javax.swing.plaf.basic
Class BasicScrollPaneUI

java.lang.Object
  javax.swing.plaf.ComponentUI
      javax.swing.plaf.ScrollPaneUI
          javax.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)