Class BorderLayout
- All Implemented Interfaces:
- LayoutManager,- LayoutManager2,- Serializable
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
 unpredictable 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 laid out.
 
 NOTE: Currently,
 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);
   }
 }
 - Since:
- 1.0
- See Also:
- 
Field SummaryFieldsModifier and TypeFieldDescriptionstatic final StringSynonym for PAGE_END.static final StringSynonym for LINE_END.static final StringSynonym for PAGE_START.static final StringSynonym for LINE_START.static final StringThe center layout constraint (middle of container).static final StringThe east layout constraint (right side of container).static final StringThe component goes at the end of the line direction for the layout.static final StringThe component goes at the beginning of the line direction for the layout.static final StringThe north layout constraint (top of container).static final StringThe component comes after the last line of the layout's content.static final StringThe component comes before the first line of the layout's content.static final StringThe south layout constraint (bottom of container).static final StringThe west layout constraint (left side of container).
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Constructor SummaryConstructorsConstructorDescriptionConstructs 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 SummaryModifier and TypeMethodDescriptionvoidaddLayoutComponent(Component comp, Object constraints) Adds the specified component to the layout, using the specified constraint object.voidaddLayoutComponent(String name, Component comp) Deprecated.getConstraints(Component comp) Gets the constraints for the specified componentintgetHgap()Returns the horizontal gap between components.floatgetLayoutAlignmentX(Container parent) Returns the alignment along the x axis.floatgetLayoutAlignmentY(Container parent) Returns the alignment along the y axis.getLayoutComponent(Container target, Object constraints) Returns the component that corresponds to the given constraint location based on the targetContainer's component orientation.getLayoutComponent(Object constraints) Gets the component that was added using the given constraintintgetVgap()Returns the vertical gap between components.voidinvalidateLayout(Container target) Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.voidlayoutContainer(Container target) Lays out the container argument using this border layout.maximumLayoutSize(Container target) Returns the maximum dimensions for this layout given the components in the specified target container.minimumLayoutSize(Container target) Determines the minimum size of thetargetcontainer using this layout manager.preferredLayoutSize(Container target) Determines the preferred size of thetargetcontainer using this layout manager, based on the components in the container.voidRemoves the specified component from this border layout.voidsetHgap(int hgap) Sets the horizontal gap between components.voidsetVgap(int vgap) Sets the vertical gap between components.toString()Returns a string representation of the state of this border layout.
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Field Details- 
NORTH
- 
SOUTH
- 
EAST
- 
WEST
- 
CENTER
- 
BEFORE_FIRST_LINESynonym for PAGE_START. Exists for compatibility with previous versions. PAGE_START is preferred.- Since:
- 1.2
- See Also:
 
- 
AFTER_LAST_LINESynonym for PAGE_END. Exists for compatibility with previous versions. PAGE_END is preferred.- Since:
- 1.2
- See Also:
 
- 
BEFORE_LINE_BEGINSSynonym for LINE_START. Exists for compatibility with previous versions. LINE_START is preferred.- Since:
- 1.2
- See Also:
 
- 
AFTER_LINE_ENDSSynonym for LINE_END. Exists for compatibility with previous versions. LINE_END is preferred.- Since:
- 1.2
- See Also:
 
- 
PAGE_STARTThe 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.- Since:
- 1.4
- See Also:
 
- 
PAGE_ENDThe 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.- Since:
- 1.4
- See Also:
 
- 
LINE_STARTThe 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.- Since:
- 1.4
- See Also:
 
- 
LINE_ENDThe 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.- Since:
- 1.4
- See Also:
 
 
- 
- 
Constructor Details- 
BorderLayoutpublic BorderLayout()Constructs a new border layout with no gaps between components.
- 
BorderLayoutpublic BorderLayout(int hgap, int vgap) Constructs a border layout with the specified gaps between components. The horizontal gap is specified byhgapand the vertical gap is specified byvgap.- Parameters:
- hgap- the horizontal gap.
- vgap- the vertical gap.
 
 
- 
- 
Method Details- 
getHgappublic int getHgap()Returns the horizontal gap between components.- Returns:
- the horizontal gap between components
- Since:
- 1.1
 
- 
setHgappublic void setHgap(int hgap) Sets the horizontal gap between components.- Parameters:
- hgap- the horizontal gap between components
- Since:
- 1.1
 
- 
getVgappublic int getVgap()Returns the vertical gap between components.- Returns:
- the vertical gap between components
- Since:
- 1.1
 
- 
setVgappublic void setVgap(int vgap) Sets the vertical gap between components.- Parameters:
- vgap- the vertical gap between components
- Since:
- 1.1
 
- 
addLayoutComponentAdds 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, orCENTER.Most applications do not call this method directly. This method is called when a component is added to a container using the Container.addmethod with the same argument types.- Specified by:
- addLayoutComponentin interface- LayoutManager2
- 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 constants.
- Since:
- 1.1
- See Also:
 
- 
addLayoutComponentDeprecated.replaced byaddLayoutComponent(Component, Object).Description copied from interface:LayoutManagerIf the layout manager uses a per-component string, adds the componentcompto the layout, associating it with the string specified byname.- Specified by:
- addLayoutComponentin interface- LayoutManager
- Parameters:
- name- the string to be associated with the component
- comp- the component to be added
 
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removeLayoutComponentRemoves the specified component from this border layout. This method is called when a container calls itsremoveorremoveAllmethods. Most applications do not call this method directly.- Specified by:
- removeLayoutComponentin interface- LayoutManager
- Parameters:
- comp- the component to be removed.
- See Also:
 
- 
getLayoutComponentGets 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 nullif the location is empty
- Throws:
- IllegalArgumentException- if the constraint object is not one of the nine specified constants
- Since:
- 1.5
- See Also:
 
- 
getLayoutComponentReturns the component that corresponds to the given constraint location based on the targetContainer's component orientation. Components added with the relative constraintsPAGE_START,PAGE_END,LINE_START, andLINE_ENDtake precedence over components added with the explicit constraintsNORTH,SOUTH,WEST, andEAST. TheContainer's component orientation is used to determine the location of components added withLINE_STARTandLINE_END.- Parameters:
- target- the- Containerused to obtain the constraint location based on the target- Container's component orientation.
- constraints- the desired absolute position, one of- CENTER,- NORTH,- SOUTH,- EAST,- WEST
- Returns:
- the component at the given location, or nullif the location is empty
- Throws:
- IllegalArgumentException- if the constraint object is not one of the five specified constants
- NullPointerException- if the target parameter is null
- Since:
- 1.5
- See Also:
 
- 
getConstraints
- 
minimumLayoutSizeDetermines the minimum size of thetargetcontainer using this layout manager.This method is called when a container calls its getMinimumSizemethod. Most applications do not call this method directly.- Specified by:
- minimumLayoutSizein interface- LayoutManager
- Parameters:
- target- the container in which to do the layout.
- Returns:
- the minimum dimensions needed to lay out the subcomponents of the specified container.
- See Also:
 
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preferredLayoutSizeDetermines the preferred size of thetargetcontainer 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 getPreferredSizemethod.- Specified by:
- preferredLayoutSizein interface- LayoutManager
- Parameters:
- target- the container in which to do the layout.
- Returns:
- the preferred dimensions to lay out the subcomponents of the specified container.
- See Also:
 
- 
maximumLayoutSizeReturns the maximum dimensions for this layout given the components in the specified target container.- Specified by:
- maximumLayoutSizein interface- LayoutManager2
- Parameters:
- target- the component which needs to be laid out
- Returns:
- the maximum size of the container
- See Also:
 
- 
getLayoutAlignmentXReturns 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.- Specified by:
- getLayoutAlignmentXin interface- LayoutManager2
- Parameters:
- parent- the target container
- Returns:
- the x-axis alignment preference
 
- 
getLayoutAlignmentYReturns 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.- Specified by:
- getLayoutAlignmentYin interface- LayoutManager2
- Parameters:
- parent- the target container
- Returns:
- the y-axis alignment preference
 
- 
invalidateLayoutInvalidates the layout, indicating that if the layout manager has cached information it should be discarded.- Specified by:
- invalidateLayoutin interface- LayoutManager2
- Parameters:
- target- the target container
 
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layoutContainerLays 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 BorderLayoutobject. TheNORTHandSOUTHcomponents, if any, are placed at the top and bottom of the container, respectively. TheWESTandEASTcomponents are then placed on the left and right, respectively. Finally, theCENTERobject 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 doLayoutmethod.- Specified by:
- layoutContainerin interface- LayoutManager
- Parameters:
- target- the container in which to do the layout.
- See Also:
 
- 
toString
 
- 
addLayoutComponent(Component, Object).