public class JLayeredPane extends JComponent implements Accessible
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, 1a
where 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, 1a
Calling add(5z, 5, 2) results in:
5a, 5b, 5z, 5c, 5x, 2a, 2b, 2c, 1a
Calling add(3a, 3, 7) results in:
5a, 5b, 5z, 5c, 5x, 3a, 2a, 2b, 2c, 1a
Using 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: Swing is not thread safe. For more information see Swing's Threading Policy.
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 JavaBeans™
has been added to the java.beans package.
Please see XMLEncoder.
| Modifier and Type | Class and Description |
|---|---|
protected class |
JLayeredPane.AccessibleJLayeredPane
This class implements accessibility support for the
JLayeredPane class. |
JComponent.AccessibleJComponentContainer.AccessibleAWTContainerComponent.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy| Modifier and Type | Field and Description |
|---|---|
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.
|
listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOWaccessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENTABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH| Constructor and Description |
|---|
JLayeredPane()
Create a new JLayeredPane
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| Modifier and Type | Method and Description |
|---|---|
protected void |
addImpl(Component comp,
Object constraints,
int index)
Adds the specified component to this container at the specified
index.
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AccessibleContext |
getAccessibleContext()
Gets the AccessibleContext associated with this JLayeredPane.
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int |
getComponentCountInLayer(int layer)
Returns the number of children currently in the specified layer.
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Component[] |
getComponentsInLayer(int layer)
Returns an array of the components in the specified layer.
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protected Hashtable<Component,Integer> |
getComponentToLayer()
Returns the hashtable that maps components to layers.
|
int |
getIndexOf(Component c)
Returns the index of the specified Component.
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int |
getLayer(Component c)
Returns the layer attribute for the specified Component.
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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.
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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.
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int |
highestLayer()
Returns the highest layer value from all current children.
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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.
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boolean |
isOptimizedDrawingEnabled()
Returns false if components in the pane can overlap, which makes
optimized drawing impossible.
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int |
lowestLayer()
Returns the lowest layer value from all current children.
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void |
moveToBack(Component c)
Moves the component to the bottom of the components in its current layer
(position -1).
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void |
moveToFront(Component c)
Moves the component to the top of the components in its current layer
(position 0).
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void |
paint(Graphics g)
Paints this JLayeredPane within the specified graphics context.
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protected String |
paramString()
Returns a string representation of this JLayeredPane.
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static void |
putLayer(JComponent c,
int layer)
Sets the layer property on a JComponent.
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void |
remove(int index)
Remove the indexed component from this pane.
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void |
removeAll()
Removes all the components from this container.
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void |
setLayer(Component c,
int layer)
Sets the layer attribute on the specified component,
making it the bottommost component in that layer.
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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. |
addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getUIClassID, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update, updateUIadd, add, add, add, add, addContainerListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusDownCycle, validate, validateTreeaction, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCyclepublic 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
JFramepublic static final String LAYER_PROPERTY
protected void addImpl(Component comp, Object constraints, int index)
ContaineraddLayoutComponent
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 current layout manager implements LayoutManager2, then
LayoutManager2.addLayoutComponent(Component,Object) is invoked on
it. If the current layout manager does not implement
LayoutManager2, and constraints is a String, then
LayoutManager.addLayoutComponent(String,Component) is invoked on it.
If the component is not an ancestor of this container and has a non-null parent, it is removed from its current parent before it is 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)
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
addImpl in class Containercomp - 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),
Container.invalidate(),
LayoutManager,
LayoutManager2public void remove(int index)
remove in class Containerindex - an int specifying the component to removegetIndexOf(java.awt.Component)public void removeAll()
removeAll in class ContainerContainer.add(java.awt.Component),
Container.remove(int),
Container.invalidate()public boolean isOptimizedDrawingEnabled()
isOptimizedDrawingEnabled in class JComponentJComponent.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 checkpublic 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 checkpublic int getIndexOf(Component c)
c - the Component to checkpublic 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 checkgetComponentCountInLayer(int)public int highestLayer()
public int lowestLayer()
public int getComponentCountInLayer(int layer)
layer - an int specifying the layer to checkpublic Component[] getComponentsInLayer(int layer)
layer - an int specifying the layer to checkpublic void paint(Graphics g)
paint in class JComponentg - 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 layerprotected int insertIndexForLayer(int layer,
int position)
layer - an int specifying the layerposition - an int specifying the position within the layergetIndexOf(java.awt.Component)protected String paramString()
null.paramString in class JComponentpublic AccessibleContext getAccessibleContext()
getAccessibleContext in interface AccessiblegetAccessibleContext in class Component Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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