JTextField橫向滾動java swing

Question

我有一個JTextField在JPanel內。用戶可以在文本框中鍵入文字，但是當文本超出文本框的屏幕時，應該出現橫向滾動。此時，如果用戶退格文本並縮小文本框屏幕內的文本，滾動應該消失。所以基本上滾動應該只在需要的時候出現。怎麼做 ？請幫助。

Answer 1

如果你不喜歡JScrollPane + JTextField的行爲，你需要使用JScrollBar#setModel(BoundedRangeModel) + JTextField#getHorizontalVisibility()：

import java.awt.*; 
import javax.swing.*; 
import javax.swing.plaf.basic.BasicScrollBarUI; 

public class TextFieldScrollBarTest { 
    private static final String TEXT = "javascript:(function(){var l=location,m=l.href.match('^(https?://)(.+)(api[^+]+|technotes[^+]+)');if(m)l.href=m[1]+'docs.oracle.com/javase/8/docs/'+decodeURIComponent(m[3]).replace(/\\+.*$/,'').replace(/\\[\\]/g,':A').replace(/, |\\(|\\)/g,'-');}());"; 

    public JComponent makeUI() { 
    JScrollPane scroll = new JScrollPane(new JTextField(TEXT)); 
    scroll.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS); 

    JTextField textField = new JTextField(TEXT); 
    JScrollBar scroller = new JScrollBar(Adjustable.HORIZONTAL) { 
     @Override public void updateUI() { 
     //super.updateUI(); 
     setUI(new ArrowButtonlessScrollBarUI()); 
     } 
     @Override public Dimension getPreferredSize() { 
     Dimension d = super.getPreferredSize(); 
     d.height = 5; 
     return d; 
     } 
    }; 
    scroller.setModel(textField.getHorizontalVisibility()); 

    Box box = Box.createVerticalBox(); 
    box.add(scroll); 
    box.add(Box.createVerticalStrut(50)); 
    box.add(textField); 
    box.add(Box.createVerticalStrut(2)); 
    box.add(scroller); 
    box.add(Box.createVerticalGlue()); 

    JPanel p = new JPanel(new BorderLayout()); 
    p.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20)); 
    p.add(box, BorderLayout.NORTH); 
    return p; 
    } 

    public static void main(String... args) { 
    EventQueue.invokeLater(() -> { 
     JFrame f = new JFrame(); 
     f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); 
     f.getContentPane().add(new TextFieldScrollBarTest().makeUI()); 
     f.setSize(320, 240); 
     f.setLocationRelativeTo(null); 
     f.setVisible(true); 
    }); 
    } 
} 

class ZeroSizeButton extends JButton { 
    private static final Dimension ZERO_SIZE = new Dimension(); 
    @Override public Dimension getPreferredSize() { 
    return ZERO_SIZE; 
    } 
} 

class ArrowButtonlessScrollBarUI extends BasicScrollBarUI { 
    private static final Color DEFAULT_COLOR = new Color(220, 100, 100); 
    private static final Color DRAGGING_COLOR = new Color(200, 100, 100); 
    private static final Color ROLLOVER_COLOR = new Color(255, 120, 100); 
    @Override protected JButton createDecreaseButton(int orientation) { 
    return new ZeroSizeButton(); 
    } 
    @Override protected JButton createIncreaseButton(int orientation) { 
    return new ZeroSizeButton(); 
    } 
    @Override protected void paintTrack(Graphics g, JComponent c, Rectangle r) { 
    //Graphics2D g2 = (Graphics2D) g.create(); 
    //g2.setPaint(new Color(100, 100, 100)); 
    //g2.fillRect(r.x, r.y, r.width - 1, r.height - 1); 
    //g2.dispose(); 
    } 
    @Override protected void paintThumb(Graphics g, JComponent c, Rectangle r) { 
    JScrollBar sb = (JScrollBar) c; 
    if (!sb.isEnabled()) { 
     return; 
    } 
    BoundedRangeModel m = sb.getModel(); 
    int iv = m.getMaximum() - m.getMinimum() - m.getExtent() - 1; // -1: bug? 
    if (iv > 0) { 
     Graphics2D g2 = (Graphics2D) g.create(); 
     g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 
     Color color; 
     if (isDragging) { 
     color = DRAGGING_COLOR; 
     } else if (isThumbRollover()) { 
     color = ROLLOVER_COLOR; 
     } else { 
     color = DEFAULT_COLOR; 
     } 
     g2.setPaint(color); 
     g2.fillRect(r.x, r.y, r.width - 1, r.height - 1); 
     g2.dispose(); 
    } 
    } 
}