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JavaTM 2 Platform Standard Ed. 5.0 |
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java.lang.Object java.awt.Component java.awt.Container javax.swing.JComponent javax.swing.JLayeredPane
public class JLayeredPane
JLayeredPane
adds depth to a JFC/Swing container,
allowing components to overlap each other when needed.
An Integer
object specifies each component's depth in the
container, where higher-numbered components sit "on top" of other
components.
For task-oriented documentation and examples of using layered panes see
How to Use a Layered Pane,
a section in The Java Tutorial.
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JLayeredPane
divides the depth-range
into several different layers. Putting a component into one of those
layers makes it easy to ensure that components overlap properly,
without having to worry about specifying numbers for specific depths:
JLayeredPane
methods moveToFront(Component)
,
moveToBack(Component)
and setPosition
can be used
to reposition a component within its layer. The setLayer
method
can also be used to change the component's current layer.
JLayeredPane
manages its list of children like
Container
, but allows for the definition of a several
layers within itself. Children in the same layer are managed exactly
like the normal Container
object,
with the added feature that when children components overlap, children
in higher layers display above the children in lower layers.
Each layer is a distinct integer number. The layer attribute can be set
on a Component
by passing an Integer
object during the add call.
For example:
layeredPane.add(child, JLayeredPane.DEFAULT_LAYER); or layeredPane.add(child, new Integer(10));The layer attribute can also be set on a Component by calling
layeredPaneParent.setLayer(child, 10)on the
JLayeredPane
that is the parent of component. The layer
should be set before adding the child to the parent.
Higher number layers display above lower number layers. So, using numbers for the layers and letters for individual components, a representative list order would look like this:
5a, 5b, 5c, 2a, 2b, 2c, 1awhere the leftmost components are closest to the top of the display.
A component can be moved to the top or bottom position within its
layer by calling moveToFront
or moveToBack
.
The position of a component within a layer can also be specified directly. Valid positions range from 0 up to one less than the number of components in that layer. A value of -1 indicates the bottommost position. A value of 0 indicates the topmost position. Unlike layer numbers, higher position values are lower in the display.
Note: This sequence (defined by java.awt.Container) is the reverse of the layer numbering sequence. Usually though, you will useHere are some examples using the method add(Component, layer, position): Calling add(5x, 5, -1) results in:moveToFront
,moveToBack
, andsetLayer
.
5a, 5b, 5c, 5x, 2a, 2b, 2c, 1aCalling add(5z, 5, 2) results in:
5a, 5b, 5z, 5c, 5x, 2a, 2b, 2c, 1aCalling add(3a, 3, 7) results in:
5a, 5b, 5z, 5c, 5x, 3a, 2a, 2b, 2c, 1aUsing normal paint/event mechanics results in 1a appearing at the bottom and 5a being above all other components.
Note: that these layers are simply a logical construct and LayoutManagers will affect all child components of this container without regard for layer settings.
Warning:
Serialized objects of this class will not be compatible with
future Swing releases. The current serialization support is
appropriate for short term storage or RMI between applications running
the same version of Swing. As of 1.4, support for long term storage
of all JavaBeansTM
has been added to the java.beans
package.
Please see XMLEncoder
.
Nested Class Summary | |
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protected class |
JLayeredPane.AccessibleJLayeredPane
This class implements accessibility support for the JLayeredPane class. |
Nested classes/interfaces inherited from class javax.swing.JComponent |
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JComponent.AccessibleJComponent |
Nested classes/interfaces inherited from class java.awt.Container |
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Container.AccessibleAWTContainer |
Nested classes/interfaces inherited from class java.awt.Component |
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Component.AccessibleAWTComponent, Component.BltBufferStrategy, Component.FlipBufferStrategy |
Field Summary | |
---|---|
static Integer |
DEFAULT_LAYER
Convenience object defining the Default layer. |
static Integer |
DRAG_LAYER
Convenience object defining the Drag layer. |
static Integer |
FRAME_CONTENT_LAYER
Convenience object defining the Frame Content layer. |
static String |
LAYER_PROPERTY
Bound property |
static Integer |
MODAL_LAYER
Convenience object defining the Modal layer. |
static Integer |
PALETTE_LAYER
Convenience object defining the Palette layer. |
static Integer |
POPUP_LAYER
Convenience object defining the Popup layer. |
Fields inherited from class javax.swing.JComponent |
---|
accessibleContext, listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW |
Fields inherited from class java.awt.Component |
---|
BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT |
Fields inherited from interface java.awt.image.ImageObserver |
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ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH |
Constructor Summary | |
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JLayeredPane()
Create a new JLayeredPane |
Method Summary | |
---|---|
protected void |
addImpl(Component comp,
Object constraints,
int index)
Adds the specified component to this container at the specified index. |
AccessibleContext |
getAccessibleContext()
Gets the AccessibleContext associated with this JLayeredPane. |
int |
getComponentCountInLayer(int layer)
Returns the number of children currently in the specified layer. |
Component[] |
getComponentsInLayer(int layer)
Returns an array of the components in the specified layer. |
protected Hashtable<Component,Integer> |
getComponentToLayer()
Returns the hashtable that maps components to layers. |
int |
getIndexOf(Component c)
Returns the index of the specified Component. |
int |
getLayer(Component c)
Returns the layer attribute for the specified Component. |
static int |
getLayer(JComponent c)
Gets the layer property for a JComponent, it does not cause any side effects like setLayer(). |
static JLayeredPane |
getLayeredPaneAbove(Component c)
Convenience method that returns the first JLayeredPane which contains the specified component. |
protected Integer |
getObjectForLayer(int layer)
Returns the Integer object associated with a specified layer. |
int |
getPosition(Component c)
Get the relative position of the component within its layer. |
int |
highestLayer()
Returns the highest layer value from all current children. |
protected int |
insertIndexForLayer(int layer,
int position)
Primitive method that determines the proper location to insert a new child based on layer and position requests. |
boolean |
isOptimizedDrawingEnabled()
Returns false if components in the pane can overlap, which makes optimized drawing impossible. |
int |
lowestLayer()
Returns the lowest layer value from all current children. |
void |
moveToBack(Component c)
Moves the component to the bottom of the components in its current layer (position -1). |
void |
moveToFront(Component c)
Moves the component to the top of the components in its current layer (position 0). |
void |
paint(Graphics g)
Paints this JLayeredPane within the specified graphics context. |
protected String |
paramString()
Returns a string representation of this JLayeredPane. |
static void |
putLayer(JComponent c,
int layer)
Sets the layer property on a JComponent. |
void |
remove(int index)
Remove the indexed component from this pane. |
void |
removeAll()
Removes all the components from this container. |
void |
setLayer(Component c,
int layer)
Sets the layer attribute on the specified component, making it the bottommost component in that layer. |
void |
setLayer(Component c,
int layer,
int position)
Sets the layer attribute for the specified component and also sets its position within that layer. |
void |
setPosition(Component c,
int position)
Moves the component to position within its current layer,
where 0 is the topmost position within the layer and -1 is the bottommost
position. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
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public static final Integer DEFAULT_LAYER
public static final Integer PALETTE_LAYER
public static final Integer MODAL_LAYER
public static final Integer POPUP_LAYER
public static final Integer DRAG_LAYER
public static final Integer FRAME_CONTENT_LAYER
JFrame
public static final String LAYER_PROPERTY
Constructor Detail |
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public JLayeredPane()
Method Detail |
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protected void addImpl(Component comp, Object constraints, int index)
Container
addLayoutComponent
method.
The constraints are
defined by the particular layout manager being used. For
example, the BorderLayout
class defines five
constraints: BorderLayout.NORTH
,
BorderLayout.SOUTH
, BorderLayout.EAST
,
BorderLayout.WEST
, and BorderLayout.CENTER
.
The GridBagLayout
class requires a
GridBagConstraints
object. Failure to pass
the correct type of constraints object results in an
IllegalArgumentException
.
If the layout manager implements both the LayoutManager
and LayoutManager2
interfaces, the
LayoutManager2
methods are called.
Note that if the component already exists in this container or a child of this container, it is removed from that container before being added to this container.
This is the method to override if a program needs to track every add request to a container as all other add methods defer to this one. An overriding method should usually include a call to the superclass's version of the method:
super.addImpl(comp, constraints, index)
comp
- the component to be addedconstraints
- an object expressing layout constraints
for this componentindex
- the position in the container's list at which to
insert the component, where -1
means append to the endContainer.add(Component)
,
Container.add(Component, int)
,
Container.add(Component, java.lang.Object)
,
LayoutManager
,
LayoutManager2
public void remove(int index)
index
- an int specifying the component to removegetIndexOf(java.awt.Component)
public void removeAll()
Container.add(java.awt.Component)
,
Container.remove(int)
public boolean isOptimizedDrawingEnabled()
isOptimizedDrawingEnabled
in class JComponent
JComponent.isOptimizedDrawingEnabled()
public static void putLayer(JComponent c, int layer)
c
- the JComponent to movelayer
- an int specifying the layer to move it tosetLayer(java.awt.Component, int)
public static int getLayer(JComponent c)
c
- the JComponent to check
public static JLayeredPane getLayeredPaneAbove(Component c)
public void setLayer(Component c, int layer)
c
- the Component to set the layer forlayer
- an int specifying the layer to set, where
lower numbers are closer to the bottompublic void setLayer(Component c, int layer, int position)
c
- the Component to set the layer forlayer
- an int specifying the layer to set, where
lower numbers are closer to the bottomposition
- an int specifying the position within the
layer, where 0 is the topmost position and -1
is the bottommost positionpublic int getLayer(Component c)
c
- the Component to check
public int getIndexOf(Component c)
c
- the Component to check
public void moveToFront(Component c)
c
- the Component to movesetPosition(Component, int)
public void moveToBack(Component c)
c
- the Component to movesetPosition(Component, int)
public void setPosition(Component c, int position)
position
within its current layer,
where 0 is the topmost position within the layer and -1 is the bottommost
position.
Note: Position numbering is defined by java.awt.Container, and is the opposite of layer numbering. Lower position numbers are closer to the top (0 is topmost), and higher position numbers are closer to the bottom.
c
- the Component to moveposition
- an int in the range -1..N-1, where N is the number of
components in the component's current layerpublic int getPosition(Component c)
c
- the Component to check
getComponentCountInLayer(int)
public int highestLayer()
public int lowestLayer()
public int getComponentCountInLayer(int layer)
layer
- an int specifying the layer to check
public Component[] getComponentsInLayer(int layer)
layer
- an int specifying the layer to check
public void paint(Graphics g)
paint
in class JComponent
g
- the Graphics context within which to paintJComponent.paintComponent(java.awt.Graphics)
,
JComponent.paintBorder(java.awt.Graphics)
,
JComponent.paintChildren(java.awt.Graphics)
,
JComponent.getComponentGraphics(java.awt.Graphics)
,
JComponent.repaint(long, int, int, int, int)
protected Hashtable<Component,Integer> getComponentToLayer()
protected Integer getObjectForLayer(int layer)
layer
- an int specifying the layer
protected int insertIndexForLayer(int layer, int position)
layer
- an int specifying the layerposition
- an int specifying the position within the layer
getIndexOf(java.awt.Component)
protected String paramString()
null
.
paramString
in class JComponent
public AccessibleContext getAccessibleContext()
getAccessibleContext
in interface Accessible
getAccessibleContext
in class JComponent
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JavaTM 2 Platform Standard Ed. 5.0 |
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Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.