有关GUI建立两图标之间连线的例子（完整）

/*

*  Copyright 29 Jun 2001 :), Inc. All Rights Reserved

*  $Id: LinkExample.java,v 1.5 2001/06/29 09:19:27 root Exp $

*  $Author hujian  Beijing . China $

*  $Contact : cutestfox@263.net $

*/

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import java.util.Vector;

public class LinkExample

{

public static void main(String argv[])

{

JFrame f = new JFrame("LinkExaple");

JLayeredPane container = new MapContainer();

f.getContentPane().add(container);

container.setLayout(null);

IconNode node[] = new IconNode[4];

for(int i = 0; i < 4; i  )

{

node[i] = new IconNode();

node[i].setSize(new Dimension(50,50));

container.add(node[i]);

}

node[0].appendLink(node[2]);

node[0].appendLink(node[1]);

node[0].appendLink(node[3]);

f.setSize(new Dimension(200,200));

f.setVisible(true);

}

}

class MapContainer extends JLayeredPane

{

public MapContainer()

{

super();

}

public void drawLine(Graphics2D g, Point start, Point end)

{

g.drawLine(start.x, start.y, end.x, end.y);

}

public void paint(Graphics g)

{

Vector links = IconNode.links ;

IconNode node1 = null, node2 = null;

Point pp = null;

for(int i = 0; i < links.size(); i  )

{

node1 = ((NodeLink)links.elementAt(i)).node1;

node2 = ((NodeLink)links.elementAt(i)).node2;

int[] p = Tools.getClosestPart( node1, node2 );

if( p != null && p[0] != -1 && p[1] != -1)

{

Graphics2D g2 = (Graphics2D)g;

g2.setStroke(new BasicStroke(3, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND));

g2.setColor(Color.darkGray);

drawLine(g2, node1.getPartPoint(p[0]), node1.getProlongationPoint(p[0]));

drawLine(g2, node1.getProlongationPoint(p[0]), node2.getProlongationPoint(p[1]));

drawLine(g2, node2.getProlongationPoint(p[1]), node2.getPartPoint(p[1]));

g2.setStroke(new BasicStroke(2, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND));

g2.setColor(Color.gray);

drawLine(g2, node1.getPartPoint(p[0]), node1.getProlongationPoint(p[0]));

drawLine(g2, node1.getProlongationPoint(p[0]), node2.getProlongationPoint(p[1]));

drawLine(g2, node2.getProlongationPoint(p[1]), node2.getPartPoint(p[1]));

}

}

super.paint(g);

}

}

class IconNode extends JComponent

{

public static Vector links = new Vector();

private int focusx =0, focusy =0;

private Vector targets = new Vector();

public static final int PART_TOP	= 0 ;

public static final int PART_RIGHT	= 1 ;

public static final int PART_BOTTOM	= 2 ;

public static final int PART_LEFT	= 3 ;

private int prolongation ;

public int getProlongation()

{

return ( prolongation = getWidth()/4 );

}

public Point getCenter()

{

return new Point(getX() getWidth()/2,getY() getHeight()/2);

}

public Point getProlongationPoint(int part)

{

getProlongation();

switch(part)

{

case PART_TOP:

return new Point(getX() getWidth()/2, getY()-prolongation);

case PART_RIGHT:

return new Point(getX() getWidth() prolongation, getY() getHeight()/2);

case PART_BOTTOM:

return new Point(getX() getWidth()/2, getY() getHeight() prolongation);

case PART_LEFT:

return new Point(getX()-prolongation, getY() getHeight()/2);

default:

return null;

}

}

public Point getPartPoint(int part)

{

switch(part)

{

case PART_TOP:

return new Point(getX() getWidth()/2, getY());

case PART_RIGHT:

return new Point(getX() getWidth(), getY() getHeight()/2);

case PART_BOTTOM:

return new Point(getX() getWidth()/2, getY() getHeight());

case PART_LEFT:

return new Point(getX(), getY() getHeight()/2);

default:

return null;

}

}

public IconNode()

{

setBorder(BorderFactory.createRaisedBevelBorder());

addMouseListener(new MouseProcess());

addMouseMotionListener(new MouseMotionProcess());

}

public void paint(Graphics g)

{

super.paint(g);

}

private class MouseProcess extends MouseAdapter

{

public void mouseClicked(MouseEvent e)

{

}

public void mousePressed(MouseEvent e)

{

focusx = e.getX(); focusy = e.getY();

if( getParent() instanceof JLayeredPane )

{

((JLayeredPane)getParent()).moveToFront(IconNode.this);

}

}

}

private class MouseMotionProcess extends MouseMotionAdapter

{

public void mouseDragged(MouseEvent e)

{

Container container = getParent();

int w = container.getWidth();

int h = container.getHeight();

int x = getX() e.getX()-focusx;

int y = getY() e.getY()-focusy;

if( x getWidth() > w ) x = w-getWidth();

if( y getHeight() > h ) y = h-getHeight();

if( x < 0 ) x = 0; if( y < 0 ) y = 0;

setLocation(x, y);

container.repaint();

container = null;

}

}

public NodeLink findLink(IconNode node)

{

return null;

}

public boolean appendLink(IconNode node)

{

if( node == null || targets.contains(node) || node == this ) return false;

targets.addElement(node);

NodeLink link = null;

for(int i = 0; i < links.size(); i  )

{

link = (NodeLink)links.elementAt(i);

if( this.hashCode() < node.hashCode() )

{

if( link.node1 == this && link.node2 == node )

break;

}

else

{

if( link.node2 == this && link.node1 == node )

break;

}

link = null;

}

if( link == null )

links.addElement(new NodeLink(this,node));

return node.appendLink(this);

}

}

class NodeLink

{

public IconNode node1 = null;

public IconNode node2 = null;

public NodeLink(IconNode n1, IconNode n2)

{

if( n1.hashCode() < n2.hashCode() )

{

node1 = n1;

node2 = n2;

}else if( n1.hashCode() > n2.hashCode() )

{

node1 = n2;

node2 = n1;

}

}

}

class Tools

{

public static Rectangle createRectangle(Point p1, Point p2)

{

if( p1 == null || p2 == null ) return null;

int w = Math.abs(p1.x-p2.x);

int h = Math.abs(p1.y-p2.y);

return new Rectangle(Math.min(p1.x,p2.x)-1, Math.min(p1.y,p2.y)-1,w 2,h 2);

}

public static Rectangle createRectangle(IconNode node1, IconNode node2)

{

if( node1 == null || node2 == null ) return null;

Point p1 = new Point(node1.getX() node1.getWidth()/2, node1.getY() node1.getHeight()/2);

Point p2 = new Point(node2.getX() node2.getWidth()/2, node2.getY() node2.getHeight()/2);

Rectangle rect = createRectangle(p1, p2);

p1 = null;

p2 = null;

return rect;

}

public static Point[] getContainsPoints(IconNode node, Rectangle rect)

{

if( node == null || rect == null ) return null;

Vector v = new Vector();

Point p = node.getPartPoint(IconNode.PART_TOP);

if( rect.contains(p) )	v.addElement(p);

p = node.getPartPoint(IconNode.PART_RIGHT);

if( rect.contains(p) )	v.addElement(p);

p = node.getPartPoint(IconNode.PART_BOTTOM);

if( rect.contains(p) )	v.addElement(p);

p = node.getPartPoint(IconNode.PART_LEFT);

if( rect.contains(p) )	v.addElement(p);

Point[] ret = new Point[v.size()];

for(int i=0;i < v.size();i  )	ret[i] = (Point)v.elementAt(i);

v.clear();	v = null;

return ret;

}

public static Point[] getClosestPoint(Point[] p1, Point[] p2)

{

if( p1 == null || p2 == null ) return null;

Point ret[] = new Point[2];

ret[0] = ret[1] = null;

int mind = Integer.MAX_VALUE , distance;

for(int i = 0; i < p1.length; i  )

{

for(int j = 0; j < p2.length; j  )

{

distance = (int)p1[i].distance(p2[j]);

if( distance < mind )

{

ret[0] = p1[i];

ret[1] = p2[j];

mind = distance;

}

}

}

return ret;

}

public static int getPart(IconNode node, Point p)

{

if( node == null || p == null ) return -1;

if( p.x == node.getX() node.getWidth()/2 && p.y == node.getY() )

return IconNode.PART_TOP;

else if( p.x == node.getX() node.getWidth() && p.y == node.getY() node.getHeight()/2 )

return IconNode.PART_RIGHT;

else if( p.x == node.getX() node.getWidth()/2 && p.y == node.getY() node.getHeight() )

return IconNode.PART_BOTTOM;

else if( p.x == node.getX() && p.y == node.getY() node.getHeight()/2 )

return IconNode.PART_LEFT;

else return -1;

}

public static int[] getClosestPart(IconNode node1, IconNode node2)

{

Point[] p = getClosestPoint(node1, node2);

if( p == null ) return null;

int[] ret = new int[2];

ret[0] = ret[1] = -1;

ret[0] = getPart(node1, p[0]);

ret[1] = getPart(node2, p[1]);

return ret;

}

public static Point[] getClosestPoint(IconNode node1,IconNode node2)

{

if( node1 == null || node2 == null ) return null;

Rectangle rect = createRectangle(node1, node2);

Point[] p1 = getContainsPoints(node1, rect);

Point[] p2 = getContainsPoints(node2, rect);

Point[] p = getClosestPoint(p1, p2);

p1 = null; p2 = null;

return p;

}

}