Re: Still problems with JTable

From:

"John B. Matthews" <nospam@nospam.invalid>

Newsgroups:

comp.lang.java.help

Date:

Wed, 22 Apr 2009 23:24:33 -0400

Message-ID:

<nospam-29E09D.23243322042009@news.aioe.org>

In article
<b22f5c74-476e-4b42-916d-23b91373a007@z9g2000yqi.googlegroups.com>,
Radwanski <anon23@comweb.nl> wrote:

[Please delete signature lines when replying.]

Thanks for the comment. Reason why I omited the use of a header
renderer is because it did not work. I tried to put ColumnNames[] as
CellContent inside the constructor. (super.... at MyJTable).
MyRenderer then receives Strings like "CellContent@45535." for the
headers. Causing a ClassCastExcpetion at MyRenderer. Omiting the use
of headers was the simplest solution. I not have an idea why. Using
CellContent and receiving Strings at MyRenderer. Leting me think it
is broken. If not mistaken I used setHeaderRenderer(new MyRenderer())
(of TableColumn)

I'm not sure where things went wrong, but here's an example of a header
renderer:

<code>
package news;

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumnModel;

public class HeaderTest {

    public static void main(String args[]) {
        EventQueue.invokeLater(new Runnable() {
            //@Override

            public void run() {
                HeaderTest.createGUI();
            }
        });
    }

    private static void createGUI() {
        String rows[][] = {
            {"Alpha", "Aleph"}, {"Beta", "Beth"}, {"Gamma", "Gimel"}
        };
        String cols[] = {"Ordinal", "Cardinal"};

        JTable table = new JTable(rows, cols);
        JScrollPane scrollPane = new JScrollPane(table);

        TableCellRenderer renderer = new HeaderRenderer();
        TableColumnModel columnModel = table.getColumnModel();
        columnModel.getColumn(0).setHeaderRenderer(renderer);
        columnModel.getColumn(1).setHeaderRenderer(renderer);

        JFrame frame = new JFrame("HeaderTest");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(scrollPane, BorderLayout.CENTER);
        frame.setSize(256, 128);
        frame.setVisible(true);
    }
}

class HeaderRenderer extends JLabel implements TableCellRenderer {

    public HeaderRenderer() {
        this.setOpaque(true);
        this.setBorder(UIManager.getBorder("TableHeader.cellBorder"));
    }

    //@Override
    public Component getTableCellRendererComponent(
            JTable table, Object value, boolean isSelected,
            boolean hasFocus, int row, int col) {
        this.setText((String)value);
        return this;
    }
}
</code>

--
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>