Java™ Platform
Standard Ed. 6

javax.swing.plaf.basic
Class BasicScrollBarUI

java.lang.Object
  extended by javax.swing.plaf.ComponentUI
      extended by javax.swing.plaf.ScrollBarUI
          extended by 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


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.
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
           
protected  Dimension maximumThumbSize
           
protected  Dimension minimumThumbSize
           
protected  BasicScrollBarUI.ModelListener modelListener
           
protected static int NO_HIGHLIGHT
           
protected  PropertyChangeListener propertyChangeListener
           
protected  JScrollBar scrollbar
           
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
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()
           
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()
          Return the largest acceptable size for 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.
 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 appropriate 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 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)
           
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
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 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()

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 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), 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()
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

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

Java™ Platform
Standard Ed. 6

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