Radio Buttons
Car radios and some table radios have buttons
for selecting a radio station.
Only one station is selected at a time.
When one button is pushed in the
previous selection pops out.
The Swing class
JRadioButton
works the same way.
Radio buttons must be members of a
ButtonGroup.
Only one button of a button group is
selected at a time.
A constructor for JRadioButton is
as follows.
There are other constructors that may be useful
(see the Java documentation).
JRadioButton( String text, boolean selected )
The text is the words that next to the button.
If selected is true then this button
starts out selected.
Only one button of a button group may start out as selected.
JRadioButton is a child class of
JAbstractButton.
Radio buttons and push buttons have many methods
in common.
