Module java.desktop

Package javax.swing

Class JScrollBar

java.lang.Object

java.awt.Component

java.awt.Container

javax.swing.JComponent

javax.swing.JScrollBar

All Implemented Interfaces:

Adjustable, ImageObserver, MenuContainer, Serializable, Accessible

Direct Known Subclasses:

JScrollPane.ScrollBar

@JavaBean(defaultProperty="UI",
          description="A component that helps determine the visible content range of an area.")
public class JScrollBar
extends JComponent
implements Adjustable, Accessible

An implementation of a scrollbar. The user positions the knob in the scrollbar to determine the contents of the viewing area. The program typically adjusts the display so that the end of the scrollbar represents the end of the displayable contents, or 100% of the contents. The start of the scrollbar is the beginning of the displayable contents, or 0%. The position of the knob within those bounds then translates to the corresponding percentage of the displayable contents.

Typically, as the position of the knob in the scrollbar changes a corresponding change is made to the position of the JViewport on the underlying view, changing the contents of the JViewport.

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

Since:

1.2

See Also:

• JScrollPane

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	JScrollBar.AccessibleJScrollBar	This class implements accessibility support for the JScrollBar class.

Nested classes/interfaces declared in class javax.swing.JComponent

JComponent.AccessibleJComponent

Nested classes/interfaces declared in class java.awt.Container

Container.AccessibleAWTContainer

Nested classes/interfaces declared in class java.awt.Component

Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy

Field Summary

Fields

Modifier and Type	Field	Description
protected int	blockIncrement
protected BoundedRangeModel	model	The model that represents the scrollbar's minimum, maximum, extent (aka "visibleAmount") and current value.
protected int	orientation
protected int	unitIncrement

Fields declared in class javax.swing.JComponent

listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW

Fields declared in class java.awt.Component

accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields declared in interface java.awt.Adjustable

HORIZONTAL, NO_ORIENTATION, VERTICAL

Fields declared in interface java.awt.image.ImageObserver

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

Constructor Summary

Constructors

Constructor	Description
JScrollBar()	Creates a vertical scrollbar with the following initial values:
JScrollBar(int orientation)	Creates a scrollbar with the specified orientation and the following initial values:
JScrollBar(int orientation, int value, int extent, int min, int max)	Creates a scrollbar with the specified orientation, value, extent, minimum, and maximum.

Method Summary

Modifier and Type	Method	Description
void	addAdjustmentListener(AdjustmentListener l)	Adds an AdjustmentListener.
protected void	fireAdjustmentValueChanged(int id, int type, int value)	Notify listeners that the scrollbar's model has changed.
AccessibleContext	getAccessibleContext()	Gets the AccessibleContext associated with this JScrollBar.
AdjustmentListener[]	getAdjustmentListeners()	Returns an array of all the AdjustmentListeners added to this JScrollBar with addAdjustmentListener().
int	getBlockIncrement()	For backwards compatibility with java.awt.Scrollbar.
int	getBlockIncrement(int direction)	Returns the amount to change the scrollbar's value by, given a block (usually "page") up/down request.
int	getMaximum()	The maximum value of the scrollbar is maximum - extent.
Dimension	getMaximumSize()	The scrollbar is flexible along it's scrolling axis and rigid along the other axis.
int	getMinimum()	Returns the minimum value supported by the scrollbar (usually zero).
Dimension	getMinimumSize()	The scrollbar is flexible along it's scrolling axis and rigid along the other axis.
BoundedRangeModel	getModel()	Returns data model that handles the scrollbar's four fundamental properties: minimum, maximum, value, extent.
int	getOrientation()	Returns the component's orientation (horizontal or vertical).
ScrollBarUI	getUI()	Returns the delegate that implements the look and feel for this component.
String	getUIClassID()	Returns the name of the LookAndFeel class for this component.
int	getUnitIncrement()	For backwards compatibility with java.awt.Scrollbar.
int	getUnitIncrement(int direction)	Returns the amount to change the scrollbar's value by, given a unit up/down request.
int	getValue()	Returns the scrollbar's value.
boolean	getValueIsAdjusting()	True if the scrollbar knob is being dragged.
int	getVisibleAmount()	Returns the scrollbar's extent, aka its "visibleAmount".
protected String	paramString()	Returns a string representation of this JScrollBar.
void	removeAdjustmentListener(AdjustmentListener l)	Removes an AdjustmentEvent listener.
void	setBlockIncrement(int blockIncrement)	Sets the blockIncrement property.
void	setEnabled(boolean x)	Enables the component so that the knob position can be changed.
void	setMaximum(int maximum)	Sets the model's maximum property.
void	setMinimum(int minimum)	Sets the model's minimum property.
void	setModel(BoundedRangeModel newModel)	Sets the model that handles the scrollbar's four fundamental properties: minimum, maximum, value, extent.
void	setOrientation(int orientation)	Set the scrollbar's orientation to either VERTICAL or HORIZONTAL.
void	setUI(ScrollBarUI ui)	Sets the L&F object that renders this component.
void	setUnitIncrement(int unitIncrement)	Sets the unitIncrement property.
void	setValue(int value)	Sets the scrollbar's value.
void	setValueIsAdjusting(boolean b)	Sets the model's valueIsAdjusting property.
void	setValues(int newValue, int newExtent, int newMin, int newMax)	Sets the four BoundedRangeModel properties after forcing the arguments to obey the usual constraints:
void	setVisibleAmount(int extent)	Set the model's extent property.
void	updateUI()	Overrides JComponent.updateUI.

Methods declared in class javax.swing.JComponent

addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, 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, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately,