为什么TrayIcon没有出现？

Question

我正在尝试在已经出现的托盘中添加TrayIcon。我是Java的新手，所以我可以调用错误的方法。有人可以帮帮我吗？我使用的代码是：

if (!SystemTray.isSupported()) {
    System.out.println("SystemTray is not supported");
    return;
}

final SystemTray tray = SystemTray.getSystemTray();
Image image = Toolkit.getDefaultToolkit().getImage("systemtray.png");
PopupMenu popup = new PopupMenu();
final TrayIcon trayIcon = new TrayIcon(image, "The Tip Text", popup);
trayIcon.setImageAutoSize(true);
try {
    tray.add(trayIcon);
} catch (AWTException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

ps。：图像位于相同的代码包中。

Answer 1

这是一个例子。看看你可能会出错的地方。

• 获取图片

  Image image= ImageIO.read(getClass().getResource("/resources/stackoverflow1.png"));
  

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• 文件结构

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• 完整的运行程序

下面

import java.awt.*;
import java.awt.event.*;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.UIManager;

public class HideToSystemTray extends JFrame {

    TrayIcon trayIcon;
    SystemTray tray;

    HideToSystemTray() throws IOException {
        super("SystemTray test");
        System.out.println("creating instance");
        try {
            System.out.println("setting look and feel");
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (Exception e) {
            System.out.println("Unable to set LookAndFeel");
        }
        if (SystemTray.isSupported()) {
            System.out.println("system tray supported");
            tray = SystemTray.getSystemTray();

            Image image = ImageIO.read(getClass().getResource("/resources/stackoverflow1.png"));
            ActionListener exitListener = new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                    System.out.println("Exiting....");
                    System.exit(0);
                }
            };
            PopupMenu popup = new PopupMenu();
            MenuItem defaultItem = new MenuItem("Exit");
            defaultItem.addActionListener(exitListener);
            popup.add(defaultItem);
            defaultItem = new MenuItem("Open");
            defaultItem.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                    setVisible(true);
                    setExtendedState(JFrame.NORMAL);
                }
            });
            popup.add(defaultItem);
            trayIcon = new TrayIcon(image, "SystemTray Demo", popup);
            trayIcon.setImageAutoSize(true);
        } else {
            System.out.println("system tray not supported");
        }
        addWindowStateListener(new WindowStateListener() {
            public void windowStateChanged(WindowEvent e) {
                if (e.getNewState() == ICONIFIED) {
                    try {
                        tray.add(trayIcon);
                        setVisible(false);
                        System.out.println("added to SystemTray");
                    } catch (AWTException ex) {
                        System.out.println("unable to add to tray");
                    }
                }
                if (e.getNewState() == 7) {
                    try {
                        tray.add(trayIcon);
                        setVisible(false);
                        System.out.println("added to SystemTray");
                    } catch (AWTException ex) {
                        System.out.println("unable to add to system tray");
                    }
                }
                if (e.getNewState() == MAXIMIZED_BOTH) {
                    tray.remove(trayIcon);
                    setVisible(true);
                    System.out.println("Tray icon removed");
                }
                if (e.getNewState() == NORMAL) {
                    tray.remove(trayIcon);
                    setVisible(true);
                    System.out.println("Tray icon removed");
                }
            }
        });
        setIconImage(ImageIO.read(getClass().getResource("/resources/stackoverflow1.png")));

        setVisible(true);
        setSize(300, 200);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) throws IOException {
        new HideToSystemTray();
    }
}

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• 结果

Answer 2

您的代码绝对正常，可能无法找到您的图片。 如果你正在使用eclipse，它应该位于你的项目文件夹中。

Answer 3

如果无法找到图像（因为@Leo Pflug注意到你的代码看起来很好），试试我一直在使用的这个小技巧：

// place this class in the same directory as your image
public class Resources {
    private Resources() {}
}

// then to obtain Image
Image image = javax.imageio.ImageIO.read(
    Resources.class.getResourceAsStream("systemtray.png"));

它将保证Java会在与systemtray.png（Resources.java）文件完全相同的目录中搜索Resoures.class。

我怀疑Toolkit在您将图片放在与您的代码相同的目录中时，会在其自己的指示中搜索它，从而解决问题。