Briefly having a look at some of my old code, I've used
JTable.prepareRenderer on TableColumn.getCellRenderer. Then it's a
matter of setting the column preferred width to the maximum of the
preferred widths given by the renderer component. You probably want to
consider the header as well.

String length will give you the number of characters in the text. If you
set the width to one pixel per character, it's probably going to be a
tad short.

Tom Hawtin

If I understand your problem. Here is a method that will expand the
columns to the largest cell\column..

   public void calcColumnWidths(JTable table)
    {
        JTableHeader header = table.getTableHeader();
        TableCellRenderer defaultHeaderRenderer = null;

        if (header != null)
            defaultHeaderRenderer = header.getDefaultRenderer();

        TableColumnModel columns = table.getColumnModel();
        TableModel data = table.getModel();
        int margin = columns.getColumnMargin(); // only JDK1.3
        int rowCount = data.getRowCount();
        int totalWidth = 0;

        for (int i = columns.getColumnCount() - 1; i >= 0; --i)
        {
            TableColumn column = columns.getColumn(i);
            int columnIndex = column.getModelIndex();
            int width = -1;

            TableCellRenderer h = column.getHeaderRenderer();

            if (h == null)
                h = defaultHeaderRenderer;

            if (h != null) // Not explicitly impossible
            {
                Component c = h.getTableCellRendererComponent(table, column
                        .getHeaderValue(), false, false, -1, i);
                width = c.getPreferredSize().width;
            }

            for (int row = rowCount - 1; row >= 0; --row)
            {
                TableCellRenderer r = table.getCellRenderer(row, i);
                Component c = r.getTableCellRendererComponent(table, data
                        .getValueAt(row, columnIndex), false, false,
row, i);
                width = Math.max(width, c.getPreferredSize().width);
            }

            if (width >= 0)
                column.setPreferredWidth(width + margin); // <1.3:
without margin
            else
                totalWidth += column.getPreferredWidth();
        }
    }

Thanks in Advance...
IchBin, Pocono Lake, Pa, USA              http://weconsultants.phpnet.us
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