AutofitTableColumns.java

/*
 * Found at http://forum.java.sun.com/thread.jspa?forumID=54&messageID=2532529&threadID=527301
 * Author: omcgovern (http://forum.java.sun.com/profile.jspa?userID=358507)
 * Note: A few patches were made to the original to honor 'includeColumnHeaderWidth'
         and not to crash with null table header.
 */

package esmska.utils;

import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Component;
 
 
import javax.swing.text.JTextComponent;
import javax.swing.SwingUtilities;
import javax.swing.JLabel;
 
import javax.swing.JTable;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableColumnModel;
import javax.swing.table.TableColumn;
import javax.swing.table.TableCellRenderer;
 
public class AutofitTableColumns
{
 
    private static final int DEFAULT_COLUMN_PADDING = 5;
 
 
    /*
     * @param JTable aTable, the JTable to autoresize the columns on
     * @param boolean includeColumnHeaderWidth, use the Column Header width as a minimum width
     * @returns The table width, just in case the caller wants it...
     */
 
    public static int autoResizeTable ( JTable aTable, boolean includeColumnHeaderWidth )
    {
        return ( autoResizeTable ( aTable, includeColumnHeaderWidth, DEFAULT_COLUMN_PADDING ) );
    }
 
 
    /*
     * @param JTable aTable, the JTable to autoresize the columns on
     * @param boolean includeColumnHeaderWidth, use the Column Header width as a minimum width
     * @param int columnPadding, how many extra pixels do you want on the end of each column
     * @returns The table width, just in case the caller wants it...
     */
    public static int autoResizeTable ( JTable aTable, boolean includeColumnHeaderWidth, int columnPadding )
    {
        int columnCount = aTable.getColumnCount();
        int currentTableWidth = aTable.getWidth();
        int tableWidth = 0;
 
        Dimension cellSpacing = aTable.getIntercellSpacing();
 
        if ( columnCount > 0 )  // must have columns !
        {
            // STEP ONE : Work out the column widths
 
            int columnWidth[] = new int [ columnCount ];
 
            for ( int i=0; i<columnCount; i++ )
            {
                columnWidth[i] = getMaxColumnWidth ( aTable, i, includeColumnHeaderWidth, columnPadding );
 
                tableWidth += columnWidth[i];
            }
 
            // account for cell spacing too
            tableWidth += ( ( columnCount - 1 ) * cellSpacing.width );
 
            // STEP TWO : Dynamically resize each column
 
            // try changing the size of the column names area
            JTableHeader tableHeader = aTable.getTableHeader();
 
            if (tableHeader != null) {
                Dimension headerDim = tableHeader.getPreferredSize();

                // headerDim.height = tableHeader.getHeight();
                headerDim.width = tableWidth;
                tableHeader.setPreferredSize(headerDim);
            }
 
            Dimension interCellSpacing = aTable.getIntercellSpacing();
            Dimension dim = new Dimension();
            int rowHeight = aTable.getRowHeight();
 
            if ( rowHeight == 0 )
                 rowHeight = 16;    // default rowheight
 
            // System.out.println ("Row Height : " + rowHeight );
 
            dim.height = aTable.getPreferredSize().height + ( ( rowHeight + interCellSpacing.height ) * aTable.getRowCount() );
            dim.width = tableWidth;
 
            // System.out.println ("AutofitTableColumns.autoResizeTable() - Setting Table size to ( " + dim.width + ", " + dim.height + " )" );
            // aTable.setPreferredSize ( dim );
 
            TableColumnModel tableColumnModel = aTable.getColumnModel();
            TableColumn tableColumn;
 
            for ( int i=0; i<columnCount; i++ )
            {
                tableColumn = tableColumnModel.getColumn ( i );
 
                tableColumn.setPreferredWidth ( columnWidth[i] );
            }
 
            aTable.invalidate();
            aTable.doLayout();
            aTable.repaint();
        }
 
        return ( tableWidth );
    }
 
 
 
    /*
     * @param JTable aTable, the JTable to autoresize the columns on
     * @param int columnNo, the column number, starting at zero, to calculate the maximum width on
     * @param boolean includeColumnHeaderWidth, use the Column Header width as a minimum width
     * @param int columnPadding, how many extra pixels do you want on the end of each column
     * @returns The table width, just in case the caller wants it...
     */
 
    private static int getMaxColumnWidth ( JTable aTable, int columnNo,
                                           boolean includeColumnHeaderWidth,
                                           int columnPadding )
    {
        TableColumn column = aTable.getColumnModel().getColumn ( columnNo );
        Component comp = null;
        int maxWidth = 0;
 
        if ( includeColumnHeaderWidth )
        {
            TableCellRenderer headerRenderer = column.getHeaderRenderer();
            if ( headerRenderer != null )
            {
                comp = headerRenderer.getTableCellRendererComponent ( aTable, column.getHeaderValue(), false, false, 0, columnNo );
 
                if ( comp instanceof JTextComponent )
                {
                    JTextComponent jtextComp = (JTextComponent)comp;
 
                    String text = jtextComp.getText();
                    Font font = jtextComp.getFont();
                    FontMetrics fontMetrics = jtextComp.getFontMetrics ( font );
 
                    maxWidth = SwingUtilities.computeStringWidth ( fontMetrics, text );
                }
                else
                {
                    maxWidth = comp.getPreferredSize().width;
                }
            }
            else
            {
                try
                {
                    String headerText = (String)column.getHeaderValue();
                    JLabel defaultLabel = new JLabel ( headerText );
 
                    Font font = defaultLabel.getFont();
                    FontMetrics fontMetrics = defaultLabel.getFontMetrics ( font );
 
                    maxWidth = SwingUtilities.computeStringWidth ( fontMetrics, headerText );
                }
                catch ( ClassCastException ce )
                {
                    // Can't work out the header column width..
                    maxWidth = 0;
                }
            }
        }
 
        TableCellRenderer tableCellRenderer;
        // Component comp;
        int cellWidth   = 0;
 
        for (int i = 0; i < aTable.getRowCount(); i++)
        {
            tableCellRenderer = aTable.getCellRenderer ( i, columnNo );
 
            comp = tableCellRenderer.getTableCellRendererComponent ( aTable, aTable.getValueAt ( i, columnNo ), false, false, i, columnNo );
 
            if ( comp instanceof JTextComponent )
            {
                JTextComponent jtextComp = (JTextComponent)comp;
 
                String text = jtextComp.getText();
                Font font = jtextComp.getFont();
                FontMetrics fontMetrics = jtextComp.getFontMetrics ( font );
 
                int textWidth = SwingUtilities.computeStringWidth ( fontMetrics, text );
 
                maxWidth = Math.max ( maxWidth, textWidth );
            }
            else
            {
                cellWidth = comp.getPreferredSize().width;
 
                // maxWidth = Math.max ( headerWidth, cellWidth );
                maxWidth = Math.max ( maxWidth, cellWidth );
            }
        }
 
        return ( maxWidth + columnPadding );
    }
}