Java™ Platform
Standard Ed. 6

javax.swing
Class ScrollPaneLayout

java.lang.Object
  extended by javax.swing.ScrollPaneLayout
All Implemented Interfaces:
LayoutManager, Serializable, ScrollPaneConstants
Direct Known Subclasses:
ScrollPaneLayout.UIResource

public class ScrollPaneLayout
extends Object
implements LayoutManager, ScrollPaneConstants, Serializable

The layout manager used by JScrollPane. JScrollPaneLayout is responsible for nine components: a viewport, two scrollbars, a row header, a column header, and four "corner" components.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeansTM has been added to the java.beans package. Please see XMLEncoder.

See Also:
JScrollPane, JViewport

Nested Class Summary
static class ScrollPaneLayout.UIResource
          The UI resource version of ScrollPaneLayout.
 
Field Summary
protected  JViewport colHead
          The column header child.
protected  JScrollBar hsb
          The scrollpane's horizontal scrollbar child.
protected  int hsbPolicy
          The display policy for the horizontal scrollbar.
protected  Component lowerLeft
          The component to display in the lower left corner.
protected  Component lowerRight
          The component to display in the lower right corner.
protected  JViewport rowHead
          The row header child.
protected  Component upperLeft
          The component to display in the upper left corner.
protected  Component upperRight
          The component to display in the upper right corner.
protected  JViewport viewport
          The scrollpane's viewport child.
protected  JScrollBar vsb
          The scrollpane's vertical scrollbar child.
protected  int vsbPolicy
          The display policy for the vertical scrollbar.
 
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
ScrollPaneLayout()
           
 
Method Summary
 void addLayoutComponent(String s, Component c)
          Adds the specified component to the layout.
protected  Component addSingletonComponent(Component oldC, Component newC)
          Removes an existing component.
 JViewport getColumnHeader()
          Returns the JViewport object that is the column header.
 Component getCorner(String key)
          Returns the Component at the specified corner.
 JScrollBar getHorizontalScrollBar()
          Returns the JScrollBar object that handles horizontal scrolling.
 int getHorizontalScrollBarPolicy()
          Returns the horizontal scrollbar-display policy.
 JViewport getRowHeader()
          Returns the JViewport object that is the row header.
 JScrollBar getVerticalScrollBar()
          Returns the JScrollBar object that handles vertical scrolling.
 int getVerticalScrollBarPolicy()
          Returns the vertical scrollbar-display policy.
 JViewport getViewport()
          Returns the JViewport object that displays the scrollable contents.
 Rectangle getViewportBorderBounds(JScrollPane scrollpane)
          Deprecated. As of JDK version Swing1.1 replaced by JScrollPane.getViewportBorderBounds().
 void layoutContainer(Container parent)
          Lays out the scrollpane.
 Dimension minimumLayoutSize(Container parent)
          The minimum size of a ScrollPane is the size of the insets plus minimum size of the viewport, plus the scrollpane's viewportBorder insets, plus the minimum size of the visible headers, plus the minimum size of the scrollbars whose displayPolicy isn't NEVER.
 Dimension preferredLayoutSize(Container parent)
          The preferred size of a ScrollPane is the size of the insets, plus the preferred size of the viewport, plus the preferred size of the visible headers, plus the preferred size of the scrollbars that will appear given the current view and the current scrollbar displayPolicies.
 void removeLayoutComponent(Component c)
          Removes the specified component from the layout.
 void setHorizontalScrollBarPolicy(int x)
          Sets the horizontal scrollbar-display policy.
 void setVerticalScrollBarPolicy(int x)
          Sets the vertical scrollbar-display policy.
 void syncWithScrollPane(JScrollPane sp)
          This method is invoked after the ScrollPaneLayout is set as the LayoutManager of a JScrollPane.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

viewport

protected JViewport viewport
The scrollpane's viewport child. Default is an empty JViewport.

See Also:
JScrollPane.setViewport(javax.swing.JViewport)

vsb

protected JScrollBar vsb
The scrollpane's vertical scrollbar child. Default is a JScrollBar.

See Also:
JScrollPane.setVerticalScrollBar(javax.swing.JScrollBar)

hsb

protected JScrollBar hsb
The scrollpane's horizontal scrollbar child. Default is a JScrollBar.

See Also:
JScrollPane.setHorizontalScrollBar(javax.swing.JScrollBar)

rowHead

protected JViewport rowHead
The row header child. Default is null.

See Also:
JScrollPane.setRowHeader(javax.swing.JViewport)

colHead

protected JViewport colHead
The column header child. Default is null.

See Also:
JScrollPane.setColumnHeader(javax.swing.JViewport)

lowerLeft

protected Component lowerLeft
The component to display in the lower left corner. Default is null.

See Also:
JScrollPane.setCorner(java.lang.String, java.awt.Component)

lowerRight

protected Component lowerRight
The component to display in the lower right corner. Default is null.

See Also:
JScrollPane.setCorner(java.lang.String, java.awt.Component)

upperLeft

protected Component upperLeft
The component to display in the upper left corner. Default is null.

See Also:
JScrollPane.setCorner(java.lang.String, java.awt.Component)

upperRight

protected Component upperRight
The component to display in the upper right corner. Default is null.

See Also:
JScrollPane.setCorner(java.lang.String, java.awt.Component)

vsbPolicy

protected int vsbPolicy
The display policy for the vertical scrollbar. The default is ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED.

This field is obsolete, please use the JScrollPane field instead.

See Also:
JScrollPane.setVerticalScrollBarPolicy(int)

hsbPolicy

protected int hsbPolicy
The display policy for the horizontal scrollbar. The default is ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED.

This field is obsolete, please use the JScrollPane field instead.

See Also:
JScrollPane.setHorizontalScrollBarPolicy(int)
Constructor Detail

ScrollPaneLayout

public ScrollPaneLayout()
Method Detail

syncWithScrollPane

public void syncWithScrollPane(JScrollPane sp)
This method is invoked after the ScrollPaneLayout is set as the LayoutManager of a JScrollPane. It initializes all of the internal fields that are ordinarily set by addLayoutComponent. For example:
 ScrollPaneLayout mySPLayout = new ScrollPanelLayout() {
     public void layoutContainer(Container p) {
         super.layoutContainer(p);
         // do some extra work here ...
     }
 };
 scrollpane.setLayout(mySPLayout):
 


addSingletonComponent

protected Component addSingletonComponent(Component oldC,
                                          Component newC)
Removes an existing component. When a new component, such as the left corner, or vertical scrollbar, is added, the old one, if it exists, must be removed.

This method returns newC. If oldC is not equal to newC and is non-null, it will be removed from its parent.

Parameters:
oldC - the Component to replace
newC - the Component to add
Returns:
the newC

addLayoutComponent

public void addLayoutComponent(String s,
                               Component c)
Adds the specified component to the layout. The layout is identified using one of:

Specified by:
addLayoutComponent in interface LayoutManager
Parameters:
s - the component identifier
c - the the component to be added
Throws:
IllegalArgumentException - if s is an invalid key

removeLayoutComponent

public void removeLayoutComponent(Component c)
Removes the specified component from the layout.

Specified by:
removeLayoutComponent in interface LayoutManager
Parameters:
c - the component to remove

getVerticalScrollBarPolicy

public int getVerticalScrollBarPolicy()
Returns the vertical scrollbar-display policy.

Returns:
an integer giving the display policy
See Also:
setVerticalScrollBarPolicy(int)

setVerticalScrollBarPolicy

public void setVerticalScrollBarPolicy(int x)
Sets the vertical scrollbar-display policy. The options are: Note: Applications should use the JScrollPane version of this method. It only exists for backwards compatibility with the Swing 1.0.2 (and earlier) versions of this class.

Parameters:
x - an integer giving the display policy
Throws:
IllegalArgumentException - if x is an invalid vertical scroll bar policy, as listed above

getHorizontalScrollBarPolicy

public int getHorizontalScrollBarPolicy()
Returns the horizontal scrollbar-display policy.

Returns:
an integer giving the display policy
See Also:
setHorizontalScrollBarPolicy(int)

setHorizontalScrollBarPolicy

public void setHorizontalScrollBarPolicy(int x)
Sets the horizontal scrollbar-display policy. The options are: Note: Applications should use the JScrollPane version of this method. It only exists for backwards compatibility with the Swing 1.0.2 (and earlier) versions of this class.

Parameters:
x - an int giving the display policy
Throws:
IllegalArgumentException - if x is not a valid horizontal scrollbar policy, as listed above

getViewport

public JViewport getViewport()
Returns the JViewport object that displays the scrollable contents.

Returns:
the JViewport object that displays the scrollable contents
See Also:
JScrollPane.getViewport()

getHorizontalScrollBar

public JScrollBar getHorizontalScrollBar()
Returns the JScrollBar object that handles horizontal scrolling.

Returns:
the JScrollBar object that handles horizontal scrolling
See Also:
JScrollPane.getHorizontalScrollBar()

getVerticalScrollBar

public JScrollBar getVerticalScrollBar()
Returns the JScrollBar object that handles vertical scrolling.

Returns:
the JScrollBar object that handles vertical scrolling
See Also:
JScrollPane.getVerticalScrollBar()

getRowHeader

public JViewport getRowHeader()
Returns the JViewport object that is the row header.

Returns:
the JViewport object that is the row header
See Also:
JScrollPane.getRowHeader()

getColumnHeader

public JViewport getColumnHeader()
Returns the JViewport object that is the column header.

Returns:
the JViewport object that is the column header
See Also:
JScrollPane.getColumnHeader()

getCorner

public Component getCorner(String key)
Returns the Component at the specified corner.

Parameters:
key - the String specifying the corner
Returns:
the Component at the specified corner, as defined in ScrollPaneConstants; if key is not one of the four corners, null is returned
See Also:
JScrollPane.getCorner(java.lang.String)

preferredLayoutSize

public Dimension preferredLayoutSize(Container parent)
The preferred size of a ScrollPane is the size of the insets, plus the preferred size of the viewport, plus the preferred size of the visible headers, plus the preferred size of the scrollbars that will appear given the current view and the current scrollbar displayPolicies.

Note that the rowHeader is calculated as part of the preferred width and the colHeader is calculated as part of the preferred size.

Specified by:
preferredLayoutSize in interface LayoutManager
Parameters:
parent - the Container that will be laid out
Returns:
a Dimension object specifying the preferred size of the viewport and any scrollbars
See Also:
ViewportLayout, LayoutManager

minimumLayoutSize

public Dimension minimumLayoutSize(Container parent)
The minimum size of a ScrollPane is the size of the insets plus minimum size of the viewport, plus the scrollpane's viewportBorder insets, plus the minimum size of the visible headers, plus the minimum size of the scrollbars whose displayPolicy isn't NEVER.

Specified by:
minimumLayoutSize in interface LayoutManager
Parameters:
parent - the Container that will be laid out
Returns:
a Dimension object specifying the minimum size
See Also:
LayoutManager.preferredLayoutSize(java.awt.Container)

layoutContainer

public void layoutContainer(Container parent)
Lays out the scrollpane. The positioning of components depends on the following constraints:

Specified by:
layoutContainer in interface LayoutManager
Parameters:
parent - the Container to lay out

getViewportBorderBounds

@Deprecated
public Rectangle getViewportBorderBounds(JScrollPane scrollpane)
Deprecated. As of JDK version Swing1.1 replaced by JScrollPane.getViewportBorderBounds().

Returns the bounds of the border around the specified scroll pane's viewport.

Returns:
the size and position of the viewport border

Java™ Platform
Standard Ed. 6

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