Java™ Platform
Standard Ed. 6

javax.swing
Class JPanel

java.lang.Object
  extended by java.awt.Component
      extended by java.awt.Container
          extended by javax.swing.JComponent
              extended by javax.swing.JPanel
All Implemented Interfaces:
ImageObserver, MenuContainer, Serializable, Accessible
Direct Known Subclasses:
AbstractColorChooserPanel, JSpinner.DefaultEditor

public class JPanel
extends JComponent
implements Accessible

JPanel is a generic lightweight container. For examples and task-oriented documentation for JPanel, see How to Use Panels, a section in The Java Tutorial.

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

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 JavaBeansTM has been added to the java.beans package. Please see XMLEncoder.


Nested Class Summary
protected  class JPanel.AccessibleJPanel
          This class implements accessibility support for the JPanel class.
 
Nested classes/interfaces inherited from class javax.swing.JComponent
JComponent.AccessibleJComponent
 
Nested classes/interfaces inherited from class java.awt.Container
Container.AccessibleAWTContainer
 
Nested classes/interfaces inherited from class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
 
Field Summary
 
Fields inherited from class javax.swing.JComponent
accessibleContext, listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW
 
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
JPanel()
          Creates a new JPanel with a double buffer and a flow layout.
JPanel(boolean isDoubleBuffered)
          Creates a new JPanel with FlowLayout and the specified buffering strategy.
JPanel(LayoutManager layout)
          Create a new buffered JPanel with the specified layout manager
JPanel(LayoutManager layout, boolean isDoubleBuffered)
          Creates a new JPanel with the specified layout manager and buffering strategy.
 
Method Summary
 AccessibleContext getAccessibleContext()
          Gets the AccessibleContext associated with this JPanel.
 PanelUI getUI()
          Returns the look and feel (L&F) object that renders this component.
 String getUIClassID()
          Returns a string that specifies the name of the L&F class that renders this component.
protected  String paramString()
          Returns a string representation of this JPanel.
 void setUI(PanelUI ui)
          Sets the look and feel (L&F) object that renders this component.
 void updateUI()
          Resets the UI property with a value from the current look and feel.
 
Methods inherited from class javax.swing.JComponent
addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update
 
Methods inherited from class java.awt.Container
add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusBackward, transferFocusDownCycle, validate, validateTree
 
Methods inherited from class java.awt.Component
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusUpCycle
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

JPanel

public JPanel(LayoutManager layout,
              boolean isDoubleBuffered)
Creates a new JPanel with the specified layout manager and buffering strategy.

Parameters:
layout - the LayoutManager to use
isDoubleBuffered - a boolean, true for double-buffering, which uses additional memory space to achieve fast, flicker-free updates

JPanel

public JPanel(LayoutManager layout)
Create a new buffered JPanel with the specified layout manager

Parameters:
layout - the LayoutManager to use

JPanel

public JPanel(boolean isDoubleBuffered)
Creates a new JPanel with FlowLayout and the specified buffering strategy. If isDoubleBuffered is true, the JPanel will use a double buffer.

Parameters:
isDoubleBuffered - a boolean, true for double-buffering, which uses additional memory space to achieve fast, flicker-free updates

JPanel

public JPanel()
Creates a new JPanel with a double buffer and a flow layout.

Method Detail

updateUI

public void updateUI()
Resets the UI property with a value from the current look and feel.

Overrides:
updateUI in class JComponent
See Also:
JComponent.updateUI()

getUI

public PanelUI getUI()
Returns the look and feel (L&F) object that renders this component.

Returns:
the PanelUI object that renders this component
Since:
1.4

setUI

public void setUI(PanelUI ui)
Sets the look and feel (L&F) object that renders this component.

Parameters:
ui - the PanelUI L&F object
Since:
1.4
See Also:
UIDefaults.getUI(javax.swing.JComponent)

getUIClassID

public String getUIClassID()
Returns a string that specifies the name of the L&F class that renders this component.

Overrides:
getUIClassID in class JComponent
Returns:
"PanelUI"
See Also:
JComponent.getUIClassID(), UIDefaults.getUI(javax.swing.JComponent)

paramString

protected String paramString()
Returns a string representation of this JPanel. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.

Overrides:
paramString in class JComponent
Returns:
a string representation of this JPanel.

getAccessibleContext

public AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this JPanel. For JPanels, the AccessibleContext takes the form of an AccessibleJPanel. A new AccessibleJPanel instance is created if necessary.

Specified by:
getAccessibleContext in interface Accessible
Overrides:
getAccessibleContext in class JComponent
Returns:
an AccessibleJPanel that serves as the AccessibleContext of this JPanel

Java™ Platform
Standard Ed. 6

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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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