JavaTM 2 Platform
Std. Ed. v1.4.2

javax.swing.plaf.basic
Class BasicScrollPaneUI

java.lang.Object
  extended byjavax.swing.plaf.ComponentUI
      extended byjavax.swing.plaf.ScrollPaneUI
          extended byjavax.swing.plaf.basic.BasicScrollPaneUI
All Implemented Interfaces:
ScrollPaneConstants
Direct Known Subclasses:
MetalScrollPaneUI

public class BasicScrollPaneUI
extends ScrollPaneUI
implements ScrollPaneConstants

A default L&F implementation of ScrollPaneUI.


Nested Class Summary
 class BasicScrollPaneUI.HSBChangeListener
          Horizontal scrollbar listener.
protected  class BasicScrollPaneUI.MouseWheelHandler
          MouseWheelHandler is an inner class which implements the MouseWheelListener interface.
 class BasicScrollPaneUI.PropertyChangeHandler
           
 class BasicScrollPaneUI.ViewportChangeHandler
          Listener for viewport events.
 class BasicScrollPaneUI.VSBChangeListener
          Vertical scrollbar listener.
 
Field Summary
protected  ChangeListener hsbChangeListener
           
protected  JScrollPane scrollpane
           
protected  PropertyChangeListener spPropertyChangeListener
           
protected  ChangeListener viewportChangeListener
           
protected  ChangeListener vsbChangeListener
           
 
Fields inherited from interface javax.swing.ScrollPaneConstants
COLUMN_HEADER, HORIZONTAL_SCROLLBAR, HORIZONTAL_SCROLLBAR_ALWAYS, HORIZONTAL_SCROLLBAR_AS_NEEDED, HORIZONTAL_SCROLLBAR_NEVER, HORIZONTAL_SCROLLBAR_POLICY, LOWER_LEADING_CORNER, LOWER_LEFT_CORNER, LOWER_RIGHT_CORNER, LOWER_TRAILING_CORNER, ROW_HEADER, UPPER_LEADING_CORNER, UPPER_LEFT_CORNER, UPPER_RIGHT_CORNER, UPPER_TRAILING_CORNER, VERTICAL_SCROLLBAR, VERTICAL_SCROLLBAR_ALWAYS, VERTICAL_SCROLLBAR_AS_NEEDED, VERTICAL_SCROLLBAR_NEVER, VERTICAL_SCROLLBAR_POLICY, VIEWPORT
 
Constructor Summary
BasicScrollPaneUI()
           
 
Method Summary
protected  ChangeListener createHSBChangeListener()
           
protected  MouseWheelListener createMouseWheelListener()
          Creates an instance of MouseWheelListener, which is added to the JScrollPane by installUI().
protected  PropertyChangeListener createPropertyChangeListener()
          Creates an instance of PropertyChangeListener that's added to the JScrollPane by installUI().
static ComponentUI createUI(JComponent x)
          Returns an instance of the UI delegate for the specified component.
protected  ChangeListener createViewportChangeListener()
           
protected  ChangeListener createVSBChangeListener()
           
 Dimension getMaximumSize(JComponent c)
          Returns the specified component's maximum size appropriate for the look and feel.
 Dimension getMinimumSize(JComponent c)
          Returns the specified component's minimum size appropriate for the look and feel.
 Dimension getPreferredSize(JComponent c)
          Returns the specified component's preferred size appropriate for the look and feel.
protected  void installDefaults(JScrollPane scrollpane)
           
protected  void installKeyboardActions(JScrollPane c)
           
protected  void installListeners(JScrollPane c)
           
 void installUI(JComponent x)
          Configures the specified component appropriate for the look and feel.
 void paint(Graphics g, JComponent c)
          Paints the specified component appropriate for the look and feel.
protected  void syncScrollPaneWithViewport()
           
protected  void uninstallDefaults(JScrollPane c)
           
protected  void uninstallKeyboardActions(JScrollPane c)
           
protected  void uninstallListeners(JComponent c)
           
 void uninstallUI(JComponent c)
          Reverses configuration which was done on the specified component during installUI.
protected  void updateColumnHeader(PropertyChangeEvent e)
           
protected  void updateRowHeader(PropertyChangeEvent e)
           
protected  void updateScrollBarDisplayPolicy(PropertyChangeEvent e)
           
protected  void updateViewport(PropertyChangeEvent e)
           
 
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

scrollpane

protected JScrollPane scrollpane

vsbChangeListener

protected ChangeListener vsbChangeListener

hsbChangeListener

protected ChangeListener hsbChangeListener

viewportChangeListener

protected ChangeListener viewportChangeListener

spPropertyChangeListener

protected PropertyChangeListener spPropertyChangeListener
Constructor Detail

BasicScrollPaneUI

public BasicScrollPaneUI()
Method Detail

createUI

public static ComponentUI createUI(JComponent x)
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.


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)
Description copied from class: ComponentUI
Returns the specified component's preferred size appropriate for the look and feel. If null is returned, the preferred 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 returns null.

Overrides:
getPreferredSize in class ComponentUI
Parameters:
c - the component whose preferred size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components
Returns:
null which indicates that the LayoutManager will compute the value
See Also:
JComponent.getPreferredSize()

getMinimumSize

public Dimension getMinimumSize(JComponent c)
Description copied from class: ComponentUI
Returns the specified component's minimum size appropriate for the look and feel. If null is returned, the minimum 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:
getMinimumSize in class ComponentUI
Parameters:
c - the component whose minimum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components
Returns:
the preferred size
See Also:
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 component whose maximum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components
Returns:
new Dimension(Short.MAX_VALUE, Short.MAX_VALUE)
See Also:
JComponent.getMaximumSize(), LayoutManager2.maximumLayoutSize(java.awt.Container)

installDefaults

protected void installDefaults(JScrollPane scrollpane)

installListeners

protected void installListeners(JScrollPane c)

installKeyboardActions

protected void installKeyboardActions(JScrollPane c)

installUI

public void installUI(JComponent x)
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:
x - the component where this UI delegate is being installed
See Also:
ComponentUI.uninstallUI(javax.swing.JComponent), JComponent.setUI(javax.swing.plaf.ComponentUI), JComponent.updateUI()

uninstallDefaults

protected void uninstallDefaults(JScrollPane c)

uninstallListeners

protected void uninstallListeners(JComponent c)

uninstallKeyboardActions

protected void uninstallKeyboardActions(JScrollPane c)

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()

syncScrollPaneWithViewport

protected void syncScrollPaneWithViewport()

createViewportChangeListener

protected ChangeListener createViewportChangeListener()

createHSBChangeListener

protected ChangeListener createHSBChangeListener()

createVSBChangeListener

protected ChangeListener createVSBChangeListener()

createMouseWheelListener

protected MouseWheelListener createMouseWheelListener()
Creates an instance of MouseWheelListener, which is added to the JScrollPane by installUI(). The returned MouseWheelListener is used to handle mouse wheel-driven scrolling.

Returns:
MouseWheelListener which implements wheel-driven scrolling
Since:
1.4
See Also:
installUI(javax.swing.JComponent), BasicScrollPaneUI.MouseWheelHandler

updateScrollBarDisplayPolicy

protected void updateScrollBarDisplayPolicy(PropertyChangeEvent e)

updateViewport

protected void updateViewport(PropertyChangeEvent e)

updateRowHeader

protected void updateRowHeader(PropertyChangeEvent e)

updateColumnHeader

protected void updateColumnHeader(PropertyChangeEvent e)

createPropertyChangeListener

protected PropertyChangeListener createPropertyChangeListener()
Creates an instance of PropertyChangeListener that's added to the JScrollPane by installUI(). Subclasses can override this method to return a custom PropertyChangeListener, e.g.
 class MyScrollPaneUI extends BasicScrollPaneUI {
    protected PropertyChangeListener createPropertyChangeListener() {
        return new MyPropertyChangeListener();
    }
    public class MyPropertyChangeListener extends PropertyChangeListener {
        public void propertyChange(PropertyChangeEvent e) {
            if (e.getPropertyName().equals("viewport")) {
                // do some extra work when the viewport changes
            }
            super.propertyChange(e);
        }
    }
 }
 

See Also:
PropertyChangeListener, installUI(javax.swing.JComponent)

JavaTM 2 Platform
Std. Ed. v1.4.2

Submit a bug or feature
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2003 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.


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