BasicScrollPaneUI (Java Platform SE 8 )

java.lang.Object
- javax.swing.plaf.ComponentUI
- - javax.swing.plaf.ScrollPaneUI
  - - javax.swing.plaf.basic.BasicScrollPaneUI

All Implemented Interfaces:

ScrollPaneConstants

Direct Known Subclasses:

MetalScrollPaneUI, SynthScrollPaneUI
```
public class BasicScrollPaneUI
extends ScrollPaneUI
implements ScrollPaneConstants
```
A default L&F implementation of ScrollPaneUI.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`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

Fields
Modifier and Type	Field and Description
`protected ChangeListener`	`hsbChangeListener`
`protected JScrollPane`	`scrollpane`
`protected PropertyChangeListener`	`spPropertyChangeListener`
`protected ChangeListener`	`viewportChangeListener`
`protected ChangeListener`	`vsbChangeListener`

Constructor Summary

Constructors
Constructor and Description

BasicScrollPaneUI()

Constructors
Constructor and Description
`BasicScrollPaneUI()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`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)`
`protected ChangeListener`	`createViewportChangeListener()`
`protected ChangeListener`	`createVSBChangeListener()`
`int`	`getBaseline(JComponent c, int width, int height)` Returns the baseline.
`Component.BaselineResizeBehavior`	`getBaselineResizeBehavior(JComponent c)` Returns an enum indicating how the baseline of the component changes as the size changes.
`Dimension`	`getMaximumSize(JComponent c)` Returns the specified component's maximum 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 appropriately for the look and feel.
`void`	`paint(Graphics g, JComponent c)` Paints the specified component appropriately 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, getMinimumSize, getPreferredSize, 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)
```
  - 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)
  - 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 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:
    
    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()
```
  - getBaseline
```
public int getBaseline(JComponent c,
                       int width,
                       int height)
```
    Returns the baseline.
    
    Overrides:
    
    getBaseline in class ComponentUI
    
    Parameters:
    
    c - JComponent baseline is being requested for
    
    width - the width to get the baseline for
    
    height - the height to get the baseline for
    
    Returns:
    
    baseline or a value < 0 indicating there is no reasonable baseline
    
    Throws:
    
    NullPointerException - if c is null
    
    IllegalArgumentException - if width or height is < 0
    
    Since:
    
    1.6
    
    See Also:
    
    JComponent.getBaseline(int, int)
  - getBaselineResizeBehavior
```
public Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c)
```
    Returns an enum indicating how the baseline of the component changes as the size changes.
    
    Overrides:
    
    getBaselineResizeBehavior in class ComponentUI
    
    Parameters:
    
    c - JComponent to return baseline resize behavior for
    
    Returns:
    
    an enum indicating how the baseline changes as the component size changes
    
    Throws:
    
    NullPointerException - if c is null
    
    Since:
    
    1.6
    
    See Also:
    
    JComponent.getBaseline(int, int)
  - 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)

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Class BasicScrollPaneUI

Nested Class Summary

Field Summary

Fields inherited from interface javax.swing.ScrollPaneConstants

Constructor Summary

Method Summary

Methods inherited from class javax.swing.plaf.ComponentUI

Methods inherited from class java.lang.Object

Field Detail

scrollpane

vsbChangeListener

hsbChangeListener

viewportChangeListener

spPropertyChangeListener

Constructor Detail

BasicScrollPaneUI

Method Detail

createUI

paint

getMaximumSize

installDefaults

installListeners

installKeyboardActions

installUI

uninstallDefaults

uninstallListeners

uninstallKeyboardActions

uninstallUI

syncScrollPaneWithViewport

getBaseline

getBaselineResizeBehavior

createViewportChangeListener

createHSBChangeListener

createVSBChangeListener

createMouseWheelListener

updateScrollBarDisplayPolicy

updateViewport

updateRowHeader

updateColumnHeader

createPropertyChangeListener