JDK8/Java8源码在线阅读
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* accompanied this code).
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package javax.swing;
import java.awt.Component;
import java.util.ArrayList;
import java.util.Hashtable;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import sun.awt.SunToolkit;
import javax.accessibility.*;
/**
* <code>JLayeredPane</code> adds depth to a JFC/Swing container,
* allowing components to overlap each other when needed.
* An <code>Integer</code> 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
* <a href="https://docs.oracle.com/javase/tutorial/uiswing/components/layeredpane.html">How to Use a Layered Pane</a>,
* a section in <em>The Java Tutorial</em>.
*
* <TABLE STYLE="FLOAT:RIGHT" BORDER="0" SUMMARY="layout">
* <TR>
* <TD ALIGN="CENTER">
* <P STYLE="TEXT-ALIGN:CENTER"><IMG SRC="doc-files/JLayeredPane-1.gif"
* alt="The following text describes this image."
* WIDTH="269" HEIGHT="264" STYLE="FLOAT:BOTTOM; BORDER=0">
* </TD>
* </TR>
* </TABLE>
* For convenience, <code>JLayeredPane</code> 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:
* <DL>
* <DT><FONT SIZE="2">DEFAULT_LAYER</FONT></DT>
* <DD>The standard layer, where most components go. This the bottommost
* layer.
* <DT><FONT SIZE="2">PALETTE_LAYER</FONT></DT>
* <DD>The palette layer sits over the default layer. Useful for floating
* toolbars and palettes, so they can be positioned above other components.
* <DT><FONT SIZE="2">MODAL_LAYER</FONT></DT>
* <DD>The layer used for modal dialogs. They will appear on top of any
* toolbars, palettes, or standard components in the container.
* <DT><FONT SIZE="2">POPUP_LAYER</FONT></DT>
* <DD>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.
* <DT><FONT SIZE="2">DRAG_LAYER</FONT></DT>
* <DD>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.
* </DL>
* The <code>JLayeredPane</code> methods <code>moveToFront(Component)</code>,
* <code>moveToBack(Component)</code> and <code>setPosition</code> can be used
* to reposition a component within its layer. The <code>setLayer</code> method
* can also be used to change the component's current layer.
*
* <h2>Details</h2>
* <code>JLayeredPane</code> manages its list of children like
* <code>Container</code>, but allows for the definition of a several
* layers within itself. Children in the same layer are managed exactly
* like the normal <code>Container</code> object,
* with the added feature that when children components overlap, children
* in higher layers display above the children in lower layers.
* <p>
* Each layer is a distinct integer number. The layer attribute can be set
* on a <code>Component</code> by passing an <code>Integer</code>
* object during the add call.<br> For example:
* <PRE>
* layeredPane.add(child, JLayeredPane.DEFAULT_LAYER);
* or
* layeredPane.add(child, new Integer(10));
* </PRE>
* The layer attribute can also be set on a Component by calling<PRE>
* layeredPaneParent.setLayer(child, 10)</PRE>
* on the <code>JLayeredPane</code> that is the parent of component. The layer
* should be set <i>before</i> adding the child to the parent.
* <p>
* 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:<PRE>
* 5a, 5b, 5c, 2a, 2b, 2c, 1a </PRE>
* where the leftmost components are closest to the top of the display.
* <p>
* A component can be moved to the top or bottom position within its
* layer by calling <code>moveToFront</code> or <code>moveToBack</code>.
* <p>
* 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 <i>lower</i> in the display.
* <blockquote>
* <b>Note:</b> This sequence (defined by java.awt.Container) is the reverse
* of the layer numbering sequence. Usually though, you will use <code>moveToFront</code>,
* <code>moveToBack</code>, and <code>setLayer</code>.
* </blockquote>
* Here are some examples using the method add(Component, layer, position):
* Calling add(5x, 5, -1) results in:<PRE>
* 5a, 5b, 5c, 5x, 2a, 2b, 2c, 1a </PRE>
*
* Calling add(5z, 5, 2) results in:<PRE>
* 5a, 5b, 5z, 5c, 5x, 2a, 2b, 2c, 1a </PRE>
*
* Calling add(3a, 3, 7) results in:<PRE>
* 5a, 5b, 5z, 5c, 5x, 3a, 2a, 2b, 2c, 1a </PRE>
*
* Using normal paint/event mechanics results in 1a appearing at the bottom
* and 5a being above all other components.
* <p>
* <b>Note:</b> that these layers are simply a logical construct and LayoutManagers
* will affect all child components of this container without regard for
* layer settings.
* <p>
* <strong>Warning:</strong> Swing is not thread safe. For more
* information see <a
* href="package-summary.html#threading">Swing's Threading
* Policy</a>.
* <p>
* <strong>Warning:</strong>
* 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 <code>java.beans</code> package.
* Please see {@link java.beans.XMLEncoder}.
*
* @author David Kloba
*/
@SuppressWarnings("serial")
public class JLayeredPane extends JComponent implements Accessible {
/// Watch the values in getObjectForLayer()
/** Convenience object defining the Default layer. Equivalent to new Integer(0).*/
public final static Integer DEFAULT_LAYER = new Integer(0);
/** Convenience object defining the Palette layer. Equivalent to new Integer(100).*/
public final static Integer PALETTE_LAYER = new Integer(100);
/** Convenience object defining the Modal layer. Equivalent to new Integer(200).*/
public final static Integer MODAL_LAYER = new Integer(200);
/** Convenience object defining the Popup layer. Equivalent to new Integer(300).*/
public final static Integer POPUP_LAYER = new Integer(300);
/** Convenience object defining the Drag layer. Equivalent to new Integer(400).*/
public final static Integer DRAG_LAYER = new Integer(400);
/** Convenience object defining the Frame Content layer.
* This layer is normally only use to position the contentPane and menuBar
* components of JFrame.
* Equivalent to new Integer(-30000).
* @see JFrame
*/
public final static Integer FRAME_CONTENT_LAYER = new Integer(-30000);
/** Bound property */
public final static String LAYER_PROPERTY = "layeredContainerLayer";
// Hashtable to store layer values for non-JComponent components
private Hashtable<Component,Integer> componentToLayer;
private boolean optimizedDrawingPossible = true;
//////////////////////////////////////////////////////////////////////////////
//// Container Override methods
//////////////////////////////////////////////////////////////////////////////
/** Create a new JLayeredPane */
public JLayeredPane() {
setLayout(null);
}
private void validateOptimizedDrawing() {
boolean layeredComponentFound = false;
synchronized(getTreeLock()) {
Integer layer;
for (Component c : getComponents()) {
layer = null;
if(SunToolkit.isInstanceOf(c, "javax.swing.JInternalFrame") ||
(c instanceof JComponent &&
(layer = (Integer)((JComponent)c).
getClientProperty(LAYER_PROPERTY)) != null))
{
if(layer != null && layer.equals(FRAME_CONTENT_LAYER))
continue;
layeredComponentFound = true;
break;
}
}
}
if(layeredComponentFound)
optimizedDrawingPossible = false;
else
optimizedDrawingPossible = true;
}
protected void addImpl(Component comp, Object constraints, int index) {
int layer;
int pos;
if(constraints instanceof Integer) {
layer = ((Integer)constraints).intValue();
setLayer(comp, layer);
} else
layer = getLayer(comp);
pos = insertIndexForLayer(layer, index);
super.addImpl(comp, constraints, pos);
comp.validate();
comp.repaint();
validateOptimizedDrawing();
}
/**
* Remove the indexed component from this pane.
* This is the absolute index, ignoring layers.
*
* @param index an int specifying the component to remove
* @see #getIndexOf
*/
public void remove(int index) {
Component c = getComponent(index);
super.remove(index);
if (c != null && !(c instanceof JComponent)) {
getComponentToLayer().remove(c);
}
validateOptimizedDrawing();
}
/**
* Removes all the components from this container.
*
* @since 1.5
*/
public void removeAll() {
Component[] children = getComponents();
Hashtable<Component, Integer> cToL = getComponentToLayer();
for (int counter = children.length - 1; counter >= 0; counter--) {
Component c = children[counter];
if (c != null && !(c instanceof JComponent)) {
cToL.remove(c);
}
}
super.removeAll();
}
/**
* Returns false if components in the pane can overlap, which makes
* optimized drawing impossible. Otherwise, returns true.
*
* @return false if components can overlap, else true
* @see JComponent#isOptimizedDrawingEnabled
*/
public boolean isOptimizedDrawingEnabled() {
return optimizedDrawingPossible;
}
//////////////////////////////////////////////////////////////////////////////
//// New methods for managing layers
//////////////////////////////////////////////////////////////////////////////
/** 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).
*
* @param c the JComponent to move
* @param layer an int specifying the layer to move it to
* @see #setLayer
*/
public static void putLayer(JComponent c, int layer) {
/// MAKE SURE THIS AND setLayer(Component c, int layer, int position) are SYNCED
Integer layerObj;
layerObj = new Integer(layer);
c.putClientProperty(LAYER_PROPERTY, layerObj);
}
/** 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().
*
* @param c the JComponent to check
* @return an int specifying the component's layer
*/
public static int getLayer(JComponent c) {
Integer i;
if((i = (Integer)c.getClientProperty(LAYER_PROPERTY)) != null)
return i.intValue();
return DEFAULT_LAYER.intValue();
}
/** 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.
*
* @param c the Component to check
* @return the JLayeredPane that contains the component, or
* null if no JLayeredPane is found in the component
* hierarchy
* @see JFrame
* @see JRootPane
*/
public static JLayeredPane getLayeredPaneAbove(Component c) {
if(c == null) return null;
Component parent = c.getParent();
while(parent != null && !(parent instanceof JLayeredPane))
parent = parent.getParent();
return (JLayeredPane)parent;
}
/** Sets the layer attribute on the specified component,
* making it the bottommost component in that layer.
* Should be called before adding to parent.
*
* @param c the Component to set the layer for
* @param layer an int specifying the layer to set, where
* lower numbers are closer to the bottom
*/
public void setLayer(Component c, int layer) {
setLayer(c, layer, -1);
}
/** Sets the layer attribute for the specified component and
* also sets its position within that layer.
*
* @param c the Component to set the layer for
* @param layer an int specifying the layer to set, where
* lower numbers are closer to the bottom
* @param position an int specifying the position within the
* layer, where 0 is the topmost position and -1
* is the bottommost position
*/
public void setLayer(Component c, int layer, int position) {
Integer layerObj;
layerObj = getObjectForLayer(layer);
if(layer == getLayer(c) && position == getPosition(c)) {
repaint(c.getBounds());
return;
}
/// MAKE SURE THIS AND putLayer(JComponent c, int layer) are SYNCED
if(c instanceof JComponent)
((JComponent)c).putClientProperty(LAYER_PROPERTY, layerObj);
else
getComponentToLayer().put(c, layerObj);
if(c.getParent() == null || c.getParent() != this) {
repaint(c.getBounds());
return;
}
int index = insertIndexForLayer(c, layer, position);
setComponentZOrder(c, index);
repaint(c.getBounds());
}
/**
* Returns the layer attribute for the specified Component.
*
* @param c the Component to check
* @return an int specifying the component's current layer
*/
public int getLayer(Component c) {
Integer i;
if(c instanceof JComponent)
i = (Integer)((JComponent)c).getClientProperty(LAYER_PROPERTY);
else
i = getComponentToLayer().get(c);
if(i == null)
return DEFAULT_LAYER.intValue();
return i.intValue();
}
/**
* 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.
*
* @param c the Component to check
* @return an int specifying the component's index
*/
public int getIndexOf(Component c) {
int i, count;
count = getComponentCount();
for(i = 0; i < count; i++) {
if(c == getComponent(i))
return i;
}
return -1;
}
/**
* Moves the component to the top of the components in its current layer
* (position 0).
*
* @param c the Component to move
* @see #setPosition(Component, int)
*/
public void moveToFront(Component c) {
setPosition(c, 0);
}
/**
* Moves the component to the bottom of the components in its current layer
* (position -1).
*
* @param c the Component to move
* @see #setPosition(Component, int)
*/
public void moveToBack(Component c) {
setPosition(c, -1);
}
/**
* Moves the component to <code>position</code> within its current layer,
* where 0 is the topmost position within the layer and -1 is the bottommost
* position.
* <p>
* <b>Note:</b> 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.
*
* @param c the Component to move
* @param position an int in the range -1..N-1, where N is the number of
* components in the component's current layer
*/
public void setPosition(Component c, int position) {
setLayer(c, getLayer(c), position);
}
/**
* Get the relative position of the component within its layer.
*
* @param c the Component to check
* @return 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 #getComponentCountInLayer
*/
public int getPosition(Component c) {
int i, startLayer, curLayer, startLocation, pos = 0;
getComponentCount();
startLocation = getIndexOf(c);
if(startLocation == -1)
return -1;
startLayer = getLayer(c);
for(i = startLocation - 1; i >= 0; i--) {
curLayer = getLayer(getComponent(i));
if(curLayer == startLayer)
pos++;
else
return pos;
}
return pos;
}
/** Returns the highest layer value from all current children.
* Returns 0 if there are no children.
*
* @return an int indicating the layer of the topmost component in the
* pane, or zero if there are no children
*/
public int highestLayer() {
if(getComponentCount() > 0)
return getLayer(getComponent(0));
return 0;
}
/** Returns the lowest layer value from all current children.
* Returns 0 if there are no children.
*
* @return an int indicating the layer of the bottommost component in the
* pane, or zero if there are no children
*/
public int lowestLayer() {
int count = getComponentCount();
if(count > 0)
return getLayer(getComponent(count-1));
return 0;
}
/**
* Returns the number of children currently in the specified layer.
*
* @param layer an int specifying the layer to check
* @return an int specifying the number of components in that layer
*/
public int getComponentCountInLayer(int layer) {
int i, count, curLayer;
int layerCount = 0;
count = getComponentCount();
for(i = 0; i < count; i++) {
curLayer = getLayer(getComponent(i));
if(curLayer == layer) {
layerCount++;
/// Short circut the counting when we have them all
} else if(layerCount > 0 || curLayer < layer) {
break;
}
}
return layerCount;
}
/**
* Returns an array of the components in the specified layer.
*
* @param layer an int specifying the layer to check
* @return an array of Components contained in that layer
*/
public Component[] getComponentsInLayer(int layer) {
int i, count, curLayer;
int layerCount = 0;
Component[] results;
results = new Component[getComponentCountInLayer(layer)];
count = getComponentCount();
for(i = 0; i < count; i++) {
curLayer = getLayer(getComponent(i));
if(curLayer == layer) {
results[layerCount++] = getComponent(i);
/// Short circut the counting when we have them all
} else if(layerCount > 0 || curLayer < layer) {
break;
}
}
return results;
}
/**
* Paints this JLayeredPane within the specified graphics context.
*
* @param g the Graphics context within which to paint
*/
public void paint(Graphics g) {
if(isOpaque()) {
Rectangle r = g.getClipBounds();
Color c = getBackground();
if(c == null)
c = Color.lightGray;
g.setColor(c);
if (r != null) {
g.fillRect(r.x, r.y, r.width, r.height);
}
else {
g.fillRect(0, 0, getWidth(), getHeight());
}
}
super.paint(g);
}
//////////////////////////////////////////////////////////////////////////////
//// Implementation Details
//////////////////////////////////////////////////////////////////////////////
/**
* Returns the hashtable that maps components to layers.
*
* @return the Hashtable used to map components to their layers
*/
protected Hashtable<Component,Integer> getComponentToLayer() {
if(componentToLayer == null)
componentToLayer = new Hashtable<Component,Integer>(4);
return componentToLayer;
}
/**
* Returns the Integer object associated with a specified layer.
*
* @param layer an int specifying the layer
* @return an Integer object for that layer
*/
protected Integer getObjectForLayer(int layer) {
Integer layerObj;
switch(layer) {
case 0:
layerObj = DEFAULT_LAYER;
break;
case 100:
layerObj = PALETTE_LAYER;
break;
case 200:
layerObj = MODAL_LAYER;
break;
case 300:
layerObj = POPUP_LAYER;
break;
case 400:
layerObj = DRAG_LAYER;
break;
default:
layerObj = new Integer(layer);
}
return layerObj;
}
/**
* Primitive method that determines the proper location to
* insert a new child based on layer and position requests.
*
* @param layer an int specifying the layer
* @param position an int specifying the position within the layer
* @return an int giving the (absolute) insertion-index
*
* @see #getIndexOf
*/
protected int insertIndexForLayer(int layer, int position) {
return insertIndexForLayer(null, layer, position);
}
/**
* This method is an extended version of insertIndexForLayer()
* to support setLayer which uses Container.setZOrder which does
* not remove the component from the containment hierarchy though
* we need to ignore it when calculating the insertion index.
*
* @param comp component to ignore when determining index
* @param layer an int specifying the layer
* @param position an int specifying the position within the layer
* @return an int giving the (absolute) insertion-index
*
* @see #getIndexOf
*/
private int insertIndexForLayer(Component comp, int layer, int position) {
int i, count, curLayer;
int layerStart = -1;
int layerEnd = -1;
int componentCount = getComponentCount();
ArrayList<Component> compList =
new ArrayList<Component>(componentCount);
for (int index = 0; index < componentCount; index++) {
if (getComponent(index) != comp) {
compList.add(getComponent(index));
}
}
count = compList.size();
for (i = 0; i < count; i++) {
curLayer = getLayer(compList.get(i));
if (layerStart == -1 && curLayer == layer) {
layerStart = i;
}
if (curLayer < layer) {
if (i == 0) {
// layer is greater than any current layer
// [ ASSERT(layer > highestLayer()) ]
layerStart = 0;
layerEnd = 0;
} else {
layerEnd = i;
}
break;
}
}
// layer requested is lower than any current layer
// [ ASSERT(layer < lowestLayer()) ]
// put it on the bottom of the stack
if (layerStart == -1 && layerEnd == -1)
return count;
// In the case of a single layer entry handle the degenerative cases
if (layerStart != -1 && layerEnd == -1)
layerEnd = count;
if (layerEnd != -1 && layerStart == -1)
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