Class 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 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.

Fields

Modifier and Type Field Description
protected BasicScrollBarUI.ArrowButtonListener buttonListener

Button listener
protected JButton decrButton

Decrement button
protected static int DECREASE_HIGHLIGHT

Decrease highlight
protected int decrGap

Distance between the decrement button and the track.
protected JButton incrButton

Increment button
protected static 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 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

Constructors

Constructor Description
BasicScrollBarUI()

Methods

Modifier and Type Method Description
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.
protected void layoutHScrollbar​(JScrollBar sb)

Laysouts a vertical scroll bar.
protected void layoutVScrollbar​(JScrollBar sb)

Laysouts a vertical scroll bar.
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.
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

Methods declared in interface java.awt.LayoutManager

addLayoutComponent, layoutContainer, minimumLayoutSize, preferredLayoutSize, removeLayoutComponent

Fields

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

Constructors

BasicScrollBarUI

public BasicScrollBarUI()

Methods

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()

layoutVScrollbar

protected void layoutVScrollbar(JScrollBar sb)

Laysouts a vertical scroll bar.

Parameters:
sb - the scroll bar

layoutHScrollbar

protected void layoutHScrollbar(JScrollBar sb)

Laysouts a vertical scroll bar.

Parameters:
sb - the scroll bar

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:
LayoutManager.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

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https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/javax/swing/plaf/basic/BasicScrollBarUI.html