java - 半透明窗口内的半透明 JPopupMenu - 替代方案？

Question

我不确定这是否可行，但是有没有一种方法可以安全地允许弹出窗口是半透明的，即使父容器也是半透明的？

如果不是，使用或扩展什么是替代 JPopupMenu 的明智选择？

注意:Translucent 指的是组件没有“有背景”，类似于 setOpaque(false); 的效果。谢谢。

来自用户 camickr 在 2009 年的论坛回答:

I don't know if transparency painting has changed in 1.6.0_10. Prior to that I believe transparency can only be achieved in lightweight components (ie. Swing does all the painting). JFrame, JWindow and JDialog are not lightweight because they use OS components.

In the case of a popup, it is lightweight when entirely contained within its parent frame. But a lightweight popup can not be painted outside the bounds of the frame so a JWindow (I believe) is used as the popup, which can't be transparent.

SSCCE:在半透明 JFrame 的顶部显示半透明 JWindow

import com.sun.awt.AWTUtilities;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;

public class OpaqueWindowSSCCE {

    private int countdown = 5;

    public static void main(String[] args) {
        new OpaqueWindowSSCCE();
    }

    public OpaqueWindowSSCCE() {
        final JFrame frame = new JFrame("OpaqueWindowSSCCE");
        final JWindow window = new JWindow();

        new Timer(1000, new ActionListener(){

            @Override
            public void actionPerformed(ActionEvent e) {
                if(--countdown == 0){
                    frame.dispose();
                    window.dispose();
                    System.exit(0);
                } else {
                    frame.repaint();
                }
            }

        }).start();

        frame.setContentPane(new JPanel() {

            @Override
            public void paintComponent(Graphics paramGraphics) {
                super.paintComponent(paramGraphics);
                Graphics2D g = (Graphics2D) paramGraphics.create();
                g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
                g.setColor(new Color(50, 50, 50));
                g.fillRoundRect(0, 0, getWidth(), getHeight(), 10, 10);
                g.setColor(new Color(180, 180, 180));
                g.drawString("Closing in " + countdown + " seconds", 20, 25);
            }
        });

        window.setContentPane(new JPanel() {

            @Override
            public void paintComponent(Graphics paramGraphics) {
                super.paintComponent(paramGraphics);
                Graphics2D g = (Graphics2D) paramGraphics.create();
                g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
                g.setColor(new Color(180, 180, 180));
                g.fillRoundRect(0, 0, getWidth(), getHeight(), 10, 10);
            }
        });

        frame.setUndecorated(true);

        ((JComponent) frame.getContentPane()).setOpaque(false);
        ((JComponent) window.getContentPane()).setOpaque(false);

        AWTUtilities.setWindowOpaque(frame, false);
        AWTUtilities.setWindowOpaque(window, false);

        window.setAlwaysOnTop(true);

        frame.setBounds(200,200,500,500);
        window.setBounds(600,600,200,200);
        frame.setVisible(true);
        window.setVisible(true);
    }
}

Answer 1

试试这个代码部分，虽然我用过 JWindow

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class WindowExample
{
    private JWindow window;
    private JLabel updateLabel;
    private int count = 5;
    private Timer timer;
    private int x;
    private int y;
    private ActionListener timerAction = new ActionListener()
    {
        public void actionPerformed(ActionEvent ae)
        {
            updateLabel.setText("Closing Window in " + count + " seconds...");
            count--;
            if (count == 0)
            {
                timer.stop();
                window.setVisible(false);
                window.dispose();
            }   
        }
    };

    private void createAndDisplayGUI()
    {
        final JFrame frame = new JFrame("Window Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.setUndecorated(true);
        frame.setOpacity(0.5f);
        frame.addMouseListener(new MouseAdapter()
        {
            public void mouseClicked(MouseEvent me)
            {
                x = me.getX();
                y = me.getY();
                window = new JWindow();
                JPanel contentPane = new JPanel();
                JLabel positionLabel = new JLabel(
                    "X : " + me.getX() + " Y : " + me.getY());
                updateLabel = new JLabel("TImer");  
                contentPane.setLayout(new BorderLayout(5, 5));
                contentPane.add(updateLabel, BorderLayout.CENTER);
                contentPane.add(positionLabel, BorderLayout.PAGE_END);
                window.setContentPane(contentPane);
                window.setOpacity(0.5f);
                window.setSize(200, 100);
                window.setLocation(x + window.getWidth(), y + window.getHeight());
                window.setVisible(true);
                count = 5;
                timer = new Timer(1000, timerAction);
                timer.start();
            }
        });

        frame.setSize(500, 500);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new WindowExample().createAndDisplayGUI();
            }
        });
    }
}

这是输出:

我收到警告

C:\Mine\JAVA\J2SE>javac -d classes src\OpaqueWindowSSCCE.java
src\OpaqueWindowSSCCE.java:1: warning: AWTUtilities is internal proprietary API and may be removed i
n a future release
import com.sun.awt.AWTUtilities;
                  ^
src\OpaqueWindowSSCCE.java:68: warning: AWTUtilities is internal proprietary API and may be removed
in a future release
        AWTUtilities.setWindowOpaque(frame, false);
        ^
src\OpaqueWindowSSCCE.java:69: warning: AWTUtilities is internal proprietary API and may be removed
in a future release
        AWTUtilities.setWindowOpaque(window, false);
        ^
3 warnings