SystemTrayDemo

遗留问题：
win7  java.awt.TrayIcon的displayMessage方法没有生效，通知消息不能正常弹出。

许多桌面环境都有一个区域用于放置在后台运行的程序的图标，这些程序偶尔会将某些事件通知给用户。

在Windos中，这个区域称为系统托盘，而这些图标称托盘图标。

java.awt.SystemTray类是跨平台的通向系统托盘的渠道，与前面讨论过的Desktop类似，首先要调用静态的SystemTray.isSupported方法来检查Java平台是否支持系统托盘。如果支持则通过调用静态的getSystemTray方法来获取SystemTray的单例。
SystemTray类是取重要的方法是add，它使得可以添加一个TrayIcon实例，托盘图标有三个主要的属性：
（1）图标的图像
（2）当鼠标滑过图标时显示的工具提示
（3）当用户用鼠标右键点击图标时显示右键菜单

package swing.systemtray;

import java.awt.AWTException;
import java.awt.Image;
import java.awt.MenuItem;
import java.awt.PopupMenu;
import java.awt.SystemTray;
import java.awt.Toolkit;
import java.awt.TrayIcon;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

import javax.swing.Timer;

/*2015-7-8*/
public class SystemTrayTest {

    public static void main(String[] args) {
        if (!SystemTray.isSupported()) {
            System.err.println("System tray is no supported");
            return;
        }
        SystemTray tray = SystemTray.getSystemTray();
        Image image = Toolkit.getDefaultToolkit().getImage("logo.jpg");

        PopupMenu popup = new PopupMenu();
        MenuItem exitItem = new MenuItem("Exit");
        exitItem.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                System.exit(0);
            }
        });
        popup.add(exitItem);

        final TrayIcon trayIcon = new TrayIcon(image, "Your Fortune", popup);
        trayIcon.setImageAutoSize(true);
        trayIcon.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("click me");
                trayIcon.displayMessage("How do I turn this off",
                        "Right-click on the fortune cookie and select exit",
                        TrayIcon.MessageType.INFO);
            }
        });

        try {
            tray.add(trayIcon);
        } catch (AWTException e1) {
            System.err.println("TrayIcon could not be added.");
            return;
        }

        final List<String> fortunes = readFortunes();
        Timer timer = new Timer(1000, new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                int index = (int) (fortunes.size() * Math.random());
                System.out.println("is "+index);
                trayIcon.displayMessage("Your Fortune",
                        fortunes.get(index),
                        TrayIcon.MessageType.INFO);
            }
        });
        timer.start();

    }

    private static List<String> readFortunes() {
        List<String> fortunes = new ArrayList<String>();
        String path = SystemTrayTest.class.getResource("/swing/systemtray/fortunes.txt").getPath();
        try {
            Scanner in = new Scanner(new File(path));
            StringBuilder fortune = new StringBuilder();
            while (in.hasNextLine()) {
                String line = in.nextLine();
                if (line.equals("%")) {
                    fortunes.add(fortune.toString());
                    fortune.setLength(0);
                } else {
                    fortune.append(line);
                    fortune.append(" ");
                }
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        System.out.println(fortunes.size());
        System.out.println(fortunes);
        return fortunes;
    }

}

fortunes.txt

Y1000
Y1000,000
%
Y1000,000
Y1000,000,000
%
Y5000,000
Y5000,000,000
%
Y1000,000,000
Y1000,000,000,000
%

TrayIcon增加鼠标双击事件的监听：

             trayIcon.setImageAutoSize(true);//如果托盘图标空间不够，那么图标将会被裁切
             trayIcon.addMouseListener(new java.awt.event.MouseAdapter(){
                @Override
                public void mouseClicked(MouseEvent e) {
                   if(e.getClickCount()==2){   
                       showInterface();   
                    }
                }     
             }

demo2:绘制图标：

package swing.systemtray;
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Image;
import java.awt.MenuItem;
import java.awt.PopupMenu;
import java.awt.SystemTray;
import java.awt.TrayIcon;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.UIManager;

public class ActiveTray {

    public static void main(String args[]) throws Exception {
        if (SystemTray.isSupported() == false) {
            System.err.println("No system tray available");
            return;
        }
        final SystemTray tray = SystemTray.getSystemTray();
        PropertyChangeListener propListener = new PropertyChangeListener() {

            public void propertyChange(PropertyChangeEvent evt) {
                TrayIcon oldTray[] = (TrayIcon[]) evt.getOldValue();
                TrayIcon newTray[] = (TrayIcon[]) evt.getNewValue();
                System.out.println(oldTray.length + " / " + newTray.length);
            }
        };
        tray.addPropertyChangeListener("trayIcons", propListener);
        Icon icon = new BevelArrowIcon(BevelArrowIcon.UP, false, false);
        Image image = iconToImage(icon);
        PopupMenu popup = new PopupMenu();
        MenuItem item = new MenuItem("Hello, World");
        final TrayIcon trayIcon = new TrayIcon(image, "Tip Text", popup);
        ActionListener menuActionListener = new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                trayIcon.displayMessage("Good-bye", "Cruel World", 
                        TrayIcon.MessageType.WARNING);
            }
        };
        item.addActionListener(menuActionListener);
        popup.add(item);
        ActionListener actionListener = new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                tray.remove(trayIcon);
            }
        };
        trayIcon.addActionListener(actionListener);
        tray.add(trayIcon);
    }

    static Image iconToImage(Icon icon) {
        if (icon instanceof ImageIcon) {
            return ((ImageIcon) icon).getImage();
        } else {
            int w = icon.getIconWidth();
            int h = icon.getIconHeight();
            GraphicsEnvironment ge =
                    GraphicsEnvironment.getLocalGraphicsEnvironment();
            GraphicsDevice gd = ge.getDefaultScreenDevice();
            GraphicsConfiguration gc = gd.getDefaultConfiguration();
            BufferedImage image = gc.createCompatibleImage(w, h);
            Graphics2D g = image.createGraphics();
            icon.paintIcon(null, g, 0, 0);
            g.dispose();
            return image;
        }
    }

    static class BevelArrowIcon implements Icon {

        public static final int UP = 0;         // direction
        public static final int DOWN = 1;
        private static final int DEFAULT_SIZE = 16;
        private Color edge1;
        private Color edge2;
        private Color fill;
        private int size;
        private int direction;

        public BevelArrowIcon(int direction, boolean isRaisedView, 
                boolean isPressedView) {
            if (isRaisedView) {
                if (isPressedView) {
                    init(UIManager.getColor("controlLtHighlight"), 
                            UIManager.getColor("controlDkShadow"), 
                            UIManager.getColor("controlShadow"), 
                            DEFAULT_SIZE, direction);
                } else {
                    init(UIManager.getColor("controlHighlight"), 
                            UIManager.getColor("controlShadow"), 
                            UIManager.getColor("control"), 
                            DEFAULT_SIZE, direction);
                }
            } else {
                if (isPressedView) {
                    init(UIManager.getColor("controlDkShadow"), 
                            UIManager.getColor("controlLtHighlight"), 
                            UIManager.getColor("controlShadow"), 
                            DEFAULT_SIZE, direction);
                } else {
                    init(UIManager.getColor("controlShadow"), 
                            UIManager.getColor("controlHighlight"), 
                            UIManager.getColor("control"), 
                            DEFAULT_SIZE, direction);
                }
            }
        }

        public BevelArrowIcon(Color edge1, Color edge2, Color fill, 
                int size, int direction) {
            init(edge1, edge2, fill, size, direction);
        }

        @Override
        public void paintIcon(Component c, Graphics g, int x, int y) {
            switch (direction) {
                case DOWN:
                    drawDownArrow(g, x, y);
                    break;
                case UP:
                    drawUpArrow(g, x, y);
                    break;
            }
        }

        @Override
        public int getIconWidth() {
            return size;
        }

        @Override
        public int getIconHeight() {
            return size;
        }

        private void init(Color edge1, Color edge2, Color fill, 
                int size, int direction) {
            edge1 = Color.red;
            edge2 = Color.blue;
            this.edge1 = edge1;
            this.edge2 = edge2;
            this.fill = fill;
            this.size = size;
            this.direction = direction;
        }

        private void drawDownArrow(Graphics g, int xo, int yo) {
            g.setColor(edge1);
            g.drawLine(xo, yo, xo + size - 1, yo);
            g.drawLine(xo, yo + 1, xo + size - 3, yo + 1);
            g.setColor(edge2);
            g.drawLine(xo + size - 2, yo + 1, xo + size - 1, yo + 1);
            int x = xo + 1;
            int y = yo + 2;
            int dx = size - 6;
            while (y + 1 < yo + size) {
                g.setColor(edge1);
                g.drawLine(x, y, x + 1, y);
                g.drawLine(x, y + 1, x + 1, y + 1);
                if (0 < dx) {
                    g.setColor(fill);
                    g.drawLine(x + 2, y, x + 1 + dx, y);
                    g.drawLine(x + 2, y + 1, x + 1 + dx, y + 1);
                }
                g.setColor(edge2);
                g.drawLine(x + dx + 2, y, x + dx + 3, y);
                g.drawLine(x + dx + 2, y + 1, x + dx + 3, y + 1);
                x += 1;
                y += 2;
                dx -= 2;
            }
            g.setColor(edge1);
            g.drawLine(xo + (size / 2), yo + size - 1, xo 
                    + (size / 2), yo + size - 1);
        }

        private void drawUpArrow(Graphics g, int xo, int yo) {
            g.setColor(edge1);
            int x = xo + (size / 2);
            g.drawLine(x, yo, x, yo);
            x--;
            int y = yo + 1;
            int dx = 0;
            while (y + 3 < yo + size) {
                g.setColor(edge1);
                g.drawLine(x, y, x + 1, y);
                g.drawLine(x, y + 1, x + 1, y + 1);
                if (0 < dx) {
                    g.setColor(fill);
                    g.drawLine(x + 2, y, x + 1 + dx, y);
                    g.drawLine(x + 2, y + 1, x + 1 + dx, y + 1);
                }
                g.setColor(edge2);
                g.drawLine(x + dx + 2, y, x + dx + 3, y);
                g.drawLine(x + dx + 2, y + 1, x + dx + 3, y + 1);
                x -= 1;
                y += 2;
                dx += 2;
            }
            g.setColor(edge1);
            g.drawLine(xo, yo + size - 3, xo + 1, yo + size - 3);
            g.setColor(edge2);
            g.drawLine(xo + 2, yo + size - 2, xo + size - 1, yo + size - 2);
            g.drawLine(xo, yo + size - 1, xo + size, yo + size - 1);
        }
    }
}

http://stackoverflow.com/questions/12667526/adding-jpopupmenu-to-the-trayicon