Question

我正在尝试创建一个跟随鼠标的圆形窗口，并将点击传递给底层窗口。

我是用Python和Qt做的（参见Python overlay window），但后来切换到了Java和Swing。但是我无法使窗口透明。我尝试了this method但它不起作用，但我认为我的系统支持透明度，因为如果我启动Screencast-O-Matic（在Java中），矩形实际上是透明的。

我怎样才能实现这样的目标？（我在Linux KDE4上）

Answer 1

为什么Java教程How to Create Translucent and Shaped Windows无效？您使用的是最新版本的Java 6还是Java 7？在May/June issue of Java Magazine中，有一个关于需要java 7的形状和透明窗口的教程。您可能需要注册Java杂志才能阅读它。看看你是否可以在你的系统上运行它：

import java.awt.*; //Graphics2D, LinearGradientPaint, Point, Window, Window.Type;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;

/**
 * From JavaMagazine May/June 2012
 * @author josh
 */
public class ShapedAboutWindowDemo {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        //switch to the right thread
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame("About box");
                //turn of window decorations
                frame.setUndecorated(true);
                //turn off the background
                frame.setBackground(new Color(0,0,0,0));
                frame.setContentPane(new AboutComponent());
                frame.pack();
                //size the window
                frame.setSize(500, 200);
                frame.setVisible(true);
                //center on screen
                frame.setLocationRelativeTo(null);
            }
        }
        );
    }

    private static class AboutComponent extends JComponent {
        public void paintComponent(Graphics graphics) {
            Graphics2D g = (Graphics2D) graphics;

            //create a translucent gradient
            Color[] colors = new Color[]{
                           new Color(0,0,0,0)
                            ,new Color(0.3f,0.3f,0.3f,1f)
                            ,new Color(0.3f,0.3f,0.3f,1f)
                            ,new Color(0,0,0,0)};
            float[] stops = new float[]{0,0.2f,0.8f,1f};
            LinearGradientPaint paint = new LinearGradientPaint(
                                        new Point(0,0), new Point(500,0),
                                        stops,colors);
            //fill a rect then paint with text
            g.setPaint(paint);
            g.fillRect(0, 0, 500, 200);
            g.setPaint(Color.WHITE);
            g.drawString("My Killer App", 200, 100);
        }
    }
}

Answer 2

如果您使用的是Java 6，则需要使用私有API AWTUtilities。查看Java SE 6 Update 10 API了解更多详情

示例

这有点快速破解，但它可以解决这个问题

public class TransparentWindow { /** * @param args the command line arguments */ public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { @Override public void run() { MyFrame frame = new MyFrame(); frame.setUndecorated(true); String version = System.getProperty("java.version"); if (version.startsWith("1.7")) { GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment(); GraphicsDevice graphicsDevice = ge.getDefaultScreenDevice(); System.out.println("Transparent from under Java 7"); /* This won't run under Java 6, uncomment if you are using Java 7 System.out.println("isPerPixelAlphaTranslucent = " + graphicsDevice.isWindowTranslucencySupported(GraphicsDevice.WindowTranslucency.PERPIXEL_TRANSLUCENT)); System.out.println("isPerPixelAlphaTransparent = " + graphicsDevice.isWindowTranslucencySupported(GraphicsDevice.WindowTranslucency.PERPIXEL_TRANSPARENT)); System.out.println("isPerPixelAlphaTranslucent = " + graphicsDevice.isWindowTranslucencySupported(GraphicsDevice.WindowTranslucency.TRANSLUCENT)); */ frame.setBackground(new Color(0, 0, 0, 0)); } else if (version.startsWith("1.6")) { System.out.println("Transparent from under Java 6"); System.out.println("isPerPixelAlphaSupported = " + supportsPerAlphaPixel()); setOpaque(frame, false); } frame.setSize(400, 400); frame.setLocationRelativeTo(null); frame.setVisible(true); } }); } public static class MyFrame extends JFrame { public MyFrame() throws HeadlessException { setContentPane(new MyContentPane()); setDefaultCloseOperation(EXIT_ON_CLOSE); addMouseListener(new MouseAdapter() { @Override public void mouseClicked(MouseEvent e) { if (e.getClickCount() == 2) { dispose(); } } }); } } public static class MyContentPane extends JPanel { public MyContentPane() { setLayout(new GridBagLayout()); add(new JLabel("Hello, I'm a transparent frame under Java " + System.getProperty("java.version"))); setOpaque(false); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2d = (Graphics2D) g.create(); g2d.setColor(Color.BLUE); g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f)); g2d.fillRoundRect(0, 0, getWidth() - 1, getHeight() - 1, 20, 20); } } public static boolean supportsPerAlphaPixel() { boolean support = false; try { Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities"); support = true; } catch (Exception exp) { } return support; } public static void setOpaque(Window window, boolean opaque) { try { Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities"); if (awtUtilsClass != null) { Method method = awtUtilsClass.getMethod("setWindowOpaque", Window.class, boolean.class); method.invoke(null, window, opaque); // com.sun.awt.AWTUtilities.setWindowOpaque(this, opaque); // ((JComponent) window.getContentPane()).setOpaque(opaque); } } catch (Exception exp) { } } public static void setOpacity(Window window, float opacity) { try { Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities"); if (awtUtilsClass != null) { Method method = awtUtilsClass.getMethod("setWindowOpacity", Window.class, float.class); method.invoke(null, window, opacity); } } catch (Exception exp) { exp.printStackTrace(); } } public static float getOpacity(Window window) { float opacity = 1f; try { Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities"); if (awtUtilsClass != null) { Method method = awtUtilsClass.getMethod("getWindowOpacity", Window.class); Object value = method.invoke(null, window); if (value != null && value instanceof Float) { opacity = ((Float) value).floatValue(); } } } catch (Exception exp) { exp.printStackTrace(); } return opacity; } }

在Windows 7上生成

在Java 6下

在Java 7下

Answer 3

我想这会起作用，我已经尝试过了......要使JFrame或窗口透明，你需要首先解开框架Undecorated(true)。以下是示例代码：

import javax.swing.*;
import com.sun.awt.AWTUtilities;
import java.awt.Color;   

    class transFrame {
      private JFrame f=new JFrame();
      private JLabel msg=new JLabel("Hello I'm a Transparent Window");

     transFrame() {
       f.setBounds(400,150,500,500);
       f.setLayout(null);
       f.setUndecorated(true);     // Undecorates the Window
       f.setBackground(new Color(0,0,0,25));  // fourth index decides the opacity
       f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       msg.setBounds(150,250,300,25);
       f.add(msg);
       f.setVisible(true);
      }

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

     }

唯一的问题是你需要添加自己的代码以便关闭并最小化使用按钮。

Answer 4

如果你想独立完成，不使用外部lib，你可以启动一个执行的线程：

将透明窗口设置为不可见
制作桌面的屏幕截图
将此屏幕截图设为您窗口的背景图片

或者您可以使用JavaFX

Java透明窗口

4 个答案: