Module java.desktop

Package javax.swing.plaf.basic

Class BasicScrollBarUI

java.lang.Object

javax.swing.plaf.ComponentUI

javax.swing.plaf.ScrollBarUI

javax.swing.plaf.basic.BasicScrollBarUI

All Implemented Interfaces:

LayoutManager, SwingConstants

Direct Known Subclasses:

MetalScrollBarUI, SynthScrollBarUI

public class BasicScrollBarUI
extends ScrollBarUI
implements LayoutManager, SwingConstants

Implementation of ScrollBarUI for the Basic Look and Feel

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	BasicScrollBarUI.ArrowButtonListener	Listener for cursor keys.
protected class	BasicScrollBarUI.ModelListener	A listener to listen for model changes.
class	BasicScrollBarUI.PropertyChangeHandler	Property change handler
protected class	BasicScrollBarUI.ScrollListener	Listener for scrolling events initiated in the ScrollPane.
protected class	BasicScrollBarUI.TrackListener	Track mouse drags.

Field Summary

Fields

Modifier and Type	Field	Description
protected BasicScrollBarUI.ArrowButtonListener	buttonListener	Button listener
protected JButton	decrButton	Decrement button
protected static final int	DECREASE_HIGHLIGHT	Decrease highlight
protected int	decrGap	Distance between the decrement button and the track.
protected JButton	incrButton	Increment button
protected static final int	INCREASE_HIGHLIGHT	Increase highlight
protected int	incrGap	Distance between the increment button and the track.
protected boolean	isDragging	Dragging
protected Dimension	maximumThumbSize	Maximum thumb size
protected Dimension	minimumThumbSize	Minimum thumb size
protected BasicScrollBarUI.ModelListener	modelListener	Model listener
protected static final int	NO_HIGHLIGHT	No highlight
protected PropertyChangeListener	propertyChangeListener	Property change listener
protected JScrollBar	scrollbar	Scrollbar
protected int	scrollBarWidth	Hint as to what width (when vertical) or height (when horizontal) should be.
protected BasicScrollBarUI.ScrollListener	scrollListener	Scroll listener
protected Timer	scrollTimer	Scroll timer
protected Color	thumbColor	Thumb color
protected Color	thumbDarkShadowColor	Thumb dark shadow color
protected Color	thumbHighlightColor	Thumb highlight color
protected Color	thumbLightShadowColor	Thumb light shadow color
protected Rectangle	thumbRect	Thumb rectangle
protected Color	trackColor	Track color
protected int	trackHighlight	Track highlight
protected Color	trackHighlightColor	Track highlight color
protected BasicScrollBarUI.TrackListener	trackListener	Track listener
protected Rectangle	trackRect	Track rectangle

Fields declared in interface javax.swing.SwingConstants

BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST

Constructor Summary

Constructors

Constructor	Description
BasicScrollBarUI()	Constructs a BasicScrollBarUI.

Method Summary

Modifier and Type	Method	Description
void	addLayoutComponent(String name, Component child)	If the layout manager uses a per-component string, adds the component comp to the layout, associating it with the string specified by name.
protected void	configureScrollBarColors()	Configures the scroll bar colors.
protected BasicScrollBarUI.ArrowButtonListener	createArrowButtonListener()	Creates an arrow button listener.
protected JButton	createDecreaseButton(int orientation)	Creates a decrease button.
protected JButton	createIncreaseButton(int orientation)	Creates an increase button.
protected BasicScrollBarUI.ModelListener	createModelListener()	Creates a model listener.
protected PropertyChangeListener	createPropertyChangeListener()	Creates a property change listener.
protected BasicScrollBarUI.ScrollListener	createScrollListener()	Creates a scroll listener.
protected BasicScrollBarUI.TrackListener	createTrackListener()	Creates a track listener.
static ComponentUI	createUI(JComponent c)	Creates the UI.
Dimension	getMaximumSize(JComponent c)	Returns the specified component's maximum size appropriate for the look and feel.
protected Dimension	getMaximumThumbSize()	Returns the largest acceptable size for the thumb.
protected Dimension	getMinimumThumbSize()	Returns the smallest acceptable size for the thumb.
Dimension	getPreferredSize(JComponent c)	A vertical scrollbar's preferred width is the maximum of preferred widths of the (non null) increment/decrement buttons, and the minimum width of the thumb.
boolean	getSupportsAbsolutePositioning()	Indicates whether the user can absolutely position the thumb with a mouse gesture (usually the middle mouse button).
protected Rectangle	getThumbBounds()	Return the current size/location of the thumb.
protected Rectangle	getTrackBounds()	Returns the current bounds of the track, i.e. the space in between the increment and decrement buttons, less the insets.
protected void	installComponents()	Installs the components.
protected void	installDefaults()	Installs the defaults.
protected void	installKeyboardActions()	Installs the keyboard actions.
protected void	installListeners()	Installs the listeners.
void	installUI(JComponent c)	Installs the UI.
boolean	isThumbRollover()	Returns true if the mouse is currently over the thumb.
void	layoutContainer(Container scrollbarContainer)	Lays out the specified container.
protected void	layoutHScrollbar(JScrollBar sb)	Lays out a horizontal scroll bar.
protected void	layoutVScrollbar(JScrollBar sb)	Lays out a vertical scroll bar.
Dimension	minimumLayoutSize(Container scrollbarContainer)	Calculates the minimum size dimensions for the specified container, given the components it contains.
protected void	paintDecreaseHighlight(Graphics g)	Paints the decrease highlight.
protected void	paintIncreaseHighlight(Graphics g)	Paints the increase highlight.
protected void	paintThumb(Graphics g, JComponent c, Rectangle thumbBounds)	Paints the thumb.
protected void	paintTrack(Graphics g, JComponent c, Rectangle trackBounds)	Paints the track.
Dimension	preferredLayoutSize(Container scrollbarContainer)	Calculates the preferred size dimensions for the specified container, given the components it contains.
void	removeLayoutComponent(Component child)	Removes the specified component from the layout.
protected void	scrollByBlock(int direction)	Scrolls by block.
protected void	scrollByUnit(int direction)	Scrolls by unit.
protected void	setThumbBounds(int x, int y, int width, int height)	Set the bounds of the thumb and force a repaint that includes the old thumbBounds and the new one.
protected void	setThumbRollover(boolean active)	Sets whether or not the mouse is currently over the thumb.
protected void	uninstallComponents()	Uninstalls the components.
protected void	uninstallDefaults()	Uninstalls the defaults.
protected void	uninstallKeyboardActions()	Uninstalls the keyboard actions.
protected void	uninstallListeners()	Uninstall the listeners.
void	uninstallUI(JComponent c)	Uninstalls the UI.

Methods declared in class javax.swing.plaf.ComponentUI

contains, getAccessibleChild, getAccessibleChildrenCount, getBaseline, getBaselineResizeBehavior, getMinimumSize, paint, update

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

minimumThumbSize

protected Dimension minimumThumbSize

Minimum thumb size

maximumThumbSize

protected Dimension maximumThumbSize

Maximum thumb size

thumbHighlightColor

protected Color thumbHighlightColor

Thumb highlight color

thumbLightShadowColor

protected Color thumbLightShadowColor

Thumb light shadow color

thumbDarkShadowColor

protected Color thumbDarkShadowColor

Thumb dark shadow color

thumbColor

protected Color thumbColor

Thumb color

trackColor

protected Color trackColor

Track color

trackHighlightColor

protected Color trackHighlightColor

Track highlight color

scrollbar

protected JScrollBar scrollbar

Scrollbar

incrButton

protected JButton incrButton

Increment button

decrButton

protected JButton decrButton

Decrement button

isDragging

protected boolean isDragging

Dragging

trackListener

protected BasicScrollBarUI.TrackListener trackListener

Track listener

buttonListener

protected BasicScrollBarUI.ArrowButtonListener buttonListener

Button listener

modelListener

protected BasicScrollBarUI.ModelListener modelListener

Model listener

thumbRect

protected Rectangle thumbRect

Thumb rectangle

trackRect

protected Rectangle trackRect

Track rectangle

trackHighlight

protected int trackHighlight

Track highlight

NO_HIGHLIGHT

protected static final int NO_HIGHLIGHT

No highlight

See Also:

• Constant Field Values

DECREASE_HIGHLIGHT

protected static final int DECREASE_HIGHLIGHT

Decrease highlight

See Also:

• Constant Field Values

INCREASE_HIGHLIGHT

protected static final int INCREASE_HIGHLIGHT

Increase highlight

See Also:

• Constant Field Values

scrollListener

protected BasicScrollBarUI.ScrollListener scrollListener

Scroll listener

propertyChangeListener

protected PropertyChangeListener propertyChangeListener

Property change listener

scrollTimer

protected Timer scrollTimer

Scroll timer

scrollBarWidth

protected int scrollBarWidth

Hint as to what width (when vertical) or height (when horizontal) should be.

Since:

1.7

incrGap

protected int incrGap

Distance between the increment button and the track. This may be a negative number. If negative, then an overlap between the button and track will occur, which is useful for shaped buttons.

Since:

1.7

decrGap

protected int decrGap

Distance between the decrement button and the track. This may be a negative number. If negative, then an overlap between the button and track will occur, which is useful for shaped buttons.

Since:

1.7

Constructor Details

BasicScrollBarUI

public BasicScrollBarUI()

Constructs a BasicScrollBarUI.

Method Details

createUI

public static ComponentUI createUI(JComponent c)

Creates the UI.

Parameters:

c - the component

Returns:

the UI

configureScrollBarColors

protected void configureScrollBarColors()

Configures the scroll bar colors.

installUI

public void installUI(JComponent c)

Installs the UI.

Overrides:

installUI in class ComponentUI

Parameters:

c - the component

See Also:

• ComponentUI.uninstallUI(javax.swing.JComponent)
• JComponent.setUI(javax.swing.plaf.ComponentUI)
• JComponent.updateUI()

uninstallUI

public void uninstallUI(JComponent c)

Uninstalls the UI.

Overrides:

uninstallUI in class ComponentUI

Parameters:

c - the component

See Also:

• ComponentUI.installUI(javax.swing.JComponent)
• JComponent.updateUI()

installDefaults

protected void installDefaults()

Installs the defaults.

installComponents

protected void installComponents()

Installs the components.

uninstallComponents

protected void uninstallComponents()

Uninstalls the components.

installListeners

protected void installListeners()

Installs the listeners.

installKeyboardActions

protected void installKeyboardActions()

Installs the keyboard actions.

uninstallKeyboardActions

protected void uninstallKeyboardActions()

Uninstalls the keyboard actions.

uninstallListeners

protected void uninstallListeners()

Uninstall the listeners.

uninstallDefaults

protected void uninstallDefaults()

Uninstalls the defaults.

createTrackListener

protected BasicScrollBarUI.TrackListener createTrackListener()

Creates a track listener.

Returns:

a track listener

createArrowButtonListener

protected BasicScrollBarUI.ArrowButtonListener createArrowButtonListener()

Creates an arrow button listener.

Returns:

an arrow button listener

createModelListener

protected BasicScrollBarUI.ModelListener createModelListener()

Creates a model listener.

Returns:

a model listener

createScrollListener

protected BasicScrollBarUI.ScrollListener createScrollListener()

Creates a scroll listener.

Returns:

a scroll listener

createPropertyChangeListener

protected PropertyChangeListener createPropertyChangeListener()

Creates a property change listener.

Returns:

a property change listener

setThumbRollover

protected void setThumbRollover(boolean active)

Sets whether or not the mouse is currently over the thumb.

Parameters:

active - True indicates the thumb is currently active.

Since:

1.5

isThumbRollover

public boolean isThumbRollover()

Returns true if the mouse is currently over the thumb.

Returns:

true if the thumb is currently active

Since:

1.5

getPreferredSize

public Dimension getPreferredSize(JComponent c)

A vertical scrollbar's preferred width is the maximum of preferred widths of the (non null) increment/decrement buttons, and the minimum width of the thumb. The preferred height is the sum of the preferred heights of the same parts. The basis for the preferred size of a horizontal scrollbar is similar.

The preferredSize is only computed once, subsequent calls to this method just return a cached size.

Overrides:

getPreferredSize in class ComponentUI

Parameters:

c - the JScrollBar that's delegating this method to us

Returns:

the preferred size of a Basic JScrollBar

See Also:

• getMaximumSize(javax.swing.JComponent)
• ComponentUI.getMinimumSize(javax.swing.JComponent)

getMaximumSize

public Dimension getMaximumSize(JComponent c)

Description copied from class: ComponentUI

Returns the specified component's maximum size appropriate for the look and feel. If null is returned, the maximum size will be calculated by the component's layout manager instead (this is the preferred approach for any component with a specific layout manager installed). The default implementation of this method invokes getPreferredSize and returns that value.

Overrides:

getMaximumSize in class ComponentUI

Parameters:

c - The JScrollBar that's delegating this method to us.

Returns:

new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);

See Also:

• ComponentUI.getMinimumSize(javax.swing.JComponent)
• getPreferredSize(javax.swing.JComponent)

createDecreaseButton

protected JButton createDecreaseButton(int orientation)

Creates a decrease button.

Parameters:

orientation - the orientation

Returns:

a decrease button

createIncreaseButton

protected JButton createIncreaseButton(int orientation)

Creates an increase button.

Parameters:

orientation - the orientation

Returns:

an increase button

paintDecreaseHighlight

protected void paintDecreaseHighlight(Graphics g)

Paints the decrease highlight.

Parameters:

g - the graphics

paintIncreaseHighlight

protected void paintIncreaseHighlight(Graphics g)

Paints the increase highlight.

Parameters:

g - the graphics

paintTrack

protected void paintTrack(Graphics g,
 JComponent c,
 Rectangle trackBounds)

Paints the track.

Parameters:

g - the graphics

c - the component

trackBounds - the track bounds

paintThumb

protected void paintThumb(Graphics g,
 JComponent c,
 Rectangle thumbBounds)

Paints the thumb.

Parameters:

g - the graphics

c - the component

thumbBounds - the thumb bounds

getMinimumThumbSize

protected Dimension getMinimumThumbSize()

Returns the smallest acceptable size for the thumb. If the scrollbar becomes so small that this size isn't available, the thumb will be hidden.

Warning : the value returned by this method should not be be modified, it's a shared static constant.

Returns:

The smallest acceptable size for the thumb.

See Also:

• getMaximumThumbSize()

getMaximumThumbSize

protected Dimension getMaximumThumbSize()

Returns the largest acceptable size for the thumb. To create a fixed size thumb one make this method and getMinimumThumbSize return the same value.

Warning : the value returned by this method should not be be modified, it's a shared static constant.

Returns:

The largest acceptable size for the thumb.

See Also:

• getMinimumThumbSize()

addLayoutComponent

public void addLayoutComponent(String name,
 Component child)

Description copied from interface: LayoutManager

If the layout manager uses a per-component string, adds the component comp to the layout, associating it with the string specified by name.

Specified by:

addLayoutComponent in interface LayoutManager

Parameters:

name - the string to be associated with the component

child - the component to be added

removeLayoutComponent

public void removeLayoutComponent(Component child)

Description copied from interface: LayoutManager

Removes the specified component from the layout.

Specified by:

removeLayoutComponent in interface LayoutManager

Parameters:

child - the component to be removed

preferredLayoutSize

public Dimension preferredLayoutSize(Container scrollbarContainer)

Description copied from interface: LayoutManager

Calculates the preferred size dimensions for the specified container, given the components it contains.

Specified by:

preferredLayoutSize in interface LayoutManager

Parameters:

scrollbarContainer - the container to be laid out

Returns:

the preferred dimension for the container

See Also:

• LayoutManager.minimumLayoutSize(java.awt.Container)

minimumLayoutSize

public Dimension minimumLayoutSize(Container scrollbarContainer)

Description copied from interface: LayoutManager

Calculates the minimum size dimensions for the specified container, given the components it contains.

Specified by:

minimumLayoutSize in interface LayoutManager

Parameters:

scrollbarContainer - the component to be laid out

Returns:

the minimum dimension for the container

See Also:

• LayoutManager.preferredLayoutSize(java.awt.Container)

layoutVScrollbar

protected void layoutVScrollbar(JScrollBar sb)

Lays out a vertical scroll bar.

Parameters:

sb - the scroll bar

layoutHScrollbar

protected void layoutHScrollbar(JScrollBar sb)

Lays out a horizontal scroll bar.

Parameters:

sb - the scroll bar

layoutContainer

public void layoutContainer(Container scrollbarContainer)

Description copied from interface: LayoutManager

Lays out the specified container.

Specified by:

layoutContainer in interface LayoutManager

Parameters:

scrollbarContainer - the container to be laid out

setThumbBounds

protected void setThumbBounds(int x,
 int y,
 int width,
 int height)

Set the bounds of the thumb and force a repaint that includes the old thumbBounds and the new one.

Parameters:

x - set the x location of the thumb

y - set the y location of the thumb

width - set the width of the thumb

height - set the height of the thumb

See Also:

• getThumbBounds()

getThumbBounds

protected Rectangle getThumbBounds()

Return the current size/location of the thumb.

Warning : the value returned by this method should not be be modified, it's a reference to the actual rectangle, not a copy.

Returns:

The current size/location of the thumb.

See Also:

• setThumbBounds(int, int, int, int)

getTrackBounds

protected Rectangle getTrackBounds()

Returns the current bounds of the track, i.e. the space in between the increment and decrement buttons, less the insets. The value returned by this method is updated each time the scrollbar is laid out (validated).

Warning : the value returned by this method should not be be modified, it's a reference to the actual rectangle, not a copy.

Returns:

the current bounds of the scrollbar track

See Also:

• layoutContainer(java.awt.Container)

scrollByBlock

protected void scrollByBlock(int direction)

Scrolls by block.

Parameters:

direction - the direction to scroll

scrollByUnit

protected void scrollByUnit(int direction)

Scrolls by unit.

Parameters:

direction - the direction to scroll

getSupportsAbsolutePositioning

public boolean getSupportsAbsolutePositioning()

Indicates whether the user can absolutely position the thumb with a mouse gesture (usually the middle mouse button).

Returns:

true if a mouse gesture can absolutely position the thumb

Since:

1.5