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 Class Summary

Modifier and Type Class Description
class  BasicScrollPaneUI.HSBChangeListener
Deprecated.
protected class  BasicScrollPaneUI.MouseWheelHandler
MouseWheelHandler is an inner class which implements the MouseWheelListener interface.
class  BasicScrollPaneUI.PropertyChangeHandler
Deprecated.
class  BasicScrollPaneUI.ViewportChangeHandler
Deprecated.
class  BasicScrollPaneUI.VSBChangeListener
Deprecated.

Field Summary

Modifier and Type Field Description
protected ChangeListener hsbChangeListener
ChangeListener installed on the horizontal scrollbar.
protected JScrollPane scrollpane
The instance of JScrollPane.
protected PropertyChangeListener spPropertyChangeListener
PropertyChangeListener installed on the scroll pane.
protected ChangeListener viewportChangeListener
ChangeListener installed on the viewport.
protected ChangeListener vsbChangeListener
ChangeListener installed on the vertical scrollbar.

Fields declared in 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

Constructor Description
BasicScrollPaneUI()
Constructs a BasicScrollPaneUI.

Method Summary

Modifier and Type Method Description
protected ChangeListener createHSBChangeListener()
Returns an instance of horizontal scroll bar ChangeListener.
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 a new instance of BasicScrollPaneUI.
protected ChangeListener createViewportChangeListener()
Returns an instance of viewport ChangeListener.
protected ChangeListener createVSBChangeListener()
Returns an instance of vertical scroll bar ChangeListener.
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)
Installs default properties.
protected void installKeyboardActions(JScrollPane c)
Registers keyboard actions.
protected void installListeners(JScrollPane c)
Registers listeners.
protected void syncScrollPaneWithViewport()
Synchronizes the JScrollPane with Viewport.
protected void uninstallDefaults(JScrollPane c)
Uninstalls default properties.
protected void uninstallKeyboardActions(JScrollPane c)
Unregisters keyboard actions.
protected void uninstallListeners(JComponent c)
Unregisters listeners.
protected void updateColumnHeader(PropertyChangeEvent e)
Updates column header.
protected void updateRowHeader(PropertyChangeEvent e)
Updates row header.
protected void updateScrollBarDisplayPolicy(PropertyChangeEvent e)
Updates a scroll bar display policy.
protected void updateViewport(PropertyChangeEvent e)
Updates viewport.

Methods declared in class javax.swing.plaf.ComponentUI

contains, getAccessibleChild, getAccessibleChildrenCount, getMinimumSize, getPreferredSize, installUI, paint, uninstallUI, update

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

scrollpane

protected JScrollPane scrollpane
The instance of JScrollPane.

vsbChangeListener

protected ChangeListener vsbChangeListener
ChangeListener installed on the vertical scrollbar.

hsbChangeListener

protected ChangeListener hsbChangeListener
ChangeListener installed on the horizontal scrollbar.

viewportChangeListener

protected ChangeListener viewportChangeListener
ChangeListener installed on the viewport.

spPropertyChangeListener

protected PropertyChangeListener spPropertyChangeListener
PropertyChangeListener installed on the scroll pane.

Constructor Details

BasicScrollPaneUI

public BasicScrollPaneUI()
Constructs a BasicScrollPaneUI.

Method Details

createUI

public static ComponentUI createUI(JComponent x)
Returns a new instance of BasicScrollPaneUI.
Parameters:
x - a component.
Returns:
a new instance of BasicScrollPaneUI

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:

installDefaults

protected void installDefaults(JScrollPane scrollpane)
Installs default properties.
Parameters:
scrollpane - an instance of JScrollPane

installListeners

protected void installListeners(JScrollPane c)
Registers listeners.
Parameters:
c - an instance of JScrollPane

installKeyboardActions

protected void installKeyboardActions(JScrollPane c)
Registers keyboard actions.
Parameters:
c - an instance of JScrollPane

uninstallDefaults

protected void uninstallDefaults(JScrollPane c)
Uninstalls default properties.
Parameters:
c - an instance of JScrollPane

uninstallListeners

protected void uninstallListeners(JComponent c)
Unregisters listeners.
Parameters:
c - a component

uninstallKeyboardActions

protected void uninstallKeyboardActions(JScrollPane c)
Unregisters keyboard actions.
Parameters:
c - an instance of JScrollPane

syncScrollPaneWithViewport

protected void syncScrollPaneWithViewport()
Synchronizes the JScrollPane with Viewport.

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:

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:

createViewportChangeListener

protected ChangeListener createViewportChangeListener()
Returns an instance of viewport ChangeListener.
Returns:
an instance of viewport ChangeListener

createHSBChangeListener

protected ChangeListener createHSBChangeListener()
Returns an instance of horizontal scroll bar ChangeListener.
Returns:
an instance of horizontal scroll bar ChangeListener

createVSBChangeListener

protected ChangeListener createVSBChangeListener()
Returns an instance of vertical scroll bar ChangeListener.
Returns:
an instance of vertical scroll bar ChangeListener

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:

updateScrollBarDisplayPolicy

protected void updateScrollBarDisplayPolicy(PropertyChangeEvent e)
Updates a scroll bar display policy.
Parameters:
e - the property change event

updateViewport

protected void updateViewport(PropertyChangeEvent e)
Updates viewport.
Parameters:
e - the property change event

updateRowHeader

protected void updateRowHeader(PropertyChangeEvent e)
Updates row header.
Parameters:
e - the property change event

updateColumnHeader

protected void updateColumnHeader(PropertyChangeEvent e)
Updates column header.
Parameters:
e - the property change event

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);
        }
    }
 }
Returns:
an instance of PropertyChangeListener
See Also:

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https://docs.oracle.com/en/java/javase/17/docs/api/java.desktop/javax/swing/plaf/basic/BasicScrollPaneUI.html