Java 将非滚动组件添加到 JScrollPane

作为个人偏好，我可能会使用复合布局，类似于this example，因为它让你更好地控制组件的呈现(即更容易处理活动组件，如按钮)和它的位置.

例如，您"可以"使用JLayerAPI...

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLayer;
import javax.swing.JPanel;
import javax.swing.JScrollBar;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.plaf.LayerUI;

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

    public Main() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    JFrame frame = new JFrame();
                    frame.add(new TestPane());
                    frame.pack();
                    frame.setLocationRelativeTo(null);
                    frame.setVisible(true);
                } catch (IOException ex) {
                    Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() throws IOException {
            FixedTextLayerUI layerUI = new FixedTextLayerUI();
            layerUI.setText("this shouldn't scroll!");

            JTextArea ta = new JTextArea(20, 40);
            StringBuilder sb = new StringBuilder(1024);
            // Bring your own content ;)
            try (BufferedReader br = new BufferedReader(new InputStreamReader(getClass().getResourceAsStream("/resources/StarWarsNewHope.txt")))) {
                String text = null;
                while ((text = br.readLine()) != null) {
                    sb.append(text);
                    sb.append(System.lineSeparator());
                }
                ta.setText(sb.toString());
            }
            JLayer<JComponent> layer = new JLayer<JComponent>(new JScrollPane(ta), layerUI);
            setLayout(new BorderLayout());
            add(layer);
        }

    }

    public class FixedTextLayerUI extends LayerUI<JComponent> {

        private String text;

        public void setText(String text) {
            this.text = text;
        }

        public String getText() {
            return text;
        }

        @Override
        public void paint(Graphics g, JComponent c) {
            super.paint(g, c);

            Graphics2D g2 = (Graphics2D) g.create();

            FontMetrics fm = g2.getFontMetrics();
            int stringWidth = fm.stringWidth(getText());
            int x = c.getWidth() - stringWidth - 8;
            int y = fm.getHeight() + fm.getAscent() + 8;

            if (c instanceof JLayer) {
                JLayer layer = (JLayer) c;
                if (layer.getView() instanceof JScrollPane) {
                    JScrollPane scrollPane = (JScrollPane) layer.getView();
                    JScrollBar scrollBar = scrollPane.getVerticalScrollBar();
                    if (scrollBar.isVisible()) {
                        x -= scrollBar.getWidth();
                    }
                }
            }

            g2.drawString(text, x, y);

            g2.dispose();
        }

    }
}

有关更多详细信息，请参见How to Decorate Components with the JLayer Class.