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Class com.sun.java.swing.BoxLayout 

java.lang.Object
   |
   +----com.sun.java.swing.BoxLayout
public class BoxLayout
extends Object
implements LayoutManager2, Serializable
A layout manager that places each of its managed components from left to right or from top to bottom. When you create a BoxLayout, you specify whether its major axis is the X axis (which means left to right placement) or Y axis (top to bottom placement). Components are arranged from left to right (or top to bottom), in the same order as they were added to the container.

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Instead of using BoxLayout directly, many programs use the Box class. The Box class provides a lightweight container that uses a BoxLayout. Box also provides handy methods to help you use BoxLayout well.

BoxLayout attempts to arrange components at their preferred widths (for left to right layout) or heights (for top to bottom layout). For a left to right layout, if not all the components are the same height, BoxLayout attempts to make all the components as high as the highest component. If that's not possible for a particular component, then BoxLayout aligns that component vertically, according to the component's Y alignment. By default, a component has an Y alignment of 0.5, which means that the vertical center of the component should have the same Y coordinate as the vertical centers of other components with 0.5 Y alignment.

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Similarly, for a vertical layout, BoxLayout attempts to make all components in the column as wide as the widest component; if that fails, it aligns them horizontally according to their X alignments.

See Also:
Box, getAlignmentX, getAlignmentY

Variable Index

o X_AXIS
Specifies that components should be laid out left to right.
o Y_AXIS
Specifies that components should be laid out top to buttom.

Constructor Index

o BoxLayout(Container, int)
Creates a layout manager that will lay out components either left to right or top to bottom, as specified in the axis parameter.

Method Index

o addLayoutComponent(Component, Object)
Not used by this class.
o addLayoutComponent(String, Component)
Not used by this class.
o getLayoutAlignmentX(Container)
Returns the alignment along the X axis for the container.
o getLayoutAlignmentY(Container)
Returns the alignment along the Y axis for the container.
o invalidateLayout(Container)
Indicates that a child has changed its layout related information, and thus any cached calculations should be flushed.
o layoutContainer(Container)
Called by the AWT when the specified container needs to be laid out.
o maximumLayoutSize(Container)
Returns the minimum dimensions needed to lay out the components contained in the specified target container.
o minimumLayoutSize(Container)
Returns the minimum dimensions needed to layout the components contained in the specified target container.
o preferredLayoutSize(Container)
Returns the preferred dimensions for this layout, given the components in the specified target container.
o removeLayoutComponent(Component)
Not used by this class.

Variables

o X_AXIS 
 public static final int X_AXIS
Specifies that components should be laid out left to right.

o Y_AXIS 
 public static final int Y_AXIS
Specifies that components should be laid out top to buttom.

Constructors

o BoxLayout 
 public BoxLayout(Container target,
                  int axis)
Creates a layout manager that will lay out components either left to right or top to bottom, as specified in the axis parameter.

Parameters:
target - the container that needs to be laid out
axis - the axis to lay out components along. For left-to-right layout, specify BoxLayout.X_AXIS; for top-to-bottom layout, specify BoxLayout.Y_AXIS
Throws: AWTError
if the value of axis is invalid

Methods

o invalidateLayout 
 public void invalidateLayout(Container target)
Indicates that a child has changed its layout related information, and thus any cached calculations should be flushed.

Parameters:
target - the affected container
Throws: AWTError
if the target isn't the container specified to the BoxLayout constructor
o addLayoutComponent 
 public void addLayoutComponent(String name,
                                Component comp)
Not used by this class.

o removeLayoutComponent 
 public void removeLayoutComponent(Component comp)
Not used by this class.

o addLayoutComponent 
 public void addLayoutComponent(Component comp,
                                Object constraints)
Not used by this class.

o preferredLayoutSize 
 public Dimension preferredLayoutSize(Container target)
Returns the preferred dimensions for this layout, given the components in the specified target container.

Parameters:
target - the container that needs to be laid out
Throws: AWTError
if the target isn't the container specified to the BoxLayout constructor
See Also:
Container, minimumLayoutSize, maximumLayoutSize
o minimumLayoutSize 
 public Dimension minimumLayoutSize(Container target)
Returns the minimum dimensions needed to layout the components contained in the specified target container.

Parameters:
target - the container that needs to be laid out
Throws: AWTError
if the target isn't the container specified to the BoxLayout constructor
See Also:
preferredLayoutSize, maximumLayoutSize
o maximumLayoutSize 
 public Dimension maximumLayoutSize(Container target)
Returns the minimum dimensions needed to lay out the components contained in the specified target container.

Parameters:
target - the container that needs to be laid out
Throws: AWTError
if the target isn't the container specified to the BoxLayout constructor
See Also:
preferredLayoutSize, minimumLayoutSize
o getLayoutAlignmentX 
 public float getLayoutAlignmentX(Container target)
Returns the alignment along the X axis for the container. If the box is horizontal, the default alignment will be returned. Otherwise, the alignment needed to place the children along the X axis will be returned.

Parameters:
target - the container that needs to be laid out
Throws: AWTError
if the target isn't the container specified to the BoxLayout constructor
o getLayoutAlignmentY 
 public float getLayoutAlignmentY(Container target)
Returns the alignment along the Y axis for the container. If the box is vertical, the default alignment will be returned. Otherwise, the alignment needed to place the children along the Y axis will be returned.

Parameters:
target - the container that needs to be laid out
Throws: AWTError
if the target isn't the container specified to the BoxLayout constructor
o layoutContainer 
 public void layoutContainer(Container target)
Called by the AWT when the specified container needs to be laid out.

Parameters:
target - the container to lay out
Throws: AWTError
if the target isn't the container specified to the BoxLayout constructor 
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