- java.lang.Object
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- java.awt.Component
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- java.awt.Checkbox
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- 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 theGridLayout
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:
- 1.0
- See Also:
GridLayout
,CheckboxGroup
, Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class Description protected class
Checkbox.AccessibleAWTCheckbox
This class implements accessibility support for theCheckbox
class.-
Nested classes/interfaces declared in class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
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Field Summary
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Fields declared in class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
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Fields declared in interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
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Constructor Summary
Constructors Constructor Description 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.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description 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 asFooListener
s upon thisCheckbox
.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 thisCheckbox
.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 registeredItemListener
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 declared in 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, getBaseline, getBaselineResizeBehavior, 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, getPreferredSize, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, minimumSize, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paint, paintAll, postEvent, preferredSize, prepareImage, prepareImage, print, printAll, processComponentEvent, processFocusEvent,
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