java - JComboBox 的圆角

Question

我想让 JComboBox 有圆角。我带着这个代码:

public class BPosCmbBox extends JCboEdc {

    public BPosCmbBox() {
       super();
       setBorder(new RoundBorder());
    }

    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;
        g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_LCD_HRGB);
        super.paint(g); //To change body of generated methods, choose Tools | Templates.
    }

}



public class RoundBorder extends AbstractBorder {

    Color bgColor = new Color(0, 0, 0, 220);

    public void paintBorder(Component c, Graphics g, int x, int y, int width, int height) {
        ((Graphics2D) g).setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        ((Graphics2D) g).setColor(bgColor);
        ((Graphics2D) g).drawRoundRect(x, y, width - 1, height - 1, 12, 12);
    }

    public Insets getBorderInsets(Component c) {
        return new Insets(3, 6, 3, 3);
    }

    public Insets getBorderInsets(Component c, Insets insets) {
        insets.top = insets.left = insets.bottom = insets.right = 3;
        return insets;
    }
}

但里面还是这样的方形盒子

有什么办法可以去掉里面的方框吗？这也可能有带圆角的下拉列表吗？

Answer 1

这是我的版本，使用 BasicComboBoxUI 而不是 MetalComboBoxUI:

import java.awt.*;
import java.awt.geom.*;
import java.util.*;
import javax.accessibility.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import javax.swing.plaf.basic.*;

public class RoundedCornerComboBoxTest {
  private static final Color BACKGROUND = Color.BLACK;
  private static final Color FOREGROUND = Color.WHITE;
  private static final Color SELECTIONFOREGROUND = Color.ORANGE;
  private JComponent makeUI() {
    UIManager.put("ComboBox.foreground", FOREGROUND);
    UIManager.put("ComboBox.background", BACKGROUND);
    UIManager.put("ComboBox.selectionForeground", SELECTIONFOREGROUND);
    UIManager.put("ComboBox.selectionBackground", BACKGROUND);

    UIManager.put("ComboBox.buttonDarkShadow", BACKGROUND);
    UIManager.put("ComboBox.buttonBackground", FOREGROUND);
    UIManager.put("ComboBox.buttonHighlight",  FOREGROUND);
    UIManager.put("ComboBox.buttonShadow",     FOREGROUND);

    UIManager.put("ComboBox.border", new RoundedCornerBorder());
    JComboBox<String> combo1 = new JComboBox<>(makeModel());
    combo1.setUI(new BasicComboBoxUI());
    Object o = combo1.getAccessibleContext().getAccessibleChild(0);
    if (o instanceof JComponent) {
      JComponent c = (JComponent) o;
      c.setBorder(new RoundedCornerBorder());
      c.setForeground(FOREGROUND);
      c.setBackground(BACKGROUND);
    }
    combo1.addPopupMenuListener(new HeavyWeightContainerListener());

    UIManager.put("ComboBox.border", new RoundedCornerBorder1());
    JComboBox<String> combo2 = new JComboBox<>(makeModel());
    combo2.setUI(new BasicComboBoxUI());
    o = combo2.getAccessibleContext().getAccessibleChild(0);
    if (o instanceof JComponent) {
      JComponent c = (JComponent) o;
      c.setBorder(new RoundedCornerBorder2());
      c.setForeground(FOREGROUND);
      c.setBackground(BACKGROUND);
    }
    combo2.addPopupMenuListener(new HeavyWeightContainerListener());

    JPanel p = new JPanel();
    p.add(combo1);
    p.add(combo2);
    p.setOpaque(true);
    p.setBackground(Color.GRAY);
    return p;
  }
  private static DefaultComboBoxModel<String> makeModel() {
    DefaultComboBoxModel<String> m = new DefaultComboBoxModel<>();
    m.addElement("1234");
    m.addElement("5555555555555555555555");
    m.addElement("6789000000000");
    return m;
  }
  public static void main(String... args) {
    EventQueue.invokeLater(() -> {
      JFrame f = new JFrame();
      f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
      f.getContentPane().add(new RoundedCornerComboBoxTest().makeUI());
      f.setSize(320, 240);
      f.setLocationRelativeTo(null);
      f.setVisible(true);
    });
  }
}

class HeavyWeightContainerListener implements PopupMenuListener {
  @Override public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
    EventQueue.invokeLater(new Runnable() {
      @Override public void run() {
        JComboBox combo = (JComboBox) e.getSource();
        Accessible a = combo.getUI().getAccessibleChild(combo, 0);
        if (a instanceof BasicComboPopup) {
          BasicComboPopup pop = (BasicComboPopup) a;
          Container top = pop.getTopLevelAncestor();
          if (top instanceof JWindow) {
            //http://ateraimemo.com/Swing/DropShadowPopup.html
            System.out.println("HeavyWeightContainer");
            ((JWindow) top).setBackground(new Color(0x0, true));
          }
        }
      }
    });
  }
  @Override public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {}
  @Override public void popupMenuCanceled(PopupMenuEvent e) {}
}

class RoundedCornerBorder extends AbstractBorder {
  protected static final int ARC = 12;
  @Override public void paintBorder(
      Component c, Graphics g, int x, int y, int width, int height) {
    Graphics2D g2 = (Graphics2D) g.create();
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                        RenderingHints.VALUE_ANTIALIAS_ON);
    int r = ARC;
    int w = width  - 1;
    int h = height - 1;

    Area round = new Area(new RoundRectangle2D.Float(x, y, w, h, r, r));
    if (c instanceof JPopupMenu) {
      g2.setPaint(c.getBackground());
      g2.fill(round);
    } else {
      Container parent = c.getParent();
      if (Objects.nonNull(parent)) {
        g2.setPaint(parent.getBackground());
        Area corner = new Area(new Rectangle2D.Float(x, y, width, height));
        corner.subtract(round);
        g2.fill(corner);
      }
    }
    g2.setPaint(c.getForeground());
    g2.draw(round);
    g2.dispose();
  }
  @Override public Insets getBorderInsets(Component c) {
    return new Insets(4, 8, 4, 8);
  }
  @Override public Insets getBorderInsets(Component c, Insets insets) {
    insets.set(4, 8, 4, 8);
    return insets;
  }
}

class RoundedCornerBorder1 extends RoundedCornerBorder {
  //http://ateraimemo.com/Swing/RoundedComboBox.html
  @Override public void paintBorder(
      Component c, Graphics g, int x, int y, int width, int height) {
    Graphics2D g2 = (Graphics2D) g.create();
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                        RenderingHints.VALUE_ANTIALIAS_ON);
    int r = ARC;
    int w = width  - 1;
    int h = height - 1;

    Area round = new Area(new RoundRectangle2D.Float(x, y, w, h, r, r));
    Rectangle b = round.getBounds();
    b.setBounds(b.x, b.y + r, b.width, b.height - r);
    round.add(new Area(b));

    Container parent = c.getParent();
    if (Objects.nonNull(parent)) {
      g2.setPaint(parent.getBackground());
      Area corner = new Area(new Rectangle2D.Float(x, y, width, height));
      corner.subtract(round);
      g2.fill(corner);
    }

    g2.setPaint(c.getForeground());
    g2.draw(round);
    g2.dispose();
  }
}

class RoundedCornerBorder2 extends RoundedCornerBorder {
  @Override public void paintBorder(
      Component c, Graphics g, int x, int y, int width, int height) {
    Graphics2D g2 = (Graphics2D) g.create();
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                        RenderingHints.VALUE_ANTIALIAS_ON);
    int r = ARC;
    int w = width  - 1;
    int h = height - 1;

    Path2D.Float p = new Path2D.Float();
    p.moveTo(x, y);
    p.lineTo(x, y + h - r);
    p.quadTo(x, y + h, x + r, y + h);
    p.lineTo(x + w - r, y + h);
    p.quadTo(x + w, y + h, x + w, y + h - r);
    p.lineTo(x + w, y);
    p.closePath();
    Area round = new Area(p);

    g2.setPaint(c.getBackground());
    g2.fill(round);

    g2.setPaint(c.getForeground());
    g2.draw(round);
    g2.setPaint(c.getBackground());
    g2.drawLine(x + 1, y, x + width - 2, y);
    g2.dispose();
  }
}