java - Swing:创建一个有 3 个边框的 CompoundBorder？

Question

我正在创建一个 JFrame 对象，其中有一些 JPanel 并排放置。

我希望 JPanel 具有 15 像素的边距、 eclipse 刻边框和 15 像素的填充。起初我认为这会像 HTML 框模型一样非常直观，所以我尝试在 CompoundBorder 中创建 CompoundBorder，但这行不通。

这是我的代码:

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

public class StackOverFlowExample extends JFrame {

    public static void main() {
        stackOverFlowExample window = new stackOverFlowExample();
        window.setVisible(true);
    }

    public StackOverFlowExample() {
        // create buttons
        JButton foo = new JButton("foo");
        JButton bar = new JButton("bar");
        JButton foo2 = new JButton("foo2");
        JButton bar2 = new JButton("bar2");

        // create panels and add buttons to them
        JPanel left = new JPanel();
        left.setBorder(BorderFactory.createEtchedBorder());
        left.setLayout(new BoxLayout(left, BoxLayout.PAGE_AXIS));
        left.add(foo);
        left.add(bar);
        JPanel right = new JPanel();
        right.setBorder(BorderFactory.createEtchedBorder());
        right.setLayout(new BoxLayout(right, BoxLayout.PAGE_AXIS));
        right.add(foo2);
        right.add(bar2);

        // add panels to frame
        this.getContentPane().setLayout(new BoxLayout(
            getContentPane(), BoxLayout.LINE_AXIS));
        this.getContentPane().add(left);
        this.getContentPane().add(right);

        // finalize layout
        this.setPreferredSize(new Dimension(150,150));
        this.pack();
        this.setVisible(true);
    }
}

我知道我可以只使用 GridBagConstraints 或 JButton.setMargin() 创建填充，然后使用 CompoundBorder 创建带有空边框的 eclipse 刻边框。如果我不想让我的代码因这些技术而显得困惑怎么办？

Answer 1

我不确定你可能遇到什么问题，因为你没有提供你尝试过的例子，但基本过程是......

• 创建内边框要求(EtchedBorder包裹一个EmptyBorder)，例如，new CompoundBorder(emptyBorder, etchedBorder)
• 创建外边框要求(EmptyBorder包裹内复合边框)，例如，new CompoundBorder(inner, emptyBorder);
• 将此外边框应用于组件...

举个例子...

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.EtchedBorder;

public class Test1 {

    public static void main(String[] args) {
        new Test1();
    }

    public Test1() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {

            setLayout(new GridBagLayout());

            EmptyBorder emptyBorder = new EmptyBorder(15, 15, 15, 15);
            EtchedBorder etchedBorder = new EtchedBorder();

            CompoundBorder inner = new CompoundBorder(emptyBorder, etchedBorder);
            CompoundBorder outter = new CompoundBorder(inner, emptyBorder);

            JPanel panel = new JPanel(new GridBagLayout());
            panel.setBorder(outter);

            panel.add(new JButton("Hello"));

            add(panel);

        }

    }

}