A border layout lays out a container, arranging and resizing
its components to fit in five regions:
North, South, East,
West, and Center. When adding a
component to a container with a border layout, use one of these
five names, for example:
Panel p = new Panel();
p.setLayout(new BorderLayout());
p.add(new Button("Okay"), "South");
As a convenience, BorderLayout interprets the absence of a string
specification the same as "Center":
Panel p2 = new Panel();
p2.setLayout(new BorderLayout());
p2.add(new TextArea()); // Same as p.add(new TextArea(), "Center");
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("North", new Button("North"));
add("South", new Button("South"));
add("East", new Button("East"));
add("West", new Button("West"));
add("Center", new Button("Center"));
}
}
The center layout constraint (middle of container).
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.
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 strings: "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.
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.
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.
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.
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 Southcomponents, 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.
Submit a bug or feature - Version 1.1.8 of Java Platform API Specification
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