- java.lang.Object
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- java.awt.Component
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- java.awt.Container
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- javax.swing.JComponent
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- javax.swing.JLayeredPane
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- All Implemented Interfaces:
ImageObserver,MenuContainer,Serializable,Accessible
- Direct Known Subclasses:
JDesktopPane
@JavaBean(defaultProperty="accessibleContext") public class JLayeredPane extends JComponent implements Accessible
JLayeredPaneadds depth to a JFC/Swing container, allowing components to overlap each other when needed. AnIntegerobject 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.
For convenience,Example
JLayeredPanedivides 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:- DEFAULT_LAYER
- The standard layer, where most components go. This the bottommost layer.
- PALETTE_LAYER
- The palette layer sits over the default layer. Useful for floating toolbars and palettes, so they can be positioned above other components.
- MODAL_LAYER
- The layer used for modal dialogs. They will appear on top of any toolbars, palettes, or standard components in the container.
- POPUP_LAYER
- The popup layer displays above dialogs. That way, the popup windows associated with combo boxes, tooltips, and other help text will appear above the component, palette, or dialog that generated them.
- DRAG_LAYER
- When dragging a component, reassigning it to the drag layer ensures that it is positioned over every other component in the container. When finished dragging, it can be reassigned to its normal layer.
JLayeredPanemethodsmoveToFront(Component),moveToBack(Component)andsetPositioncan be used to reposition a component within its layer. ThesetLayermethod can also be used to change the component's current layer.Details
JLayeredPanemanages its list of children likeContainer, but allows for the definition of a several layers within itself. Children in the same layer are managed exactly like the normalContainerobject, 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
Componentby passing anIntegerobject during the add call.
For example:layeredPane.add(child, JLayeredPane.DEFAULT_LAYER); or layeredPane.add(child, Integer.valueOf.valueOf(10));The layer attribute can also be set on a Component by callinglayeredPaneParent.setLayer(child, 10)on theJLayeredPanethat 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
moveToFrontormoveToBack.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 use
Here 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: 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.beanspackage. Please seeXMLEncoder.- Since:
- 1.2
- See Also:
- Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class Description protected classJLayeredPane.AccessibleJLayeredPaneThis class implements accessibility support for theJLayeredPaneclass.-
Nested classes/interfaces declared in class javax.swing.JComponent
JComponent.AccessibleJComponent
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Nested classes/interfaces declared in class java.awt.Container
Container.AccessibleAWTContainer
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Nested classes/interfaces declared in class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
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Field Summary
Fields Modifier and Type Field Description static IntegerDEFAULT_LAYERConvenience object defining the Default layer.static IntegerDRAG_LAYERConvenience object defining the Drag layer.static IntegerFRAME_CONTENT_LAYERConvenience object defining the Frame Content layer.static StringLAYER_PROPERTYBound propertystatic IntegerMODAL_LAYERConvenience object defining the Modal layer.static IntegerPALETTE_LAYERConvenience object defining the Palette layer.static IntegerPOPUP_LAYERConvenience object defining the Popup layer.-
Fields declared in class javax.swing.JComponent
listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW
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Fields declared in class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
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Fields declared in interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
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Constructor Summary
Constructors Constructor Description JLayeredPane()Create a new JLayeredPane
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description AccessibleContextgetAccessibleContext()Gets the AccessibleContext associated with this JLayeredPane.intgetComponentCountInLayer(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.intgetIndexOf(Component c)Returns the index of the specified Component.intgetLayer(Component c)Returns the layer attribute for the specified Component.static intgetLayer(JComponent c)Gets the layer property for a JComponent, it does not cause any side effects like setLayer().static JLayeredPanegetLayeredPaneAbove(Component c)Convenience method that returns the first JLayeredPane which contains the specified component.protected IntegergetObjectForLayer(int layer)Returns the Integer object associated with a specified layer.intgetPosition(Component c)Get the relative position of the component within its layer.inthighestLayer()Returns the highest layer value from all current children.protected intinsertIndexForLayer(int layer, int position)Primitive method that determines the proper location to insert a new child based on layer and position requests.booleanisOptimizedDrawingEnabled()Returns false if components in the pane can overlap, which makes optimized drawing impossible.intlowestLayer()Returns the lowest layer value from all current children.voidmoveToBack(Component c)Moves the component to the bottom of the components in its current layer (position -1).voidmoveToFront(Component c)Moves the component to the top of the components in its current layer (position 0).voidpaint(Graphics g)Paints this JLayeredPane within the specified graphics context.protected StringparamString()Returns a string representation of this JLayeredPane.static voidputLayer(JComponent c, int layer)Sets the layer property on a JComponent.voidremove(int index)Remove the indexed component from this pane.voidremoveAll()Removes all the components from this container.voidsetLayer(Component c, int layer)Sets the layer attribute on the specified component, making it the bottommost component in that layer.voidsetLayer(Component c, int layer, int position)Sets the layer attribute for the specified component and also sets its position within that layer.voidsetPosition(Component c, int position)Moves the component topositionwithin its current layer, where 0 is the topmost position within the layer and -1 is the bottommost position.-
Methods declared in class javax.swing.JComponent
addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, 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, getUI, getUIClassID, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, 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, updateUI
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Methods declared in class java.awt.Container
add, add, add, add, add, addContainerListener, addImpl, 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, validateTree
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Methods declared in class java.awt.Component
action, 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, 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, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, hide, 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, requestFocus, requestFocus, requestFocusInWindow, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setMixingCutoutShape, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle
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Field Detail
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DEFAULT_LAYER
public static final Integer DEFAULT_LAYER
Convenience object defining the Default layer. Equivalent to Integer.valueOf(0).
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PALETTE_LAYER
public static final Integer PALETTE_LAYER
Convenience object defining the Palette layer. Equivalent to Integer.valueOf(100).
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MODAL_LAYER
public static final Integer MODAL_LAYER
Convenience object defining the Modal layer. Equivalent to Integer.valueOf(200).
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POPUP_LAYER
public static final Integer POPUP_LAYER
Convenience object defining the Popup layer. Equivalent to Integer.valueOf(300).
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DRAG_LAYER
public static final Integer DRAG_LAYER
Convenience object defining the Drag layer. Equivalent to Integer.valueOf(400).
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FRAME_CONTENT_LAYER
public static final Integer FRAME_CONTENT_LAYER
Convenience object defining the Frame Content layer. This layer is normally only use to position the contentPane and menuBar components of JFrame. Equivalent to Integer.valueOf(-30000).- See Also:
JFrame
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LAYER_PROPERTY
public static final String LAYER_PROPERTY
Bound property- See Also:
- Constant Field Values
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Method Detail
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remove
public void remove(int index)
Remove the indexed component from this pane. This is the absolute index, ignoring layers.- Overrides:
removein classContainer- Parameters:
index- an int specifying the component to remove- See Also:
getIndexOf(java.awt.Component)
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removeAll
public void removeAll()
Removes all the components from this container.- Overrides:
removeAllin classContainer- Since:
- 1.5
- See Also:
Container.add(java.awt.Component),Container.remove(int),Container.invalidate()
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isOptimizedDrawingEnabled
@BeanProperty(bound=false) public boolean isOptimizedDrawingEnabled()
Returns false if components in the pane can overlap, which makes optimized drawing impossible. Otherwise, returns true.- Overrides:
isOptimizedDrawingEnabledin classJComponent- Returns:
- false if components can overlap, else true
- See Also:
JComponent.isOptimizedDrawingEnabled()
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putLayer
public static void putLayer(JComponent c, int layer)
Sets the layer property on a JComponent. This method does not cause any side effects like setLayer() (painting, add/remove, etc). Normally you should use the instance method setLayer(), in order to get the desired side-effects (like repainting).- Parameters:
c- the JComponent to movelayer- an int specifying the layer to move it to- See Also:
setLayer(java.awt.Component, int)
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getLayer
public static int getLayer(JComponent c)
Gets the layer property for a JComponent, it does not cause any side effects like setLayer(). (painting, add/remove, etc) Normally you should use the instance method getLayer().- Parameters:
c- the JComponent to check- Returns:
- an int specifying the component's layer
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getLayeredPaneAbove
public static JLayeredPane getLayeredPaneAbove(Component c)
Convenience method that returns the first JLayeredPane which contains the specified component. Note that all JFrames have a JLayeredPane at their root, so any component in a JFrame will have a JLayeredPane parent.
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setLayer
public void setLayer(Component c, int layer)
Sets the layer attribute on the specified component, making it the bottommost component in that layer. Should be called before adding to parent.- Parameters:
c- the Component to set the layer forlayer- an int specifying the layer to set, where lower numbers are closer to the bottom
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setLayer
public void setLayer(Component c, int layer, int position)
Sets the layer attribute for the specified component and also sets its position within that layer.- Parameters:
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 position
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getLayer
public int getLayer(Component c)
Returns the layer attribute for the specified Component.- Parameters:
c- the Component to check- Returns:
- an int specifying the component's current layer
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getIndexOf
public int getIndexOf(Component c)
Returns the index of the specified Component. This is the absolute index, ignoring layers. Index numbers, like position numbers, have the topmost component at index zero. Larger numbers are closer to the bottom.- Parameters:
c- the Component to check- Returns:
- an int specifying the component's index
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moveToFront
public void moveToFront(Component c)
Moves the component to the top of the components in its current layer (position 0).- Parameters:
c- the Component to move- See Also:
setPosition(Component, int)
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moveToBack
public void moveToBack(Component c)
Moves the component to the bottom of the components in its current layer (position -1).- Parameters:
c- the Component to move- See Also:
setPosition(Component, int)
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setPosition
public void setPosition(Component c, int position)
Moves the component topositionwithin 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.
- Parameters:
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 layer
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getPosition
public int getPosition(Component c)
Get the relative position of the component within its layer.- Parameters:
c- the Component to check- Returns:
- an int giving the component's position, where 0 is the topmost position and the highest index value = the count count of components at that layer, minus 1
- See Also:
getComponentCountInLayer(int)
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highestLayer
public int highestLayer()
Returns the highest layer value from all current children. Returns 0 if there are no children.- Returns:
- an int indicating the layer of the topmost component in the pane, or zero if there are no children
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lowestLayer
public int lowestLayer()
Returns the lowest layer value from all current children. Returns 0 if there are no children.- Returns:
- an int indicating the layer of the bottommost component in the pane, or zero if there are no children
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getComponentCountInLayer
public int getComponentCountInLayer(int layer)
Returns the number of children currently in the specified layer.- Parameters:
layer- an int specifying the layer to check- Returns:
- an int specifying the number of components in that layer
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getComponentsInLayer
public Component[] getComponentsInLayer(int layer)
Returns an array of the components in the specified layer.- Parameters:
layer- an int specifying the layer to check- Returns:
- an array of Components contained in that layer
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paint
public void paint(Graphics g)
Paints this JLayeredPane within the specified graphics context.- Overrides:
paintin classJComponent- Parameters:
g- the Graphics context within which to paint- See Also:
JComponent.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)
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getComponentToLayer
protected Hashtable<Component,Integer> getComponentToLayer()
Returns the hashtable that maps components to layers.- Returns:
- the Hashtable used to map components to their layers
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getObjectForLayer
protected Integer getObjectForLayer(int layer)
Returns the Integer object associated with a specified layer.- Parameters:
layer- an int specifying the layer- Returns:
- an Integer object for that layer
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insertIndexForLayer
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.- Parameters:
layer- an int specifying the layerposition- an int specifying the position within the layer- Returns:
- an int giving the (absolute) insertion-index
- See Also:
getIndexOf(java.awt.Component)
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paramString
protected String paramString()
Returns a string representation of this JLayeredPane. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not benull.- Overrides:
paramStringin classJComponent- Returns:
- a string representation of this JLayeredPane.
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getAccessibleContext
@BeanProperty(bound=false) public AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this JLayeredPane. For layered panes, the AccessibleContext takes the form of an AccessibleJLayeredPane. A new AccessibleJLayeredPane instance is created if necessary.- Specified by:
getAccessibleContextin interfaceAccessible- Overrides:
getAccessibleContextin classComponent- Returns:
- an AccessibleJLayeredPane that serves as the AccessibleContext of this JLayeredPane
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