未修饰的JFrame阴影

基本上，您需要制作一系列的图层。

• Jframe

• ShadowPanel

• and content…

  import java.awt.AlphaComposite;
  import java.awt.BorderLayout;
  import java.awt.Color;
  import java.awt.Dimension;
  import java.awt.EventQueue;
  import java.awt.Graphics;
  import java.awt.Graphics2D;
  import java.awt.GridBagLayout;
  import javax.swing.Jframe;
  import javax.swing.JLabel;
  import javax.swing.JPanel;
  import javax.swing.UIManager;
  import javax.swing.UnsupportedLookAndFeelException;
  import javax.swing.border.EmptyBorder;
  

  public class ShadowWindow {

  public static void main(String[] args) {    new ShadowWindow();}public ShadowWindow() {    EventQueue.invokeLater(new Runnable() {        @Override        public void run() { try {     UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { } Jframe frame = new Jframe("Testing"); frame.setUndecorated(true); frame.setBackground(new Color(0, 0, 0, 0)); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); frame.setContentPane(new ShadowPane()); JPanel panel = new JPanel(new GridBagLayout()); panel.add(new JLabel("Look ma, no hands")); frame.add(panel); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true);        }    });}public class ShadowPane extends JPanel {    public ShadowPane() {        setLayout(new BorderLayout());        setOpaque(false);        setBackground(Color.BLACK);        setBorder(new EmptyBorder(0, 0, 10, 10));    }    @Override    public Dimension getPreferredSize() {        return new Dimension(200, 200);    }    @Override    protected void paintComponent(Graphics g) {        super.paintComponent(g);        Graphics2D g2d = (Graphics2D) g.create();        g2d.setComposite(AlphaComposite.SrcOver.derive(0.5f));        g2d.fillRect(10, 10, getWidth(), getHeight());        g2d.dispose();    }}

  }