JTable表头分组 错位问题

      GroupableTableHeader header = (GroupableTableHeader)transmitterTable.getTableHeader();

      ColumnGroup g_variables = new ColumnGroup("Output Variables");
      g_variables.add(cm.getColumn(1));
      g_variables.add(cm.getColumn(2));
      g_variables.add(cm.getColumn(3));
      g_variables.add(cm.getColumn(4));
      g_variables.add(cm.getColumn(5));
//////////////////////////////////////////////
  class GroupableTableHeader extends JTableHeader {
   private static final String uiClassID = "GroupableTableHeaderUI";
   protected Vector columnGroups = null;

   public GroupableTableHeader(TableColumnModel model) {
     super(model);
     setUI(new GroupableTableHeaderUI());
     setReorderingAllowed(false);
   }
   public void updateUI(){
    setUI(new GroupableTableHeaderUI());
   }

   public void setReorderingAllowed(boolean b) {
     reorderingAllowed = false;
   }

   public void addColumnGroup(ColumnGroup g) {
     if (columnGroups == null) {
       columnGroups = new Vector();
     }
     columnGroups.addElement(g);
   }

   public Enumeration getColumnGroups(TableColumn col) {
     if (columnGroups == null) return null;
     Enumeration e = columnGroups.elements();
     while (e.hasMoreElements()) {
       ColumnGroup cGroup = (ColumnGroup)e.nextElement();
       Vector v_ret = (Vector)cGroup.getColumnGroups(col,new Vector());
       if (v_ret != null) { 
   return v_ret.elements();
       }
     }
     return null;
   }

   public void setColumnMargin() {
     if (columnGroups == null) return;
     int columnMargin = getColumnModel().getColumnMargin();
     Enumeration e = columnGroups.elements();
     while (e.hasMoreElements()) {
       ColumnGroup cGroup = (ColumnGroup)e.nextElement();
       cGroup.setColumnMargin(columnMargin);
     }
   }

  }

////////////////////////////
  class GroupableTableHeaderUI extends BasicTableHeaderUI {

     public void paint(Graphics g, JComponent c) {
       Rectangle clipBounds = g.getClipBounds();
       if (header.getColumnModel() == null) return;
       //((GroupableTableHeader)header).setColumnMargin();注释掉就 OK
       int column = 0;

       Dimension size = header.getSize();
       Rectangle cellRect  = new Rectangle(0, 0, size.width, size.height);
       Hashtable h = new Hashtable();
       int columnMargin = header.getColumnModel().getColumnMargin();


       Enumeration enumeration = header.getColumnModel().getColumns();

       while (enumeration.hasMoreElements()) {

         cellRect.height = size.height;
         cellRect.y      = 0;
         TableColumn aColumn = (TableColumn)enumeration.nextElement();
         Enumeration cGroups = ((GroupableTableHeader)header).getColumnGroups(aColumn);
         if (cGroups != null) {
           int groupHeight = 0;
           while (cGroups.hasMoreElements()) {
             ColumnGroup cGroup = (ColumnGroup)cGroups.nextElement();
             Rectangle groupRect = (Rectangle)h.get(cGroup);
             if (groupRect == null) {
               groupRect = new Rectangle(cellRect);
               Dimension d = cGroup.getSize(header.getTable());
               groupRect.width  = d.width;
               groupRect.height = d.height;    
               h.put(cGroup, groupRect);
             }
             paintCell(g, groupRect, cGroup);
             groupHeight += groupRect.height;
             cellRect.height = size.height - groupHeight;
             cellRect.y      = groupHeight;
           }
         }      

       //cellRect.width = aColumn.getWidth() + columnMargin;
       cellRect.width = aColumn.getWidth() ;

         if (cellRect.intersects(clipBounds)) {
           paintCell(g, cellRect, column);
         }
        cellRect.x += cellRect.width ;
         column++;

       }
     }

////////////////////////////
  class ColumnGroup {
    protected TableCellRenderer renderer;
    protected Vector v;
    protected String text;
    protected int margin=0;

    public ColumnGroup(String text) {
      this(null,text);
    }

    public ColumnGroup(TableCellRenderer renderer,String text) {
      if (renderer == null) {
        this.renderer = new DefaultTableCellRenderer() {
    public Component getTableCellRendererComponent(JTable table, Object value,
                           boolean isSelected, boolean hasFocus, int row, int column) {
      JTableHeader header = table.getTableHeader();
      if (header != null) {
        setForeground(header.getForeground());
        setBackground(header.getBackground());
        setFont(header.getFont());
      }
            setHorizontalAlignment(JLabel.CENTER);
            setText((value == null) ? "" : value.toString());
      setBorder(UIManager.getBorder("TableHeader.cellBorder"));
      return this;
          }
        };
      } else {
        this.renderer = renderer;
      }
      this.text = text;
      v = new Vector();
    }


    /**
     * @param obj    TableColumn or ColumnGroup
     */
    public void add(Object obj) {
      if (obj == null) { return; }
      v.addElement(obj);
    }


    /**
     * @param c    TableColumn
     * @param v    ColumnGroups
     */
    public Vector getColumnGroups(TableColumn c, Vector g) {
      g.addElement(this);
      if (v.contains(c)) return g;    
      Enumeration e = v.elements();
      while (e.hasMoreElements()) {
        Object obj = e.nextElement();
        if (obj instanceof ColumnGroup) {
          Vector groups = 
            (Vector)((ColumnGroup)obj).getColumnGroups(c,(Vector)g.clone());
          if (groups != null) return groups;
        }
      }
      return null;
    }

    public TableCellRenderer getHeaderRenderer() {
      return renderer;
    }

    public void setHeaderRenderer(TableCellRenderer renderer) {
      if (renderer != null) {
        this.renderer = renderer;
      }
    }

    public Object getHeaderValue() {
      return text;
    }

    public Dimension getSize(JTable table) {
      Component comp = renderer.getTableCellRendererComponent(
          table, getHeaderValue(), false, false,-1, -1);
      int height = comp.getPreferredSize().height; 
      int width  = 0;
      Enumeration e = v.elements();
      while (e.hasMoreElements()) {
        Object obj = e.nextElement();
        if (obj instanceof TableColumn) {
          TableColumn aColumn = (TableColumn)obj;
          width += aColumn.getWidth();
          width += margin;


        } else {
          width += ((ColumnGroup)obj).getSize(table).width;

        }
      }
      return new Dimension(width, height);
    }

    public void setColumnMargin(int margin) {
      this.margin = margin;
      Enumeration e = v.elements();
      while (e.hasMoreElements()) {
        Object obj = e.nextElement();
        if (obj instanceof ColumnGroup) {
          ((ColumnGroup)obj).setColumnMargin(margin);
        }
      }
    }
  }