BasicScrollBarUI (Java Platform SE 8 )

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 and Description
`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`.
`protected class`	`BasicScrollBarUI.TrackListener` Track mouse drags.

Field Summary

Fields
Modifier and Type	Field and Description
`protected BasicScrollBarUI.ArrowButtonListener`	`buttonListener`
`protected JButton`	`decrButton`
`protected static int`	`DECREASE_HIGHLIGHT`
`protected int`	`decrGap` Distance between the decrement button and the track.
`protected JButton`	`incrButton`
`protected static int`	`INCREASE_HIGHLIGHT`
`protected int`	`incrGap` Distance between the increment button and the track.
`protected boolean`	`isDragging`
`protected Dimension`	`maximumThumbSize`
`protected Dimension`	`minimumThumbSize`
`protected BasicScrollBarUI.ModelListener`	`modelListener`
`protected static int`	`NO_HIGHLIGHT`
`protected PropertyChangeListener`	`propertyChangeListener`
`protected JScrollBar`	`scrollbar`
`protected int`	`scrollBarWidth` Hint as to what width (when vertical) or height (when horizontal) should be.
`protected BasicScrollBarUI.ScrollListener`	`scrollListener`
`protected Timer`	`scrollTimer`
`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

Constructors
Constructor and Description

BasicScrollBarUI()

Constructors
Constructor and Description
`BasicScrollBarUI()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and 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()`
`protected BasicScrollBarUI.ArrowButtonListener`	`createArrowButtonListener()`
`protected JButton`	`createDecreaseButton(int orientation)`
`protected JButton`	`createIncreaseButton(int orientation)`
`protected BasicScrollBarUI.ModelListener`	`createModelListener()`
`protected PropertyChangeListener`	`createPropertyChangeListener()`
`protected BasicScrollBarUI.ScrollListener`	`createScrollListener()`
`protected BasicScrollBarUI.TrackListener`	`createTrackListener()`
`static ComponentUI`	`createUI(JComponent c)`
`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.
`protected void`	`installComponents()`
`protected void`	`installDefaults()`
`protected void`	`installKeyboardActions()`
`protected void`	`installListeners()`
`void`	`installUI(JComponent c)` Configures the specified component appropriately for the look and feel.
`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)`
`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 appropriately 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)`
`protected void`	`scrollByUnit(int direction)`
`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()`
`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, getBaseline, getBaselineResizeBehavior, getMinimumSize, update

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - 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 PropertyChangeListener propertyChangeListener
```
  - scrollTimer
```
protected Timer scrollTimer
```
  - 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 Detail
  - BasicScrollBarUI
```
public BasicScrollBarUI()
```
- Method Detail
  - createUI
```
public static ComponentUI createUI(JComponent c)
```
  - configureScrollBarColors
```
protected void configureScrollBarColors()
```
  - installUI
```
public void installUI(JComponent c)
```
    Description copied from class: ComponentUI
    Configures the specified component appropriately 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 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()
```
  - 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 PropertyChangeListener createPropertyChangeListener()
```
  - 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
  - paint
```
public void paint(Graphics g,
                  JComponent c)
```
    Description copied from class: ComponentUI
    
    Paints the specified component appropriately 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), 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)
```
  - 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()
```
    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
    
    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
```
protected void scrollByBlock(int direction)
```
  - scrollByUnit
```
protected void scrollByUnit(int direction)
```
  - 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

Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2016, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.

Class BasicScrollBarUI

Nested Class Summary

Field Summary

Fields inherited from interface javax.swing.SwingConstants

Constructor Summary

Method Summary

Methods inherited from class javax.swing.plaf.ComponentUI

Methods inherited from class java.lang.Object

Field Detail

minimumThumbSize

maximumThumbSize

thumbHighlightColor

thumbLightShadowColor

thumbDarkShadowColor

thumbColor

trackColor

trackHighlightColor

scrollbar

incrButton

decrButton

isDragging

trackListener

buttonListener

modelListener

thumbRect

trackRect

trackHighlight

NO_HIGHLIGHT

DECREASE_HIGHLIGHT

INCREASE_HIGHLIGHT

scrollListener

propertyChangeListener

scrollTimer

scrollBarWidth

incrGap

decrGap

Constructor Detail

BasicScrollBarUI

Method Detail

createUI

configureScrollBarColors

installUI

uninstallUI

installDefaults

installComponents

uninstallComponents

installListeners

installKeyboardActions

uninstallKeyboardActions

uninstallListeners

uninstallDefaults

createTrackListener

createArrowButtonListener

createModelListener

createScrollListener

createPropertyChangeListener

setThumbRollover

isThumbRollover

paint

getPreferredSize

getMaximumSize

createDecreaseButton

createIncreaseButton

paintDecreaseHighlight

paintIncreaseHighlight

paintTrack

paintThumb

getMinimumThumbSize

getMaximumThumbSize

addLayoutComponent

removeLayoutComponent

preferredLayoutSize

minimumLayoutSize

layoutVScrollbar

layoutHScrollbar

layoutContainer

setThumbBounds

getThumbBounds

getTrackBounds

scrollByBlock