Class JLayeredPane
- java.lang.Object
-
- java.awt.Component
-
- java.awt.Container
-
- javax.swing.JComponent
-
- javax.swing.JLayeredPane
- All Implemented Interfaces:
-
ImageObserver
,MenuContainer
,Serializable
,Accessible
- Direct Known Subclasses:
JDesktopPane
@JavaBean(defaultProperty="accessibleContext") 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.
|
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: - 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.
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. Details
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, Integer.valueOf.valueOf(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 use moveToFront, moveToBack, and setLayer.Here are some examples using the method add(Component, layer, position): Calling add(5x, 5, -1) results in:
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.beans
package. Please see XMLEncoder
.
- Since:
- 1.2
- See Also:
- Serialized Form
Nested Class Summary
Modifier and Type | Class | Description |
---|---|---|
protected class | JLayeredPane.AccessibleJLayeredPane | This class implements accessibility support for the |
Nested classes/interfaces declared in class javax.swing.JComponent
JComponent.AccessibleJComponent
Nested classes/interfaces declared in class java.awt.Container
Container.AccessibleAWTContainer
Nested classes/interfaces declared in class java.awt.Component
Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
Field Summary
Modifier and Type | Field | 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. |
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
Fields declared in class java.awt.Component
accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
Fields declared in interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
Constructor Summary
Constructor | Description |
---|---|
JLayeredPane() | Create a new JLayeredPane |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
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 |
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
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
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
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Field Detail
DEFAULT_LAYER
public static final Integer DEFAULT_LAYER
Convenience object defining the Default layer. Equivalent to Integer.valueOf(0).
PALETTE_LAYER
public static final Integer PALETTE_LAYER
Convenience object defining the Palette layer. Equivalent to Integer.valueOf(100).
MODAL_LAYER
public static final Integer MODAL_LAYER
Convenience object defining the Modal layer. Equivalent to Integer.valueOf(200).
POPUP_LAYER
public static final Integer POPUP_LAYER
Convenience object defining the Popup layer. Equivalent to Integer.valueOf(300).
DRAG_LAYER
public static final Integer DRAG_LAYER
Convenience object defining the Drag layer. Equivalent to Integer.valueOf(400).
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
LAYER_PROPERTY
public static final String LAYER_PROPERTY
Bound property
- See Also:
- Constant Field Values
Constructor Detail
JLayeredPane
public JLayeredPane()
Create a new JLayeredPane
Method Detail
remove
public void remove(int index)
Remove the indexed component from this pane. This is the absolute index, ignoring layers.
- Overrides:
-
remove
in classContainer
- Parameters:
-
index
- an int specifying the component to remove - See Also:
getIndexOf(java.awt.Component)
removeAll
public void removeAll()
Removes all the components from this container.
- Overrides:
-
removeAll
in classContainer
- Since:
- 1.5
- See Also:
-
Container.add(java.awt.Component)
,Container.remove(int)
,Container.invalidate()
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:
-
isOptimizedDrawingEnabled
in classJComponent
- Returns:
- false if components can overlap, else true
- See Also:
JComponent.isOptimizedDrawingEnabled()
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 move -
layer
- an int specifying the layer to move it to - See Also:
setLayer(java.awt.Component, int)
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
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.
- Parameters:
-
c
- the Component to check - Returns:
- the JLayeredPane that contains the component, or null if no JLayeredPane is found in the component hierarchy
- See Also:
-
JFrame
,JRootPane
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 for -
layer
- an int specifying the layer to set, where lower numbers are closer to the bottom
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 for -
layer
- an int specifying the layer to set, where lower numbers are closer to the bottom -
position
- an int specifying the position within the layer, where 0 is the topmost position and -1 is the bottommost position
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
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
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)
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)
setPosition
public 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.
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 move -
position
- an int in the range -1..N-1, where N is the number of components in the component's current layer
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)
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
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
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
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
paint
public void paint(Graphics g)
Paints this JLayeredPane within the specified graphics context.
- Overrides:
-
paint
in 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)
getComponentToLayer
protected Hashtable<Component,Integer> getComponentToLayer()
Returns the hashtable that maps components to layers.
- Returns:
- the Hashtable used to map components to their layers
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
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 layer -
position
- an int specifying the position within the layer - Returns:
- an int giving the (absolute) insertion-index
- See Also:
getIndexOf(java.awt.Component)
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 be null
.
- Overrides:
-
paramString
in classJComponent
- Returns:
- a string representation of this JLayeredPane.
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:
-
getAccessibleContext
in interfaceAccessible
- Overrides:
-
getAccessibleContext
in classComponent
- Returns:
- an AccessibleJLayeredPane that serves as the AccessibleContext of this JLayeredPane