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JavaTM 2 Platform Std. Ed. v1.3.1 |
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SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Object | +--java.awt.Component | +--java.awt.Container | +--javax.swing.JComponent | +--javax.swing.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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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.
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. A future release of Swing will provide support for long term persistence.
Inner Class Summary | |
protected class |
JLayeredPane.AccessibleJLayeredPane
This class implements accessibility support for the JLayeredPane class. |
Inner classes inherited from class javax.swing.JComponent |
JComponent.AccessibleJComponent |
Inner classes inherited from class java.awt.Container |
Container.AccessibleAWTContainer |
Inner classes inherited from class java.awt.Component |
Component.AccessibleAWTComponent |
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 |
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH |
Constructor Summary | |
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 |
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)
Primative 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 it's current layer (position -1). |
void |
moveToFront(Component c)
Moves the component to the top of the components in it's 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 |
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 it's current layer,
where 0 is the topmost position within the layer and -1 is the bottommost
position. |
Methods inherited from class java.awt.Container |
add, add, add, add, add, addContainerListener, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getLayout, insets, invalidate, isAncestorOf, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, removeAll, removeContainerListener, setLayout, validate, validateTree |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
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 |
public JLayeredPane()
Method Detail |
protected void addImpl(Component comp, Object constraints, int index)
Container
This is the method to override if a program needs to track every add request to a container. An overriding method should usually include a call to the superclass's version of the method:
super.addImpl(comp, constraints, index)
addImpl
in class Container
java.awt.Container
comp
- the component to be added.constraints
- an object expressing layout contraints
for this component.index
- the position in the container's list at which to
insert the component, where -1
means insert at the end.Container.add(java.awt.Component)
,
Container.add(java.awt.Component, int)
,
Container.add(java.awt.Component, java.lang.Object)
,
LayoutManager
public void remove(int index)
remove
in class Container
index
- an int specifying the component to removegetIndexOf(java.awt.Component)
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 checkpublic static JLayeredPane getLayeredPaneAbove(Component c)
c
- the Component to checkJFrame
,
JRootPane
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 it's 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 JComponent
g
- the Graphics context within which to paintprotected Hashtable 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 JComponent
public AccessibleContext getAccessibleContext()
getAccessibleContext
in interface Accessible
getAccessibleContext
in class JComponent
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JavaTM 2 Platform Std. Ed. v1.3.1 |
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