This documentation differs from the official API. Jadeite adds extra features to the API including: variable font sizes, constructions examples, placeholders for classes and methods, and auto-generated “See Also” links. Additionally it is missing some items found in standard Javadoc documentation, including: generics type information, “Deprecated” tags and comments, “See Also” links, along with other minor differences. Please send any questions or feedback to bam@cs.cmu.edu.


java.awt
class BorderLayout

java.lang.Object extended by java.awt.BorderLayout
All Implemented Interfaces:
LayoutManager2, Serializable

Most common way to construct:

BorderLayout borderLayout1 = new BorderLayout();

Based on 79 examples


public class BorderLayout
extends Object
implements LayoutManager2, Serializable

A border layout lays out a container, arranging and resizing its components to fit in five regions: north, south, east, west, and center. Each region may contain no more than one component, and is identified by a corresponding constant: NORTH, SOUTH, EAST, WEST, and CENTER. When adding a component to a container with a border layout, use one of these five constants, for example:

    Panel p = new Panel();
    p.setLayout(new BorderLayout());
    p.add(new Button("Okay"), BorderLayout.SOUTH);
 
As a convenience, BorderLayout interprets the absence of a string specification the same as the constant CENTER:
    Panel p2 = new Panel();
    p2.setLayout(new BorderLayout());
    p2.add(new TextArea());  // Same as p.add(new TextArea(), BorderLayout.CENTER);
 

In addition, BorderLayout supports the relative positioning constants, PAGE_START, PAGE_END, LINE_START, and LINE_END. In a container whose ComponentOrientation is set to ComponentOrientation.LEFT_TO_RIGHT, these constants map to NORTH, SOUTH, WEST, and EAST, respectively.

For compatibility with previous releases, BorderLayout also includes the relative positioning constants BEFORE_FIRST_LINE, AFTER_LAST_LINE, BEFORE_LINE_BEGINS and AFTER_LINE_ENDS. These are equivalent to PAGE_START, PAGE_END, LINE_START and LINE_END respectively. For consistency with the relative positioning constants used by other components, the latter constants are preferred.

Mixing both absolute and relative positioning constants can lead to unpredicable results. If you use both types, the relative constants will take precedence. For example, if you add components using both the NORTH and PAGE_START constants in a container whose orientation is LEFT_TO_RIGHT, only the PAGE_START will be layed out.

NOTE: Currently (in the Java 2 platform v1.2), BorderLayout does not support vertical orientations. The isVertical setting on the container's ComponentOrientation is not respected.

The components are laid out according to their preferred sizes and the constraints of the container's size. The NORTH and SOUTH components may be stretched horizontally; the EAST and WEST components may be stretched vertically; the CENTER component may stretch both horizontally and vertically to fill any space left over.

Here is an example of five buttons in an applet laid out using the BorderLayout layout manager:

Diagram of an applet demonstrating BorderLayout. 
      Each section of the BorderLayout contains a Button corresponding to its position in the layout, one of: 
      North, West, Center, East, or South.

The code for this applet is as follows:


 import java.awt.*;
 import java.applet.Applet;

 public class buttonDir extends Applet {
   public void init() {
     setLayout(new BorderLayout());
     add(new Button("North"), BorderLayout.NORTH);
     add(new Button("South"), BorderLayout.SOUTH);
     add(new Button("East"), BorderLayout.EAST);
     add(new Button("West"), BorderLayout.WEST);
     add(new Button("Center"), BorderLayout.CENTER);
   }
 }
 


Field Summary
static String AFTER_LAST_LINE
          Synonym for PAGE_END.
static String AFTER_LINE_ENDS
          Synonym for LINE_END.
static String BEFORE_FIRST_LINE
          Synonym for PAGE_START.
static String BEFORE_LINE_BEGINS
          Synonym for LINE_START.
static String CENTER
          The center layout constraint (middle of container).
static String EAST
          The east layout constraint (right side of container).
static String LINE_END
          The component goes at the end of the line direction for the layout.
static String LINE_START
          The component goes at the beginning of the line direction for the layout.
static String NORTH
          The north layout constraint (top of container).
static String PAGE_END
          The component comes after the last line of the layout's content.
static String PAGE_START
          The component comes before the first line of the layout's content.
static String SOUTH
          The south layout constraint (bottom of container).
static String WEST
          The west layout constraint (left side of container).
 
Constructor Summary

          Constructs a new border layout with no gaps between components.
BorderLayout(int hgap, int vgap)

          Constructs a border layout with the specified gaps between components.
 
Method Summary
 void
addLayoutComponent(Component comp, Object constraints)

          Adds the specified component to the layout, using the specified constraint object.
 void

          
 Object

          Gets the constraints for the specified component
 int

          Returns the horizontal gap between components.
 float

          Returns the alignment along the x axis.
 float

          Returns the alignment along the y axis.
 Component
getLayoutComponent(Container target, Object constraints)

          Returns the component that corresponds to the given constraint location based on the target Container's component orientation.
 Component

          Gets the component that was added using the given constraint
 int

          Returns the vertical gap between components.
 void

          Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.
 void

          Lays out the container argument using this border layout.
 Dimension

          Returns the maximum dimensions for this layout given the components in the specified target container.
 Dimension

          Determines the minimum size of the target container using this layout manager.
 Dimension

          Determines the preferred size of the target container using this layout manager, based on the components in the container.
 void

          Removes the specified component from this border layout.
 void
setHgap(int hgap)

          Sets the horizontal gap between components.
 void
setVgap(int vgap)

          Sets the vertical gap between components.
 String

          Returns a string representation of the state of this border layout.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

AFTER_LAST_LINE

public static final String AFTER_LAST_LINE
Synonym for PAGE_END. Exists for compatibility with previous versions. PAGE_END is preferred.

AFTER_LINE_ENDS

public static final String AFTER_LINE_ENDS
Synonym for LINE_END. Exists for compatibility with previous versions. LINE_END is preferred.

BEFORE_FIRST_LINE

public static final String BEFORE_FIRST_LINE
Synonym for PAGE_START. Exists for compatibility with previous versions. PAGE_START is preferred.

BEFORE_LINE_BEGINS

public static final String BEFORE_LINE_BEGINS
Synonym for LINE_START. Exists for compatibility with previous versions. LINE_START is preferred.

CENTER

public static final String CENTER
The center layout constraint (middle of container).

EAST

public static final String EAST
The east layout constraint (right side of container).

LINE_END

public static final String LINE_END
The component goes at the end of the line direction for the layout. For Western, left-to-right and top-to-bottom orientations, this is equivalent to EAST.

LINE_START

public static final String LINE_START
The component goes at the beginning of the line direction for the layout. For Western, left-to-right and top-to-bottom orientations, this is equivalent to WEST.

NORTH

public static final String NORTH
The north layout constraint (top of container).

PAGE_END

public static final String PAGE_END
The component comes after the last line of the layout's content. For Western, left-to-right and top-to-bottom orientations, this is equivalent to SOUTH.

PAGE_START

public static final String PAGE_START
The component comes before the first line of the layout's content. For Western, left-to-right and top-to-bottom orientations, this is equivalent to NORTH.

SOUTH

public static final String SOUTH
The south layout constraint (bottom of container).

WEST

public static final String WEST
The west layout constraint (left side of container).
Constructor Detail

BorderLayout

public BorderLayout()
Constructs a new border layout with no gaps between components.


BorderLayout

public BorderLayout(int hgap,
                    int vgap)
Constructs a border layout with the specified gaps between components. The horizontal gap is specified by hgap and the vertical gap is specified by vgap.

Parameters:
hgap - the horizontal gap.
vgap - the vertical gap.
Method Detail

addLayoutComponent

public void addLayoutComponent(Component comp,
                               Object constraints)
Adds the specified component to the layout, using the specified constraint object. For border layouts, the constraint must be one of the following constants: NORTH, SOUTH, EAST, WEST, or CENTER.

Most applications do not call this method directly. This method is called when a component is added to a container using the Container.add method with the same argument types.

Parameters:
comp - the component to be added.
constraints - an object that specifies how and where the component is added to the layout.

addLayoutComponent

public void addLayoutComponent(String name,
                               Component comp)
Parameters:
name
comp

getConstraints

public Object getConstraints(Component comp)
Gets the constraints for the specified component

Parameters:
comp - the component to be queried
Returns:
the constraint for the specified component, or null if component is null or is not present in this layout

getHgap

public int getHgap()
Returns the horizontal gap between components.


getLayoutAlignmentX

public float getLayoutAlignmentX(Container parent)
Returns the alignment along the x axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.

Parameters:
parent

getLayoutAlignmentY

public float getLayoutAlignmentY(Container parent)
Returns the alignment along the y axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.

Parameters:
parent

getLayoutComponent

public Component getLayoutComponent(Container target,
                                    Object constraints)
Returns the component that corresponds to the given constraint location based on the target Container's component orientation. Components added with the relative constraints PAGE_START, PAGE_END, LINE_START, and LINE_END take precedence over components added with the explicit constraints NORTH, SOUTH, WEST, and EAST. The Container's component orientation is used to determine the location of components added with LINE_START and LINE_END.

Parameters:
target - the {@code Container} used to obtain the constraint location based on the target {@code Container}'s component orientation.
constraints - the desired absolute position, one of CENTER, NORTH, SOUTH, EAST, WEST
Returns:
the component at the given location, or null if the location is empty

getLayoutComponent

public Component getLayoutComponent(Object constraints)
Gets the component that was added using the given constraint

Parameters:
constraints - the desired constraint, one of CENTER, NORTH, SOUTH, WEST, EAST, PAGE_START, PAGE_END, LINE_START, LINE_END
Returns:
the component at the given location, or null if the location is empty

getVgap

public int getVgap()
Returns the vertical gap between components.


invalidateLayout

public void invalidateLayout(Container target)
Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.

Parameters:
target

layoutContainer

public void layoutContainer(Container target)
Lays out the container argument using this border layout.

This method actually reshapes the components in the specified container in order to satisfy the constraints of this BorderLayout object. The NORTH and SOUTH components, if any, are placed at the top and bottom of the container, respectively. The WEST and EAST components are then placed on the left and right, respectively. Finally, the CENTER object is placed in any remaining space in the middle.

Most applications do not call this method directly. This method is called when a container calls its doLayout method.

Parameters:
target - the container in which to do the layout.

maximumLayoutSize

public Dimension maximumLayoutSize(Container target)
Returns the maximum dimensions for this layout given the components in the specified target container.

Parameters:
target - the component which needs to be laid out

minimumLayoutSize

public Dimension minimumLayoutSize(Container target)
Determines the minimum size of the target container using this layout manager.

This method is called when a container calls its getMinimumSize method. Most applications do not call this method directly.

Parameters:
target - the container in which to do the layout.
Returns:
the minimum dimensions needed to lay out the subcomponents of the specified container.

preferredLayoutSize

public Dimension preferredLayoutSize(Container target)
Determines the preferred size of the target container using this layout manager, based on the components in the container.

Most applications do not call this method directly. This method is called when a container calls its getPreferredSize method.

Parameters:
target - the container in which to do the layout.
Returns:
the preferred dimensions to lay out the subcomponents of the specified container.

removeLayoutComponent

public void removeLayoutComponent(Component comp)
Removes the specified component from this border layout. This method is called when a container calls its remove or removeAll methods. Most applications do not call this method directly.

Parameters:
comp - the component to be removed.

setHgap

public void setHgap(int hgap)
Sets the horizontal gap between components.

Parameters:
hgap - the horizontal gap between components

setVgap

public void setVgap(int vgap)
Sets the vertical gap between components.

Parameters:
vgap - the vertical gap between components

toString

public String toString()
Returns a string representation of the state of this border layout.

Overrides:
toString in class Object
Returns:
a string representation of this border layout.


This documentation differs from the official API. Jadeite adds extra features to the API including: variable font sizes, constructions examples, placeholders for classes and methods, and auto-generated “See Also” links. Additionally it is missing some items found in standard Javadoc documentation, including: generics type information, “Deprecated” tags and comments, “See Also” links, along with other minor differences. Please send any questions or feedback to bam@cs.cmu.edu.
This page displays the Jadeite version of the documention, which is derived from the offical documentation that contains this copyright notice:
Copyright 2008 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.
The official Sun™ documentation can be found here at http://java.sun.com/javase/6/docs/api/.