Class java.awt.BorderLayout
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Class java.awt.BorderLayout
Object
|
+----java.awt.BorderLayout
- 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
. 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"));
}
}
- Version:
- 1.27 02/11/97
- Author:
- Arthur van Hoff
- Since:
- JDK1.0
- See Also:
- java.awt.Container.add(String, Component)
-
CENTER
- The center layout constraint (middle of container).
-
EAST
- The east layout constraint (left side of container).
-
NORTH
- The north layout constraint (top of container).
-
SOUTH
- The south layout constraint (bottom of container).
-
WEST
- The west layout constraint (right side of container).
-
java.awt.BorderLayout()
- Constructs a new border layout with
no gaps between components.
-
java.awt.BorderLayout(int, int)
- Constructs a border layout with the specified gaps
between components.
-
addLayoutComponent(Component, Object)
- Adds the specified component to the layout, using the specified
constraint object.
-
addLayoutComponent(String, Component)
-
-
getHgap()
- Returns the horizontal gap between components.
-
getLayoutAlignmentX(Container)
- Returns the alignment along the x axis.
-
getLayoutAlignmentY(Container)
- Returns the alignment along the y axis.
-
getVgap()
- Returns the vertical gap between components.
-
invalidateLayout(Container)
- Invalidates the layout, indicating that if the layout manager
has cached information it should be discarded.
-
layoutContainer(Container)
- Lays out the container argument using this border layout.
-
maximumLayoutSize(Container)
- Returns the maximum dimensions for this layout given the components
in the specified target container.
-
minimumLayoutSize(Container)
- Determines the minimum size of the
target
container
using this layout manager.
-
preferredLayoutSize(Container)
- Determines the preferred size of the
target
container using this layout manager, based on the components
in the container.
-
removeLayoutComponent(Component)
- Removes the specified component from this border layout.
-
setHgap(int)
- Sets the horizontal gap between components.
-
setVgap(int)
- Sets the vertical gap between components.
-
toString()
- Returns a string representation of the state of this border layout.
CENTER
public static final java.lang.String CENTER
- The center layout constraint (middle of container).
EAST
public static final java.lang.String EAST
- The east layout constraint (left side of container).
NORTH
public static final java.lang.String NORTH
- The north layout constraint (top of container).
SOUTH
public static final java.lang.String SOUTH
- The south layout constraint (bottom of container).
WEST
public static final java.lang.String WEST
- The west layout constraint (right side of container).
BorderLayout
public BorderLayout()
- Constructs a new border layout with
no gaps between components.
- Since:
- JDK1.0
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.
- Since:
- JDK1.0
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 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.
- Throws: IllegalArgumentException
- if the constraint object is not
a string, or if it not one of the five specified strings.
- Since:
- JDK1.1
- See Also:
- add(java.awt.Component, java.lang.Object)
addLayoutComponent
public void addLayoutComponent(String name,
Component comp)
- Note: addLayoutComponent() is deprecated.
replaced by
addLayoutComponent(Component, Object)
.
-
getHgap
public int getHgap()
- Returns the horizontal gap between components.
- Since:
- JDK1.1
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.
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.
getVgap
public int getVgap()
- Returns the vertical gap between components.
- Since:
- JDK1.1
invalidateLayout
public void invalidateLayout(Container target)
- Invalidates the layout, indicating that if the layout manager
has cached information it should be discarded.
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.
- Since:
- JDK1.0
- See Also:
- Container, doLayout()
maximumLayoutSize
public java.awt.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
- See Also:
- Container, minimumLayoutSize, preferredLayoutSize
minimumLayoutSize
public java.awt.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.
- Since:
- JDK1.0
- See Also:
- Container, preferredLayoutSize, getMinimumSize()
preferredLayoutSize
public java.awt.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.
- Since:
- JDK1.0
- See Also:
- Container, minimumLayoutSize, getPreferredSize()
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.
- Since:
- JDK1.0
- See Also:
- remove(java.awt.Component), removeAll()
setHgap
public void setHgap(int hgap)
- Sets the horizontal gap between components.
- Parameters:
- hgap - the horizontal gap between components
- Since:
- JDK1.1
setVgap
public void setVgap(int vgap)
- Sets the vertical gap between components.
- Parameters:
- vgap - the vertical gap between components
- Since:
- JDK1.1
toString
public java.lang.String toString()
- Returns a string representation of the state of this border layout.
- Returns:
- a string representation of this border layout.
- Overrides:
- toString in class Object
- Since:
- JDK1.0
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