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:
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); } }
@version 1.60, 04/07/06 @author Arthur van Hoff @see java.awt.Container#add(String,Component) @see java.awt.ComponentOrientation @since JDK1.0
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