Re: Problem faced while u

  To: comp.lang.java.gui
On Tue, 24 Jun 2008 02:28:57 -0700 (PDT), Chanchal
<chanchal.jacob@gmail.com> wrote, quoted or indirectly quoted someone
who said :


Here is how I did the sort arrows prior to the days of TableRowSorter.

import java.awt.Component;
import java.awt.Image;
import java.awt.Toolkit;
import java.net.URL;

import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JTable;
import javax.swing.SwingConstants;
import javax.swing.border.Border;
import javax.swing.border.EmptyBorder;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;

/**
 * renders column headings with up or down
 * pointing arrow on sort column depending
 * if sort is ascending or descending.
 *
 * @author Roedy Green
 * @version 1.0
 * @since 2002 Sep 5
 */

public class SortHeadRenderer implements TableCellRenderer
   {

   /**
    * Constructor
    *
    * @param sorter associated TableOrderer so we know which
    * column is being sorted on.
    */
   public SortHeadRenderer ( TableOrderer sorter )
      {
      this.sorter = sorter;
      }

   private TableOrderer sorter;

   /**
   * Returns the component used for drawing the cell. This method is
   * used to configure the renderer appropriately before drawing.
   *
   * @param table the <code>JTable</code> that is asking
the
   * renderer to draw; can be
<code>null</code>
   * @param value the value of the cell to be rendered.
It is
   * up to the specific renderer to
interpret
   * and draw the value. For example, if
   * <code>value</code>
   * is the string "true", it could be
rendered as a
   * string or it could be rendered as a
check
   * box that is checked. <code>null</code>
is a
   * valid value
   * @param isSelected true if the cell is to be rendered
with the
   * selection highlighted; otherwise false
   * @param hasFocus if true, render cell appropriately.
For
   * example, put a special border on the
cell, if
   * the cell can be edited, render in the
color used
   * to indicate editing
   * @param row the row index of the cell being drawn.
When
   * drawing the header, the value of
   * <code>row</code> is -1
   * @param column the column index of the cell being
drawn
   */
   public Component getTableCellRendererComponent( JTable table,
                                                   Object value,
                                                   boolean isSelected,
                                                   boolean hasFocus,
                                                   int row,
                                                   int column)
      {
      JLabel label;

      // recycle three JLabels over and over.
      switch ( sorter.howColumnSorted( column ) )
         {
         
         case TableOrderer.ASCENDING :
            label = ascendingLabel;
            break;

         case TableOrderer.DESCENDING :
            label = descendingLabel;
            break;

         default:
         case TableOrderer.UNSORTED:
            label = unsortedLabel;
            break;
         }
      label.setText( value.toString() );
      return label;

      }

   /**
    * Up pointing arrow, indicates ascending sort.
    */
   private static JLabel ascendingLabel = new JLabel("ascending");

   /**
    * Down pointing arrow, indicates descending sort.
    */
   private static JLabel descendingLabel = new JLabel("descending");

   /**
   * No arrow, indicates unsorted.
   */
   private static JLabel unsortedLabel = new JLabel("unsorted");

   private static Border noFocusBorder = new EmptyBorder(1, 1, 1, 1);
   static {
      // get Images as a resources, from jar or from classpath
      JLabel[] trio = { ascendingLabel, descendingLabel,
unsortedLabel};
      String[] resourceIcon = { "ascending.gif", "descending.gif",
null};
      for ( int i=0; i<3; i++ )
         {
         setIcon ( trio[i], resourceIcon[i] );
         trio[i].setForeground( Config.HEADER_FOREGROUND );
         trio[i].setBackground( Config.HEADER_BACKGROUND );
         // needed to make pay attention to background colour setting.
         trio[i].setOpaque( true );
         trio[i].setBorder( noFocusBorder );
         // label is centred.
         trio[i].setHorizontalAlignment( SwingConstants.CENTER );
         // text is to left of icon
         trio[i].setHorizontalTextPosition( SwingConstants.LEFT );
         }
   }

   /**
    * Attach an icon to a JLabel
    *
    * @param label JLabel to have an icon attached.
    *
    * @param gif name of resource e.g. "ascending.gif"
    * null means no gif
    */
   public static void setIcon ( JLabel label, String gif )
      {
      if ( gif == null )
         {
         label.setIcon ( null );
         }
      else
         {
         URL url = SortHeadRenderer.class.getResource( gif );
         Image image = Toolkit.getDefaultToolkit().getImage( url );
         ImageIcon icon = new ImageIcon( image );
         label.setIcon( icon );
         }
      }

   /**
  * hook this renderer up on
  * every header column.
  *
  * @param table Jtable to to use this renderer on.
  * @param sorter Associated TableOrderer
  */
   public static void install ( JTable jtable, TableOrderer sorter )
      {
      jtable.setAutoCreateColumnsFromModel( false );
      TableCellRenderer renderer = new SortHeadRenderer ( sorter );
      TableColumnModel tcm = jtable.getColumnModel();
      int cols = tcm.getColumnCount();
      for ( int i=0; i<cols; i++ )
         {
         TableColumn tc = tcm.getColumn( i );
         tc.setHeaderRenderer( renderer );
         }
      }

   }

----------------------------------------------------------

Here is how to hook up the mouseListener to notice the request to
change ascending/descending, the old fashioned way:

   /**
    * Allow user to select a new sort column.
    * Works by adding a MouseListener to the column headers.
    * Mouse listener fields requests for sorting columns.
    * Allows click, shift-click on column to select column and
ascending/descending.
    *
    * @param table the visible JTable part of the table.
    */
   public void allowUserToSelectSortColumn( JTable table )
      {
      // make available to anonymous inner class
      final JTable tableView = table;
      tableView.setColumnSelectionAllowed( false );
      JTableHeader th = tableView.getTableHeader();
      th.addMouseListener(
                         new MouseAdapter()
                            {
                            /**
                             * Handler for mouse selection of sort
column
                             * and order. Shift-click means
descending.
                             *
                             * @param event Details of event
                             */
                            public void mouseClicked( MouseEvent event
)
                               {
                               TableColumnModel columnModel =
tableView.getColumnModel();
                               int viewColumn =
columnModel.getColumnIndexAtX( event.getX() );
                               int column =
tableView.convertColumnIndexToModel( viewColumn );
                               if ( event.getClickCount() == 1 &&
column != -1 )
                                  {
                                  int shiftPressed =
event.getModifiers() & InputEvent.SHIFT_MASK;
                                  boolean ascending = ( shiftPressed
== 0 );
                                  ....
                                  }
                               }
                            }
                         );
      }

--

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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