobutton is an input where any one of many choices MUST be chosen. If one is chosen and another button is clicked, the last chosen will lose its state and the clicked button will be chosen. A graphic example(in HTML) is given below.

Choices 1 | 2 | 3

Some Options

-command COMMAND	Specifies a Tcl command to associate with the button. This command is typically invoked when mouse button 1 is released over the button window.
-variable VARIABLE	Specifies name of global variable to set to indicate whether or not this button is selected.
-value VALUE	Specifies value to store in the button's associated variable whenever this button is selected.

Syntax	Description	Example
path deselect	Deselects the checkbutton and sets the associated variable to its ``off'' value.	.rdb_m deselect
path select	Selects the checkbutton and sets the associated variable to its ``on'' value.	.rdb_m select

Example

#This function will be exected when the button is pushed
proc push_button {} {
	global age gender
	set name [.ent get]
	.txt insert end "$name\($gender\) is $age years old."
}

#Global Variables
set age 10
set gender "Male"
#GUI building
frame .frm_name
label .lab -text "Name:"
entry .ent
#Age
scale .scl -label "Age :" -orient h -digit 1 -from 10 -to 50 \
	-variable age -tickinterval 10

#Gender
frame .gender
label .lbl_gender -text "Sex "
radiobutton .gender.rdb_m -text "Male"   -variable gender -value "Male"
radiobutton .gender.rdb_f -text "Female" -variable gender -value "Female"
.gender.rdb_m select

button .but -text "Push Me" -command "push_button"

#Text Area
frame .textarea
text .txt -yscrollcommand ".srl_y set" -xscrollcommand ".srl_x set" \
	-width 40 -height 10
scrollbar .srl_y -command ".txt yview" -orient v
scrollbar .srl_x -command ".txt xview" -orient h

#Geometry Management
grid .frm_name -in . -row 1 -column 1 -columnspan 2
grid .lab -in .frm_name -row 1 -column 1
grid .ent -in .frm_name -row 1 -column 2
grid .scl -in . -row 2 -column 1 -columnspan 2
grid .gender -in . -row 3 -column 2
grid .lbl_gender -in .gender -row 1 -column 1
grid .gender.rdb_m -in .gender -row 1 -column 2
grid .gender.rdb_f -in .gender -row 1 -column 3
grid .but -in . -row 4 -column 1 -columnspan 2
grid .txt   -in .textarea -row 1 -column 1
grid .srl_y -in .textarea -row 1 -column 2 -sticky ns
grid .srl_x -in .textarea -row 2 -column 1 -sticky ew
grid .textarea -in . -row 5 -column 1 -columnspan 2

This time the program is subjected to even more change - the geometry manager is fully grid now. There is no instances of pack. You will find this necessary when the layout becomes more complicated. I hope you can stay with me in such trying times.

---

checkbutton

Checkbotton is a input with two options - Off or On - it has to be either one. The state can be changed by clicking on it. An example is shown below. check box
Some Options

-offvalue VALUE	Specifies value to store in the button's associated variable whenever this button is deselected. Defaults to ``0''.
-onvalue VALUE	Specifies value to store in the button's associated variable whenever this button is selected. Defaults to ``1''.
-command COMMAND	Specifies a Tcl command to associate with the button. This command is typically invoked when mouse button 1 is released over the button window.
-variable VARABLE	Specifies name of global variable to set to indicate whether or not this button is selected.

Syntax	Description	Example
path deselect	Deselects the checkbutton and sets the associated variable to its ``off'' value.	.chk deselect
path select	Selects the checkbutton and sets the associated variable to its ``on'' value.	.chk select
path toggle	Toggles the selection state of the button, redisplaying it and modifying its associated variable to reflect the new state.	.chk toggle

Example

#This function will be executed when the button is pushed
proc push_button {} {
	global age occupied gender
	set name [.ent get]
	.txt insert end "$name\($gender\) is $age years old and is "
	if { $occupied == 1 } {
		.txt insert end "occupied."
	} else {
		.txt insert end "unemployed."
	}
}

#Global Variables
set age 10
set occupied 1
set gender "Male"
#GUI building
frame .frm_name
label .lab -text "Name:"
entry .ent
#Age
scale .scl -label "Age :" -orient h -digit 1 -from 10 -to 50 \
	-variable age -tickinterval 10
checkbutton .chk -text "Occupied" -variable occupied
#Gender
frame .gender
label .lbl_gender -text "Sex "
radiobutton .gender.rdb_m -text "Male"   -variable gender -value "Male"
radiobutton .gender.rdb_f -text "Female" -variable gender -value "Female"
.gender.rdb_m select

button .but -text "Push Me" -command "push_button"

#Text Area
frame .textarea
text .txt -yscrollcommand ".srl_y set" -xscrollcommand ".srl_x set" \
	-width 40 -height 10
scrollbar .srl_y -command ".txt yview" -orient v
scrollbar .srl_x -command ".txt xview" -orient h

#Geometry Management
grid .frm_name -in . -row 1 -column 1 -columnspan 2
grid .lab -in .frm_name -row 1 -column 1
grid .ent -in .frm_name -row 1 -column 2
grid .scl -in . -row 2 -column 1
grid .chk -in . -row 2 -column 2
grid .gender -in . -row 3 -column 2
grid .lbl_gender -in .gender -row 1 -column 1
grid .gender.rdb_m -in .gender -row 1 -column 2
grid .gender.rdb_f -in .gender -row 1 -column 3
grid .but -in . -row 4 -column 1 -columnspan 2
grid .txt   -in .textarea -row 1 -column 1
grid .srl_y -in .textarea -row 1 -column 2 -sticky ns
grid .srl_x -in .textarea -row 2 -column 1 -sticky ew
grid .textarea -in . -row 5 -column 1 -columnspan 2