Name: dbT83986 Date: 04/25/99


// Construst some frame that contains the following scroll pane
.
.
// The problem
JScrollPane sp = new ScrollPane(...);
JScrollBar sb = sp.getVerticalScrollBar();
sb.setPrefferedSize(new Dimension(30,30));
.
.

In this case, the ScrollBar will be about twice wider then the default.
Its arrow button will get wider too, but they will not get 'higher'
in order to become a square (as they are in the default situation).

There is no way to change it with the existing interfaces of the JScrollBar
and/or its UI class.

The problem is caused by the following method in the
package javax.swing.plaf.basic.BasicArrowButton class:

public Dimension getPreferredSize()
{
  return new Dimension(16, 16);
}


Here is a code you can copy-paste, compile and run:


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

public class ScrollBarDemo
{
 public static void main(String[] str)
 {
  ScrollBarDemo s = new ScrollBarDemo();
 }

 public ScrollBarDemo()
 {
  try
  {
   UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
  }
  catch (Exception exc)
  {
   System.err.println("Error loading L&F: " + exc);
   System.exit(0);
  }

  JFrame frame = new JFrame();

  frame.addWindowListener(new WindowAdapter()
   {
    public void windowClosing(WindowEvent e)
    {
     System.exit(0);
    }
   });

  JPanel panel = new JPanel();

  JPanel p1 = new JPanel(new BorderLayout());

  JComboBox cb = new JComboBox(new String[] {"a","b","c","d","e","f"});
  cb.setMaximumRowCount(5);
  p1.add(cb, BorderLayout.NORTH);

  JScrollPane sp = new JScrollPane(p1);

  sp.setPreferredSize(new Dimension(200,200));

  sp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
  sp.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);

  // This is the code 'widening' the scrollbars. The arrow buttons get wider too,
  // but their height (or width in the case of the horizontal scroll bar) does not
  // get larger proportionally.
  sp.getVerticalScrollBar().setPreferredSize(new Dimension(30,30));
  sp.getHorizontalScrollBar().setPreferredSize(new Dimension(30,30));

  panel.add(sp);

  frame.setContentPane(panel);
  frame.pack();
  frame.setVisible(true);
 }
}
(Review ID: 57306)
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