Class ButtonGroup

java.lang.Object

javax.swing.ButtonGroup

All Implemented Interfaces:

Serializable

public class ButtonGroup
extends Object
implements Serializable

This class is used to create a multiple-exclusion scope for a set of buttons. Creating a set of buttons with the same ButtonGroup object means that turning "on" one of those buttons turns off all other buttons in the group.

A ButtonGroup can be used with any set of objects that inherit from AbstractButton. Typically a button group contains instances of JRadioButton, JRadioButtonMenuItem, or JToggleButton. It wouldn't make sense to put an instance of JButton or JMenuItem in a button group because JButton and JMenuItem don't implement the selected state.

Initially, all buttons in the group are unselected.

For examples and further information on using button groups see How to Use Radio Buttons, a section in The Java Tutorial.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans has been added to the java.beans package. Please see XMLEncoder.

Since:

1.2

Field Summary

Fields

Modifier and Type	Field	Description
protected Vector<AbstractButton>	buttons	The list of buttons participating in this group.

Constructor Summary

Constructors

Constructor	Description
ButtonGroup()	Creates a new ButtonGroup.

Method Summary

Modifier and Type	Method	Description
void	add(AbstractButton b)	Adds the button to the group.
void	clearSelection()	Clears the selection such that none of the buttons in the ButtonGroup are selected.
int	getButtonCount()	Returns the number of buttons in the group.
Enumeration<AbstractButton>	getElements()	Returns all the buttons that are participating in this group.
ButtonModel	getSelection()	Returns the model of the selected button.
boolean	isSelected(ButtonModel m)	Returns whether a ButtonModel is selected.
void	remove(AbstractButton b)	Removes the button from the group.
void	setSelected(ButtonModel m, boolean b)	Sets the selected value for the ButtonModel.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Field Details

buttons

protected Vector<AbstractButton> buttons

The list of buttons participating in this group.

Constructor Details

ButtonGroup

public ButtonGroup()

Creates a new ButtonGroup.

Method Details

add

public void add(AbstractButton b)

Adds the button to the group.

Parameters:

b - the button to be added

remove

public void remove(AbstractButton b)

Removes the button from the group.

Parameters:

b - the button to be removed

clearSelection

public void clearSelection()

Clears the selection such that none of the buttons in the ButtonGroup are selected.

Since:

1.6

getElements

public Enumeration<AbstractButton> getElements()

Returns all the buttons that are participating in this group.

Returns:

an Enumeration of the buttons in this group

getSelection

public ButtonModel getSelection()

Returns the model of the selected button.

Returns:

the selected button model

setSelected

public void setSelected(ButtonModel m,
 boolean b)

Sets the selected value for the ButtonModel. Only one button in the group may be selected at a time.

Parameters:

m - the ButtonModel

b - true if this button is to be selected, otherwise false

isSelected

public boolean isSelected(ButtonModel m)

Returns whether a ButtonModel is selected.

Parameters:

m - an instance of ButtonModel

Returns:

true if the button is selected, otherwise returns false

getButtonCount

public int getButtonCount()

Returns the number of buttons in the group.

Returns:

the button count

Since:

1.3