如何将EtchedBorder仅应用于边界的特定边？

Question

我有一个JPanel，我想添加一个EtchedBorder.Lowered只到左边框。我知道MatteBorders可以做到这一点，但我想知道是否有办法用EtchedBorder做到这一点？

Answer 1

• 使用JSeparator代替EtchedBorder.Lowered，

• 但JSeparator默认只有行，但你可以构建有趣的边框

import java.awt.BorderLayout;
import java.awt.Dimension;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSeparator;
import javax.swing.SwingUtilities;

public class NestedLayout {

    private JFrame frame = new JFrame();
    private JPanel leftPanel = new JPanel();

    public NestedLayout() {
        leftPanel.setLayout(new BorderLayout());
        leftPanel.setBorder(BorderFactory.createEmptyBorder(
                10, //top
                10, //left
                10, //bottom
                10));   //right
        leftPanel.add(new JSeparator(JSeparator.VERTICAL), BorderLayout.CENTER);
        leftPanel.setPreferredSize(new Dimension(40, 40));
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(leftPanel, BorderLayout.WEST);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new NestedLayout();
            }
        });
    }
}

Answer 2

您可以连接两个面板并在每个面板上添加“相对”的乱蓬蓬边框以重新创建蚀刻效果：

import javax.swing.*;
import java.awt.*;

public class MainFrame extends JFrame {

    public MainFrame() {
        setLayout(new BorderLayout());

        JPanel left = new JPanel();
        left.setPreferredSize(new Dimension(200, 400));
        left.setBorder(BorderFactory.createMatteBorder(0, 0, 0, 1, Color.GRAY));
        add(left, BorderLayout.WEST);

        JPanel center = new JPanel();
        center.setPreferredSize(new Dimension(200, 400));
        center.setBorder(BorderFactory.createMatteBorder(0, 1, 0, 0, Color.WHITE));
        add(center, BorderLayout.CENTER);

        setVisible(true);
        pack();
    }

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

Answer 3

您可以通过对EtchedBorder或AbstractBorder进行子类化来轻松创建自己的边框类。

此代码将完全按照您的要求执行：仅在一侧绘制的EtchedBorder。但它看起来并不好。 EtchedBorder每侧只绘制两条线（一条暗线，一条灯线）。它从线条在角落处的方式获得三维外观。如果没有绘制完整的框，它看起来不是三维的。

setBorder(new EtchedBorder() {
  public void paintBorder(Component c, Graphics g, int x, int y, int width, int height) {
    g.setColor(getShadowColor(c));
    g.drawLine(x, y + height - 2, x, y);

    g.setColor(getHighlightColor(c));
    g.drawLine(x+1, y + height - 3, x+1, y + 1);
  }
});

Answer 4

延伸Yanflea给出的答案，你可以从两个不同的面板创建一个“对立面”来复制蚀刻边框的外观。

您可以使用CompoundBorder在一个面板上创建它，如下所示：

 CompoundBorder border = BorderFactory.createCompoundBorder(
          BorderFactory.createMatteBorder(0, 0, 1, 0, Color.WHITE),
          BorderFactory.createMatteBorder(0, 0, 1, 0, Color.GRAY)
          ); // This would create A line on the bottom

这样做的好处是你也可以做两面，然后看起来像这样:(注意，这只是一个有九个面板的网格，只有中间有边框，也比一个厚<1 >请参阅下面的代码，我在面板上使用setBackground来显示每个面板的位置）

！

import javax.swing.*;
import java.awt.*;

public class Test
{
    public static void main(String[] args) 
    { 
        JFrame f = new JFrame("A Demo");
        f.setLayout(new GridLayout(3,3));
        f.setSize(400,400);
        JPanel j1 = new JPanel();       //j1.setBackground(new Color(255,0,0));
        JPanel j2 = new JPanel();       //j2.setBackground(new Color(200,0,0));
        JPanel j3 = new JPanel();       //j3.setBackground(new Color(150,0,0));
        JPanel j4 = new JPanel();       //j4.setBackground(new Color(100,0,0));
        JPanel j5 = new JPanel();       //j5.setBackground(new Color(0,255,0));
        JPanel j6 = new JPanel();       //j6.setBackground(new Color(0,200,0));
        JPanel j7 = new JPanel();       //j7.setBackground(new Color(50,0,0));
        JPanel j8 = new JPanel();       //j8.setBackground(new Color(0,150,0));
        JPanel j9 = new JPanel();       //j9.setBackground(new Color(0,100,0));
        j5.setBorder(BorderFactory.createCompoundBorder(
              BorderFactory.createMatteBorder(0, 0, 2, 2, Color.WHITE),
              BorderFactory.createMatteBorder(0, 0, 2, 2, Color.GRAY)
              ));   
        f.add(j1);
        f.add(j2);
        f.add(j3);
        f.add(j4);
        f.add(j5);
        f.add(j6);
        f.add(j7);
        f.add(j8);
        f.add(j9);  
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);   
        f.setVisible(true);
    }
}