RADIOBUTTON(9) RADIOBUTTON(9)
NAME
radiobutton - Create and manipulate radiobutton widgets
SYNOPSIS
radiobutton pathName ?options?
STANDARD OPTIONS
-activebackground -disabledcolor -justify
-activeforeground -font -relief
-anchor -foreground -takefocus
-background -highlightcolor -text
-bitmap -highlightthickness -underline
-borderwidth -image
WIDGET-SPECIFIC OPTIONS
-command command
Specifies a Tk command to associate with the button.
This command is typically invoked when mouse button 1
is released over the button window. The button's glo-
bal variable (-variable option) will be updated before
the command is invoked.
-height dist
Specifies a desired height for the button. If this
option isn't specified, the button's desired height is
computed from the size of the image or bitmap or text
being displayed in it.
-indicatoron boolean
Specifies whether or not the indicator should be drawn.
If false, the relief option is ignored and the widget's
relief is always sunken if the widget is selected and
raised otherwise.
-selectcolor colour
Specifies a background colour to use when the button is
selected. If indicatoron is true, the colour applies
to the indicator. If indicatoron is false, this colour
is used as the background for the entire widget, in
place of background or activebackground, whenever the
widget is selected. If specified as an empty string,
no special colour is used for displaying when the wid-
get is selected.
-state state
Specifies one of three states for the radiobutton:
normal, active, or disabled. In normal state the
radiobutton is displayed using the foreground and back-
ground options. The active state is typically used
when the pointer is over the radiobutton. In active
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state the radiobutton is displayed using the active-
foreground and activebackground options. Disabled
state means that the radiobutton should be insensitive:
the default bindings will refuse to activate the widget
and will ignore mouse button presses. In this state
the disabledcolor and background options determine how
the radiobutton is displayed.
-value string
Specifies value to store in the button's associated
variable whenever this button is selected.
-variable string
Specifies name of global variable to set whenever this
button is selected. Changes in this variable also
cause the button to select or deselect itself.
Defaults to the value selectedButton.
-width dist
Specifies a desired width for the button. If this
option isn't specified, the button's desired width is
computed from the size of the image or bitmap or text
being displayed in it.
DESCRIPTION
The radiobutton command creates a new window (given by the
pathName argument) and makes it into a radiobutton widget.
Additional options, described above, may be specified on the
command line to configure aspects of the radiobutton such as
its colours, font, text, and initial relief. The radiobut-
ton command returns its pathName argument. At the time this
command is invoked, there must not exist a window named
pathName.
A radiobutton is a widget that displays a textual string,
bitmap or image and a circle called an indicator. If text
is displayed, it must all be in a single font, but it can
occupy multiple lines on the screen (if it contains new-
lines) and one of the characters may optionally be under-
lined using the underline option. A radiobutton has all of
the behaviour of a simple button: it can display itself in
either of three different ways, according to the state
option; it can be made to appear raised, sunken, or flat;
and it invokes a Tk command whenever mouse button 1 is
clicked over the check button.
In addition, radiobuttons can be selected. If a radiobutton
is selected, the indicator is normally drawn as a circle
containing a disc (possibly in a special colour), and a Tk
variable associated with the radiobutton is set to a partic-
ular value. If the radiobutton is not selected, the indica-
tor is drawn as an empty circle. Typically, several
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RADIOBUTTON(9) RADIOBUTTON(9)
radiobuttons share a single variable and the value of the
variable indicates which radiobutton is to be selected.
When a radiobutton is selected it sets the value of the
variable to indicate that fact; each radiobutton also moni-
tors the value of the variable and automatically selects and
deselects itself when the variable's value changes. By
default the variable selectedButton is used; its contents
give the name of the button that is selected, or the empty
string if no button associated with that variable is
selected. The name of the variable for a radiobutton, plus
the variable to be stored into it, may be modified with
options on the command line. Configuration options may also
be used to modify the way the indicator is displayed (or
whether it is displayed at all). By default a radiobutton
is configured to select itself on button clicks.
WIDGET COMMAND
The radiobutton command creates a new Tk command whose name
is pathName. This command may be used to invoke various
operations on the widget. It has the following general
form:
pathName option ?arg arg ...?
Option and the args determine the exact behaviour of the
command. The following commands are possible for radiobut-
ton widgets:
pathName cget option
Returns the current value of the configuration option
given by option. Option may have any of the values
accepted by the radiobutton command.
pathName configure ?option? ?value option value ...?
Query or modify the configuration options of the wid-
get. If no option is specified, returns a list of all
of the available options for pathName. If one or more
option-value pairs are specified, the command modifies
the given widget option(s) to have the given value(s);
in this case the command returns an empty string.
Option may have any of the values accepted by the
radiobutton command.
pathName deselect
Deselects the radiobutton and sets the associated vari-
able to an empty string. If this radiobutton was not
currently selected, the command has no effect.
pathName invoke
Does just what would have happened if the user invoked
the radiobutton with the mouse: selects the button and
invokes its associated Tk command, if there is one.
The return value is the return value from the Tk com-
mand, or an empty string if there is no command
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RADIOBUTTON(9) RADIOBUTTON(9)
associated with the radiobutton. This command is
ignored if the radiobutton's state is disabled.
pathName select
Selects the radiobutton and sets the associated vari-
able to the value corresponding to this widget.
BINDINGS
Tk automatically creates bindings for radiobuttons that give
them the following default behaviour:
[1] The radiobutton activates whenever the mouse passes
over it and deactivates whenever the mouse leaves the
radiobutton.
[2] When mouse button 1 is pressed over a radiobutton it is
invoked (it becomes selected and the command associated
with the button is invoked, if there is one).
If the radiobutton's state is disabled then none of the
above actions occur: the radiobutton is completely non-
responsive.
The behaviour of radiobuttons can be changed by defining new
bindings for individual widgets.
SEE ALSO
button(9), checkbutton(9), choicebutton(9), options(9),
types(9)
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