java - JSeparator 虚线样式

Question

我在我的 java swing 应用程序中使用 JSeparator。正常执行使分隔线正常；但我需要的是分隔符应该是虚线(就像我们创建虚线边框一样)。我们有什么办法可以做到这一点吗？

谢谢

Answer 1

创建自定义 JSeparator ，您可以重写 BasicSeparatorUI 的 paint() 方法，讨论here ，并使用虚线 Stroke 绘制线条，如图所示 here .

附录:一种更熟悉的方法会覆盖 paintComponent()，如已接受的 answer 所示。并方便地封装在这个StrokedSeparator中。下面的变体将 drawLine() 替换为 draw()使用 Line2D，它利用了笔划的几何形状。

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Stroke;
import java.awt.geom.Line2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSeparator;
import static javax.swing.JSeparator.*;

/**
 * @see https://stackoverflow.com/a/74657060/230513
 */
public class StrokeSepTest {

    private static final int N = 10;

    private void display() {
        var f = new JFrame("StrokeSepTest");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        var stroke = new BasicStroke(8.0f, BasicStroke.CAP_BUTT,
            BasicStroke.JOIN_MITER, 10.0f, new float[]{5.0f}, 0.0f);
        var panel = new JPanel(new GridLayout(0, 1)) {
            @Override
            public Dimension getPreferredSize() {
                return new Dimension(320, 240);
            }
        };
        panel.setBackground(Color.white);
        for (int i = 0; i < N; i++) {
            Color color = Color.getHSBColor((float) i / N, 1, 1);
            panel.add(new StrokedSeparator(stroke, HORIZONTAL, color));
        }
        f.add(panel);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    // @see https://stackoverflow.com/a/74657060/230513 */
    private static class StrokedSeparator extends JSeparator {

        private Stroke stroke;

        public StrokedSeparator() {
            this(new BasicStroke(1F), HORIZONTAL);
        }

        public StrokedSeparator(int orientation) {
            this(new BasicStroke(1F), orientation);
        }

        public StrokedSeparator(Stroke stroke) {
            this(stroke, HORIZONTAL);
        }

        public StrokedSeparator(Stroke stroke, int orientation) {
            super(orientation);
            this.stroke = stroke;
        }

        public StrokedSeparator(Stroke stroke, int orientation, Color color) {
            super(orientation);
            super.setForeground(color);
            this.stroke = stroke;
        }

        @Override
        public void paintComponent(Graphics g) {
            var graphics = (Graphics2D) g;
            var s = getSize();
            graphics.setStroke(stroke);
            graphics.setColor(getForeground());
            if (getOrientation() == JSeparator.VERTICAL) {
                graphics.draw(new Line2D.Double(0, 0, 0, s.height));
            } else // HORIZONTAL
            {
                graphics.draw(new Line2D.Double(0, 0, s.width, 0));
            }
        }
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new StrokeSepTest()::display);
    }
}