JRadioButton component provides a visually selectable
* button with mutually exclusive behaviour within a ButtonGroup.
* A series of radio buttons can be used to provide options to the user,
* where the user can only select one of the available options. The state
* of the button is provided by the superclass, JToggleButton.
* JRadioButton adds the additional behaviour, that if two
* or more radio buttons are grouped together, the selection of one implies
* the deselection of the other buttons within the group.
*
*
* Buttons are grouped by adding each instance to a ButtonGroup.
* The existence of such a grouping is not reflected visually, so other means
* should be used to denote this. For instance, the grouped buttons can be placed
* within the same panel, possibly with an appropriate border to denote
* the connection between the components.
*
* @author Michael Koch (konqueror@gmx.de)
* @author Graydon Hoare (graydon@redhat.com)
* @author Andrew John Hughes (gnu_andrew@member.fsf.org)
* @see JToggleButton
* @see ButtonGroup
* @since 1.2
*/
public class JRadioButton extends JToggleButton
{
/**
* Compatible with Sun's JDK.
*/
private static final long serialVersionUID = 7751949583255506856L;
/**
* This class provides accessibility support for the toggle button.
*/
protected class AccessibleJRadioButton
extends AccessibleJToggleButton
{
private static final long serialVersionUID = 4850967637026120674L;
/**
* Constructor for the accessible toggle button.
*/
protected AccessibleJRadioButton()
{
/* Call the superclass to register for events */
super();
}
/**
* Returns the accessible role for the toggle button.
*
* @return An instance of AccessibleRole, describing
* the role of the toggle button.
*/
public AccessibleRole getAccessibleRole()
{
return AccessibleRole.RADIO_BUTTON;
}
}
/**
* Constructs an unselected radio button with no text or icon.
*/
public JRadioButton()
{
this(null, null, false);
}
/**
* Constructs a radio button using the labelling, state
* and icon specified by the supplied action.
*
* @param a the action to use to define the properties of the button.
*/
public JRadioButton(Action a)
{
this();
setAction(a);
}
/**
* Constructs an unselected radio button with the supplied icon
* and no text.
*
* @param icon the icon to use.
*/
public JRadioButton(Icon icon)
{
this(null, icon, false);
}
/**
* Constructs a radio button with the supplied icon and state.
*
* @param icon the icon to use.
* @param selected if true, the radio button is initially in the
* selected state. Otherwise, the button is unselected.
*/
public JRadioButton(Icon icon, boolean selected)
{
this(null, icon, selected);
}
/**
* Constructs an unselected radio button using the supplied text
* and no icon.
*
* @param text the text to use.
*/
public JRadioButton(String text)
{
this(text, null, false);
}
/**
* Constructs a radio button with the supplied text and state.
*
* @param text the text to use.
* @param selected if true, the radio button is initially in the
* selected state. Otherwise, the button is unselected.
*/
public JRadioButton(String text, boolean selected)
{
this(text, null, selected);
}
/**
* Constructs an unselected radio button with the supplied text
* and icon.
*
* @param text the text to use.
* @param icon the icon to use.
*/
public JRadioButton(String text, Icon icon)
{
this(text, icon, false);
}
/**
* Constructs a radio button with the supplied text, icon and state.
*
* @param text the text to use.
* @param icon the icon to use.
* @param selected if true, the radio button is initially in the
* selected state. Otherwise, the button is unselected.
*/
public JRadioButton(String text, Icon icon, boolean selected)
{
super(text, icon, selected);
setBorderPainted(false);
setHorizontalAlignment(LEADING);
}
/**
* Returns the accessible context for this JRadioButton,
* in the form of an instance of AccessibleJRadioButton.
* The context is created, if necessary.
*
* @return the associated context
*/
public AccessibleContext getAccessibleContext()
{
/* Create the context if this is the first request */
if (accessibleContext == null)
{
/* Create the context */
accessibleContext = new AccessibleJRadioButton();
}
return accessibleContext;
}
/**
* Returns a string specifying the name of the Look and Feel UI class
* that renders this component.
*
* @return the Look and Feel UI class for JRadioButtons
* as a String.
*/
public String getUIClassID()
{
return "RadioButtonUI";
}
/**
* Returns a string representation of this component for debugging use.
* Users should not depend on anything as regards the content or formatting
* of this string, except for the fact that the returned string may never be
* null (only empty).
*
* @return the component in String form for debugging.
*/
protected String paramString()
{
return super.paramString();
}
/**
* This method resets the radio button's UI delegate to the default UI for
* the current look and feel.
*/
public void updateUI()
{
/*
I can't see any difference between this and the superclass one,
but Sun reimplements it... there is no RadioButtonUI class for it
to be cast to.
*/
setUI((ButtonUI) UIManager.getUI(this));
}
}