Java 7 Swing：创建半透明和成形的Windows

Java 7 Swing支持具有透明和非矩形形状的窗口。以下屏幕截图显示了创建的不透明度为75％的圆形窗口。

您可以通过在JFrame上使用setOpacity方法更改其不透明度来创建半透明窗口。请注意，只有底层操作系统支持时，您才能创建半透明窗口。另外，通过调用setUndecorated(true)确保窗口未装饰。

改变窗口的形状，调用setShape内部方法componentResized方法，因此，如果窗口大小，形状被重新计算为好。

创建半透明圆形窗口的示例代码如下所示：

import java.awt.Color;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.GridBagLayout;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.geom.Ellipse2D;import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;public class TranslucentCircularFrame extends JFrame {/*** Creates a frame containing a text area and a button. The frame has a* circular shape and a 75% opacity.*/public TranslucentCircularFrame() {super("Translucent Circular Frame");setLayout(new GridBagLayout());final JTextArea textArea = new JTextArea(3, 50);textArea.setBackground(Color.GREEN);add(textArea);setUndecorated(true);// set the window's shape in the componentResized method, so// that if the window is resized, the shape will be recalculatedaddComponentListener(new ComponentAdapter() {@Overridepublic void componentResized(ComponentEvent e) {setShape(new Ellipse2D.Double(0, 0, getWidth(), getHeight()));}});// make the window translucentsetOpacity(0.75f);setLocationRelativeTo(null);setSize(250, 250);setDefaultCloseOperation(EXIT_ON_CLOSE);setVisible(true);}public static void main(String[] args) {// Create the GUI on the event-dispatching threadSwingUtilities.invokeLater(new Runnable() {@Overridepublic void run() {GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();// check if the OS supports translucencyif (ge.getDefaultScreenDevice().isWindowTranslucencySupported(GraphicsDevice.WindowTranslucency.TRANSLUCENT)) {new TranslucentCircularFrame();}}});}
}

参考： Java 7 Swing：由我们的JCG合作伙伴 Fahd Shariff在fahd.blog博客上创建半透明和成形的Windows 。