BasicScrollPaneUI
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, SynthScrollPaneUI
public class BasicScrollPaneUI extends ScrollPaneUI implements ScrollPaneConstants
A default L&F implementation of ScrollPaneUI.
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. |
Fields
scrollpane
protected JScrollPane scrollpane
vsbChangeListener
protected ChangeListener vsbChangeListener
hsbChangeListener
protected ChangeListener hsbChangeListener
viewportChangeListener
protected ChangeListener viewportChangeListener
spPropertyChangeListener
protected PropertyChangeListener spPropertyChangeListener
Constructors
BasicScrollPaneUI
public BasicScrollPaneUI()
Methods
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 classComponentUI
- Parameters:
-
g
- theGraphics
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 classComponentUI
- 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:
- 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.
- Install a
LayoutManager
on the component if necessary. - Create/add any required sub-components to the component.
- Create/install event listeners on the component.
- Create/install a
PropertyChangeListener
on the component in order to detect and respond to component property changes appropriately. - Install keyboard UI (mnemonics, traversal, etc.) on the component.
- Initialize any appropriate instance data.
- Overrides:
-
installUI
in classComponentUI
- 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:
- Remove any UI-set borders from the component.
- Remove any UI-set layout managers on the component.
- Remove any UI-added sub-components from the component.
- Remove any UI-added event/property listeners from the component.
- Remove any UI-installed keyboard UI from the component.
- Nullify any allocated instance data objects to allow for GC.
- Overrides:
-
uninstallUI
in classComponentUI
- 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 classComponentUI
- 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
- ifc
isnull
-
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 classComponentUI
- Parameters:
-
c
-JComponent
to return baseline resize behavior for - Returns:
- an enum indicating how the baseline changes as the component size changes
- Throws:
-
NullPointerException
- ifc
isnull
- 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); } } }
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