charvax.swing

Class ButtonGroup

Implemented Interfaces:
EventListener, ItemListener

public class ButtonGroup
extends java.lang.Object
implements ItemListener

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

Initially, all buttons in the group are unselected. Once any button in the group is selected, one button is always selected in the group.

Note that the ButtonGroup is a logical grouping, not a physical grouping. To create a button panel, you should still create a JPanel and add the JRadioButtons to it.

Constructor Summary

ButtonGroup()
Creates a new ButtonGroup

Method Summary

void
add(AbstractButton button_)
Adds the specified button to the group.
int
getButtonCount()
Returns the number of buttons in the ButtonGroup.
Enumeration
getElements()
Returns an Enumeration of all the buttons in this group.
AbstractButton
getSelection()
Get the selected radiobutton.
boolean
isSelected(AbstractButton button_)
Returns the selected value for the specified button.
void
itemStateChanged(ItemEvent e_)
Implements the ItemListener interface.
void
remove(AbstractButton button_)
Remove the specified button from the group.
void
setSelected(AbstractButton button_, boolean val_)
Sets the selected value for the specified button.

Constructor Details

ButtonGroup

public ButtonGroup()
Creates a new ButtonGroup

Method Details

add

public void add(AbstractButton button_)
Adds the specified button to the group.

getButtonCount

public int getButtonCount()
Returns the number of buttons in the ButtonGroup.

getElements

public Enumeration getElements()
Returns an Enumeration of all the buttons in this group.

getSelection

public AbstractButton getSelection()
Get the selected radiobutton. Returns null if no button is selected.

isSelected

public boolean isSelected(AbstractButton button_)
Returns the selected value for the specified button.

itemStateChanged

public void itemStateChanged(ItemEvent e_)
Implements the ItemListener interface. Listens for state changes from all the buttons in the group.
Specified by:
itemStateChanged in interface ItemListener

remove

public void remove(AbstractButton button_)
Remove the specified button from the group.

setSelected

public void setSelected(AbstractButton button_,
                        boolean val_)
Sets the selected value for the specified button. This method doesn't appear to make sense but it is present in the Swing version of ButtonGroup.