File	Doc	Category	Size	Date	Package
JLayeredPane.java	API Doc	Java SE 5 API	28147	Fri Aug 26 14:57:56 BST 2005	javax.swing

JLayeredPane

• java.lang.Object
  • java.awt.Component
    • java.awt.Container
      • javax.swing.JComponent

layeredPane.add(child, JLayeredPane.DEFAULT_LAYER);
or
layeredPane.add(child, new Integer(10));

layeredPaneParent.setLayer(child, 10)

5a, 5b, 5c, 2a, 2b, 2c, 1a 

5a, 5b, 5c, 5x, 2a, 2b, 2c, 1a 

5a, 5b, 5z, 5c, 5x, 2a, 2b, 2c, 1a 

5a, 5b, 5z, 5c, 5x, 3a, 2a, 2b, 2c, 1a 

Fields Summary
public static final Integer	DEFAULT_LAYER Convenience object defining the Default layer. Equivalent to new Integer(0).
public static final Integer	PALETTE_LAYER Convenience object defining the Palette layer. Equivalent to new Integer(100).
public static final Integer	MODAL_LAYER Convenience object defining the Modal layer. Equivalent to new Integer(200).
public static final Integer	POPUP_LAYER Convenience object defining the Popup layer. Equivalent to new Integer(300).
public static final Integer	DRAG_LAYER Convenience object defining the Drag layer. Equivalent to new Integer(400).
public static final Integer	FRAME_CONTENT_LAYER Convenience object defining the Frame Content layer. This layer is normally only use to positon the contentPane and menuBar components of JFrame. Equivalent to new Integer(-30000).
public static final String	LAYER_PROPERTY Bound property
private Hashtable	componentToLayer
private boolean	optimizedDrawingPossible

Constructors Summary
public JLayeredPane() Create a new JLayeredPane ////////////////////////////////////////////////////////////////////////////// //// Container Override methods ////////////////////////////////////////////////////////////////////////////// setLayout(null);

Methods Summary
protected void	addImpl(java.awt.Component comp, java.lang.Object constraints, int index) int layer = DEFAULT_LAYER.intValue(); 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();
public javax.accessibility.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. return an AccessibleJLayeredPane that serves as the AccessibleContext of this JLayeredPane if (accessibleContext == null) { accessibleContext = new AccessibleJLayeredPane(); } return accessibleContext;
public int	getComponentCountInLayer(int layer) 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 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;
protected java.util.Hashtable	getComponentToLayer() Returns the hashtable that maps components to layers. return the Hashtable used to map components to their layers if(componentToLayer == null) componentToLayer = new Hashtable<Component,Integer>(4); return componentToLayer;
public java.awt.Component[]	getComponentsInLayer(int layer) 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 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;
public int	getIndexOf(java.awt.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. param c the Component to check return an int specifying the component's index int i, count; count = getComponentCount(); for(i = 0; i < count; i++) { if(c == getComponent(i)) return i; } return -1;
public int	getLayer(java.awt.Component c) Returns the layer attribute for the specified Component. param c the Component to check return an int specifying the component's current layer Integer i; if(c instanceof JComponent) i = (Integer)((JComponent)c).getClientProperty(LAYER_PROPERTY); else i = (Integer)getComponentToLayer().get((Component)c); if(i == null) return DEFAULT_LAYER.intValue(); return i.intValue();
public static int	getLayer(javax.swing.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(). param c the JComponent to check return an int specifying the component's layer Integer i; if((i = (Integer)c.getClientProperty(LAYER_PROPERTY)) != null) return i.intValue(); return DEFAULT_LAYER.intValue();
public static javax.swing.JLayeredPane	getLayeredPaneAbove(java.awt.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. 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 if(c == null) return null; Component parent = c.getParent(); while(parent != null && !(parent instanceof JLayeredPane)) parent = parent.getParent(); return (JLayeredPane)parent;
protected java.lang.Integer	getObjectForLayer(int layer) Returns the Integer object associated with a specified layer. param layer an int specifying the layer return an Integer object for that 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;
public int	getPosition(java.awt.Component c) 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 int i, count, startLayer, curLayer, startLocation, pos = 0; count = 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;
public int	highestLayer() 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 if(getComponentCount() > 0) return getLayer(getComponent(0)); return 0;
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. 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 return insertIndexForLayer(null, layer, position);
private int	insertIndexForLayer(java.awt.Component comp, int layer, int 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 heirarchy 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 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) layerStart = layerEnd; // If we are adding to the bottom, return the last element if (position == -1) return layerEnd; // Otherwise make sure the requested position falls in the // proper range if (position > -1 && layerStart + position <= layerEnd) return layerStart + position; // Otherwise return the end of the layer return layerEnd;
public boolean	isOptimizedDrawingEnabled() 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 return optimizedDrawingPossible;
public int	lowestLayer() 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 int count = getComponentCount(); if(count > 0) return getLayer(getComponent(count-1)); return 0;
public void	moveToBack(java.awt.Component c) 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) setPosition(c, -1);
public void	moveToFront(java.awt.Component c) 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) setPosition(c, 0);
public void	paint(java.awt.Graphics g) Paints this JLayeredPane within the specified graphics context. param g the Graphics context within which to paint 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);
protected java.lang.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. return a string representation of this JLayeredPane. String optimizedDrawingPossibleString = (optimizedDrawingPossible ? "true" : "false"); return super.paramString() + ",optimizedDrawingPossible=" + optimizedDrawingPossibleString;
public static void	putLayer(javax.swing.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). param c the JComponent to move param layer an int specifying the layer to move it to see #setLayer /// MAKE SURE THIS AND setLayer(Component c, int layer, int position) are SYNCED Integer layerObj; layerObj = new Integer(layer); c.putClientProperty(LAYER_PROPERTY, layerObj);
public void	remove(int index) 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 Component c = getComponent(index); super.remove(index); if (c != null && !(c instanceof JComponent)) { getComponentToLayer().remove(c); } validateOptimizedDrawing();
public void	removeAll() Removes all the components from this container. since 1.5 Component[] children = getComponents(); Hashtable 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();
public void	setLayer(java.awt.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. 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 setLayer(c, layer, -1);
public void	setLayer(java.awt.Component c, int layer, int position) 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 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((Component)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());
public void	setPosition(java.awt.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. 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 setLayer(c, getLayer(c), position);
private void	validateOptimizedDrawing() boolean layeredComponentFound = false; synchronized(getTreeLock()) { Integer layer = null; for (Component c : getComponents()) { layer = null; if(c instanceof 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;