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

public class BasicScrollBarUI

extends ScrollBarUI

implements LayoutManager, SwingConstants

Implementation of ScrollBarUI for the Basic Look and Feel

Author:

Rich Schiavi, David Kloba, Hans Muller

Nested Class Summary

protected class	BasicScrollBarUI.ArrowButtonListener Listener for cursor keys.
protected class	BasicScrollBarUI.ModelListener A listener to listen for model changes.
class	BasicScrollBarUI.PropertyChangeHandler
protected class	BasicScrollBarUI.ScrollListener Listener for scrolling events initiated in the ScrollPane.
private static class	BasicScrollBarUI.SharedActionScroller Used for scrolling the scrollbar.
protected class	BasicScrollBarUI.TrackListener Track mouse drags.

Field Summary

protected BasicScrollBarUI.ArrowButtonListener	buttonListener
protected JButton	decrButton
protected static int	DECREASE_HIGHLIGHT
protected JButton	incrButton
protected static int	INCREASE_HIGHLIGHT
protected boolean	isDragging
private static int	MAX_SCROLL
protected Dimension	maximumThumbSize
private static int	MIN_SCROLL
protected Dimension	minimumThumbSize
protected BasicScrollBarUI.ModelListener	modelListener
private static int	NEGATIVE_SCROLL
protected static int	NO_HIGHLIGHT
private static int	POSITIVE_SCROLL
protected java.beans.PropertyChangeListener	propertyChangeListener
protected JScrollBar	scrollbar
private int	scrollBarWidth Hint as to what width (when vertical) or height (when horizontal) should be.
protected BasicScrollBarUI.ScrollListener	scrollListener
private static int	scrollSpeedThrottle
protected Timer	scrollTimer
private boolean	supportsAbsolutePositioning True indicates a middle click will absolutely position the scrollbar.
protected Color	thumbColor
protected Color	thumbDarkShadowColor
protected Color	thumbHighlightColor
protected Color	thumbLightShadowColor
protected Rectangle	thumbRect
protected Color	trackColor
protected int	trackHighlight
protected Color	trackHighlightColor
protected BasicScrollBarUI.TrackListener	trackListener
protected Rectangle	trackRect

Fields inherited from 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

BasicScrollBarUI()

Method Summary

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()
private ActionMap	createActionMap()
protected BasicScrollBarUI.ArrowButtonListener	createArrowButtonListener()
protected JButton	createDecreaseButton(int orientation)
protected JButton	createIncreaseButton(int orientation)
protected BasicScrollBarUI.ModelListener	createModelListener()
protected java.beans.PropertyChangeListener	createPropertyChangeListener()
protected BasicScrollBarUI.ScrollListener	createScrollListener()
protected BasicScrollBarUI.TrackListener	createTrackListener()
static ComponentUI	createUI(JComponent c) Returns an instance of the UI delegate for the specified component.
private ActionMap	getActionMap()
private InputMap	getInputMap(int condition)
Dimension	getMaximumSize(JComponent c) Returns the specified component's maximum size appropriate for the look and feel.
protected Dimension	getMaximumThumbSize() Return the largest acceptable size for the thumb.
Dimension	getMinimumSize(JComponent c) A vertical scrollbar's minimum width is the largest minimum width of the (non null) increment/decrement buttons, and the minimum width of the thumb.
protected Dimension	getMinimumThumbSize() Return 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.
private boolean	getSupportsAbsolutePositioning() Indicates whether the user can absolutely position the offset with a mouse click (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()
protected void	installDefaults()
protected void	installKeyboardActions()
protected void	installListeners()
void	installUI(JComponent c) Configures the specified component appropriate for the look and feel.
void	layoutContainer(Container scrollbarContainer) Lays out the specified container.
protected void	layoutHScrollbar(JScrollBar sb)
protected void	layoutVScrollbar(JScrollBar sb)
Dimension	minimumLayoutSize(Container scrollbarContainer) Calculates the minimum size dimensions for the specified container, given the components it contains.
void	paint(Graphics g, JComponent c) Paints the specified component appropriate for the look and feel.
protected void	paintDecreaseHighlight(Graphics g)
protected void	paintIncreaseHighlight(Graphics g)
protected void	paintThumb(Graphics g, JComponent c, Rectangle thumbBounds)
protected void	paintTrack(Graphics g, JComponent c, Rectangle trackBounds)
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)
(package private) static void	scrollByBlock(JScrollBar scrollbar, int direction)
protected void	scrollByUnit(int direction)
(package private) static void	scrollByUnits(JScrollBar scrollbar, int direction, int units)
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	uninstallComponents()
protected void	uninstallDefaults()
protected void	uninstallKeyboardActions()
protected void	uninstallListeners()
void	uninstallUI(JComponent c) Reverses configuration which was done on the specified component during installUI.

Methods inherited from class javax.swing.plaf.ComponentUI

contains, getAccessibleChild, getAccessibleChildrenCount, update

Methods inherited from class java.lang.Object

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

Field Detail

POSITIVE_SCROLL

private static final int POSITIVE_SCROLL

See Also:

Constant Field Values

NEGATIVE_SCROLL

private static final int NEGATIVE_SCROLL

See Also:

Constant Field Values

MIN_SCROLL

private static final int MIN_SCROLL

See Also:

Constant Field Values

MAX_SCROLL

private static final int MAX_SCROLL

See Also:

Constant Field Values

minimumThumbSize

protected Dimension minimumThumbSize

maximumThumbSize

protected Dimension maximumThumbSize

thumbHighlightColor

protected Color thumbHighlightColor

thumbLightShadowColor

protected Color thumbLightShadowColor

thumbDarkShadowColor

protected Color thumbDarkShadowColor

thumbColor

protected Color thumbColor

trackColor

protected Color trackColor

trackHighlightColor

protected Color trackHighlightColor

scrollbar

protected JScrollBar scrollbar

incrButton

protected JButton incrButton

decrButton

protected JButton decrButton

isDragging

protected boolean isDragging

trackListener

protected BasicScrollBarUI.TrackListener trackListener

buttonListener

protected BasicScrollBarUI.ArrowButtonListener buttonListener

modelListener

protected BasicScrollBarUI.ModelListener modelListener

thumbRect

protected Rectangle thumbRect

trackRect

protected Rectangle trackRect

trackHighlight

protected int trackHighlight

NO_HIGHLIGHT

protected static final int NO_HIGHLIGHT

See Also:

Constant Field Values

DECREASE_HIGHLIGHT

protected static final int DECREASE_HIGHLIGHT

See Also:

Constant Field Values

INCREASE_HIGHLIGHT

protected static final int INCREASE_HIGHLIGHT

See Also:

Constant Field Values

scrollListener

protected BasicScrollBarUI.ScrollListener scrollListener

propertyChangeListener

protected java.beans.PropertyChangeListener propertyChangeListener

scrollTimer

protected Timer scrollTimer

scrollSpeedThrottle

private static final int scrollSpeedThrottle

See Also:

Constant Field Values

supportsAbsolutePositioning

private boolean supportsAbsolutePositioning

True indicates a middle click will absolutely position the scrollbar.

scrollBarWidth

private int scrollBarWidth

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

Constructor Detail

BasicScrollBarUI

public BasicScrollBarUI()

Method Detail

createUI

public static ComponentUI createUI(JComponent c)

Description copied from class: ComponentUI

Returns an instance of the UI delegate for the specified component. Each subclass must provide its own static createUI method that returns an instance of that UI delegate subclass. If the UI delegate subclass is stateless, it may return an instance that is shared by multiple components. If the UI delegate is stateful, then it should return a new instance per component. The default implementation of this method throws an error, as it should never be invoked.

configureScrollBarColors

protected void configureScrollBarColors()

installUI

public void installUI(JComponent c)

Description copied from class: ComponentUI

Configures the specified component appropriate for the look and feel. This method is invoked when the ComponentUI instance is being installed as the UI delegate on the specified component. This method should completely configure the component for the look and feel, including the following:

1. Install any default property values for color, fonts, borders, icons, opacity, etc. on the component. Whenever possible, property values initialized by the client program should not be overridden.
2. Install a LayoutManager on the component if necessary.
3. Create/add any required sub-components to the component.
4. Create/install event listeners on the component.
5. Create/install a PropertyChangeListener on the component in order to detect and respond to component property changes appropriately.
6. Install keyboard UI (mnemonics, traversal, etc.) on the component.
7. Initialize any appropriate instance data.

Overrides:

installUI in class ComponentUI

Parameters:

c - the component where this UI delegate is being installed

See Also:

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

uninstallUI

public void uninstallUI(JComponent c)

Description copied from class: ComponentUI

Reverses configuration which was done on the specified component during installUI. This method is invoked when this UIComponent instance is being removed as the UI delegate for the specified component. This method should undo the configuration performed in installUI, being careful to leave the JComponent instance in a clean state (no extraneous listeners, look-and-feel-specific property objects, etc.). This should include the following:

1. Remove any UI-set borders from the component.
2. Remove any UI-set layout managers on the component.
3. Remove any UI-added sub-components from the component.
4. Remove any UI-added event/property listeners from the component.
5. Remove any UI-installed keyboard UI from the component.
6. Nullify any allocated instance data objects to allow for GC.

Overrides:

uninstallUI in class ComponentUI

Parameters:

c - the component from which this UI delegate is being removed; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components

See Also:

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

installDefaults

protected void installDefaults()

installComponents

protected void installComponents()

uninstallComponents

protected void uninstallComponents()

installListeners

protected void installListeners()

installKeyboardActions

protected void installKeyboardActions()

uninstallKeyboardActions

protected void uninstallKeyboardActions()

getInputMap

private InputMap getInputMap(int condition)

getActionMap

private ActionMap getActionMap()

createActionMap

private ActionMap createActionMap()

uninstallListeners

protected void uninstallListeners()

uninstallDefaults

protected void uninstallDefaults()

createTrackListener

protected BasicScrollBarUI.TrackListener createTrackListener()

createArrowButtonListener

protected BasicScrollBarUI.ArrowButtonListener createArrowButtonListener()

createModelListener

protected BasicScrollBarUI.ModelListener createModelListener()

createScrollListener

protected BasicScrollBarUI.ScrollListener createScrollListener()

createPropertyChangeListener

protected java.beans.PropertyChangeListener createPropertyChangeListener()

paint

public void paint(Graphics g,
                  JComponent c)

Description copied from class: ComponentUI

Paints the specified component appropriate for the look and feel. This method is invoked from the ComponentUI.update method when the specified component is being painted. Subclasses should override this method and use the specified Graphics object to render the content of the component.

Overrides:

paint in class ComponentUI

Parameters:

g - the Graphics context in which to paint

c - the component being painted; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components

See Also:

ComponentUI.update(java.awt.Graphics, javax.swing.JComponent)

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), getMinimumSize(javax.swing.JComponent)

getMinimumSize

public Dimension getMinimumSize(JComponent c)

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

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

Overrides:

getMinimumSize in class ComponentUI

Parameters:

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

Returns:

the minimum size of a basic JScrollBar

See Also:

getMaximumSize(javax.swing.JComponent), getPreferredSize(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:

getMinimumSize(javax.swing.JComponent), getPreferredSize(javax.swing.JComponent)

createDecreaseButton

protected JButton createDecreaseButton(int orientation)

createIncreaseButton

protected JButton createIncreaseButton(int orientation)

paintDecreaseHighlight

protected void paintDecreaseHighlight(Graphics g)

paintIncreaseHighlight

protected void paintIncreaseHighlight(Graphics g)

paintTrack

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

paintThumb

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

getMinimumThumbSize

protected Dimension getMinimumThumbSize()

Return 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()

Return 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

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

See Also:

LayoutManager.preferredLayoutSize(java.awt.Container)

layoutVScrollbar

protected void layoutVScrollbar(JScrollBar sb)

layoutHScrollbar

protected void layoutHScrollbar(JScrollBar sb)

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.

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

static void scrollByBlock(JScrollBar scrollbar,
                          int direction)

scrollByBlock

protected void scrollByBlock(int direction)

scrollByUnits

static void scrollByUnits(JScrollBar scrollbar,
                          int direction,
                          int units)

scrollByUnit

protected void scrollByUnit(int direction)

getSupportsAbsolutePositioning

private boolean getSupportsAbsolutePositioning()

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

The return value is determined from the UIManager property ScrollBar.allowsAbsolutePositioning.