java.awt
Class Checkbox

java.lang.Object   
  java.awt.Component   
      java.awt.Checkbox

All Implemented Interfaces:

ImageObserver , ItemSelectable , MenuContainer , Serializable , Accessible

public class Checkbox
extends Component   
implements ItemSelectable   , Accessible   

A check box is a graphical component that can be in either an "on" (true) or "off" (false) state. Clicking on a check box changes its state from "on" to "off," or from "off" to "on."

The following code example creates a set of check boxes in a grid layout:

 setLayout(new GridLayout(3, 1));
 add(new Checkbox("one", null, true));
 add(new Checkbox("two"));
 add(new Checkbox("three"));
 

This image depicts the check boxes and grid layout created by this code example:

The button labeled one is in the "on" state, and the other two are in the "off" state. In this example, which uses the GridLayout class, the states of the three check boxes are set independently.

Alternatively, several check boxes can be grouped together under the control of a single object, using the CheckboxGroup class. In a check box group, at most one button can be in the "on" state at any given time. Clicking on a check box to turn it on forces any other check box in the same group that is on into the "off" state.

Since:

JDK1.0

See Also:

GridLayout , CheckboxGroup , Serialized Form

Nested Class Summary

protected class

Checkbox.AccessibleAWTCheckbox This class implements accessibility support for the Checkbox class.

Nested classes/interfaces inherited from class java.awt.Component

Component.AccessibleAWTComponent , Component.BltBufferStrategy , Component.FlipBufferStrategy

Field Summary

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT , CENTER_ALIGNMENT , LEFT_ALIGNMENT , RIGHT_ALIGNMENT , TOP_ALIGNMENT

Fields inherited from interface java.awt.image.ImageObserver

ABORT , ALLBITS , ERROR , FRAMEBITS , HEIGHT , PROPERTIES , SOMEBITS , WIDTH

Constructor Summary

Checkbox ()
Creates a check box with an empty string for its label.

Checkbox (String label)
Creates a check box with the specified label.

Checkbox (String label, boolean state)
Creates a check box with the specified label and sets the specified state.

Checkbox (String label, boolean state, CheckboxGroup group)
Constructs a Checkbox with the specified label, set to the specified state, and in the specified check box group.

Checkbox (String label, CheckboxGroup group, boolean state)
Creates a check box with the specified label, in the specified check box group, and set to the specified state.

Method Summary

void	addItemListener (ItemListener l) Adds the specified item listener to receive item events from this check box.
void	addNotify () Creates the peer of the Checkbox.
AccessibleContext	getAccessibleContext () Gets the AccessibleContext associated with this Checkbox.
CheckboxGroup	getCheckboxGroup () Determines this check box's group.
ItemListener []	getItemListeners () Returns an array of all the item listeners registered on this checkbox.
String	getLabel () Gets the label of this check box.
<T extends EventListener > T[]	getListeners (Class <T> listenerType) Returns an array of all the objects currently registered as FooListeners upon this Checkbox.
Object []	getSelectedObjects () Returns an array (length 1) containing the checkbox label or null if the checkbox is not selected.
boolean	getState () Determines whether this check box is in the "on" or "off" state.
protected String	paramString () Returns a string representing the state of this Checkbox.
protected void	processEvent (AWTEvent e) Processes events on this check box.
protected void	processItemEvent (ItemEvent e) Processes item events occurring on this check box by dispatching them to any registered ItemListener objects.
void	removeItemListener (ItemListener l) Removes the specified item listener so that the item listener no longer receives item events from this check box.
void	setCheckboxGroup (CheckboxGroup g) Sets this check box's group to the specified check box group.
void	setLabel (String label) Sets this check box's label to be the string argument.
void	setState (boolean state) Sets the state of this check box to the specified state.

Methods inherited from class java.awt.Component

action , add , addComponentListener , addFocusListener , addHierarchyBoundsListener , addHierarchyListener , addInputMethodListener , addKeyListener , addMouseListener , addMouseMotionListener , addMouseWheelListener , addPropertyChangeListener , addPropertyChangeListener , applyComponentOrientation , areFocusTraversalKeysSet , bounds , checkImage , checkImage , coalesceEvents , contains , contains , createImage , createImage , createVolatileImage , createVolatileImage , deliverEvent , disable , disableEvents , dispatchEvent , doLayout , enable , enable , enableEvents , enableInputMethods , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , firePropertyChange , getAlignmentX , getAlignmentY , getBackground , getBounds , getBounds , getColorModel , getComponentAt , getComponentAt , getComponentListeners , getComponentOrientation , getCursor , getDropTarget , getFocusCycleRootAncestor , getFocusListeners , getFocusTraversalKeys , getFocusTraversalKeysEnabled , getFont , getFontMetrics , getForeground , getGraphics , getGraphicsConfiguration , getHeight , getHierarchyBoundsListeners , getHierarchyListeners , getIgnoreRepaint , getInputContext , getInputMethodListeners , getInputMethodRequests , getKeyListeners , getLocale , getLocation , getLocation , getLocationOnScreen , getMaximumSize , getMinimumSize , getMouseListeners , getMouseMotionListeners , getMousePosition , getMouseWheelListeners , getName , getParent , getPeer , getPreferredSize , getPropertyChangeListeners , getPropertyChangeListeners , getSize , getSize , getToolkit , getTreeLock , getWidth ,