JTable colors all cells and not only the specific cell

Question

I have a problem with a method that should change the color of one specific cell i a JTable, however all the cells change color.

This is the method I am trying to implement:

public Component cellBG(JTable table, int row, int column)
{
    TableCellRenderer renderer = table.getCellRenderer(row, column);
    Component c = table.prepareRenderer(renderer, row, column);

    Object steak = table.getValueAt(row,column);

    if(((String) steak).startsWith("+"))
    {
       c.setBackground(Color.GREEN);
    }
    else if(((String) steak).startsWith("-"))
    {
        c.setBackground(Color.RED);
    }
    else if(((String) steak).startsWith("~"))
    {
        c.setBackground(Color.YELLOW);
    }
    else if(((String) steak).equals(""))
    {
        c.setBackground(Color.WHITE);
    }

    return c;

}

my table contains 10 columns with 8 rows all containing either +, -, ~, or " ", which should result in a scattered pattern i different colors, however the tabel is colored solid in the last entri which is read.

Ass per request an SSCCE

import java.awt.Component;
import java.awt.EventQueue;
import java.awt.Color;
import java.awt.Font;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JFrame;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableCellRenderer;

public class ptf_viewer extends JFrame {

    static JTable table;
    static DefaultTableModel model;

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    ptf_viewer frame = new ptf_viewer();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }); 
    }

    public ptf_viewer(){
    getContentPane().setBackground(Color.WHITE);
    setTitle("Portable test file viewing");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(50, 50, 1024, 768);
    getContentPane().setLayout(null);

    final String[] columnNames = {"Test 1", "Test 2", "Test 3", "Test 4", "Test 5", "Test 6", "Test 7", "Test 8", "Test 9", "Test 10"};
    final Object[][] data = {
                {"+","+","","","","~","","","",""},
                {"-","+","","","","","","","",""},
                {"+","+","","","~","","","","",""},
                {"+","+","","","","","~","","",""},
                {"+","-","","~","","","","","",""},
                {"+","-","","","","","","","",""},
                {"+","-","","","","","","","",""},
                {"-","+","~","","","","","","","+"}
    };
    model = new DefaultTableModel(data, columnNames);
    table = new JTable(data, columnNames);
    table.setModel(model);
    for(int i = 0 ; i < 8 ; i++){
            cellBG(table, i, 9);
    }
    JTableHeader header = table.getTableHeader();
    header.setFont(new Font("Times New Roman", Font.BOLD, 13));
    header.setBackground(Color.black);
    header.setForeground(Color.white);

    JScrollPane scrollPane = new JScrollPane(table);
    scrollPane.setSize(988, 618);
    scrollPane.setFont(new Font("Times New Roman", Font.BOLD, 13));
    scrollPane.setLocation(10, 60);
    getContentPane().add(scrollPane);
    }
    public Component cellBG(JTable table, int row, int column)
    {
        TableCellRenderer renderer = table.getCellRenderer(row, column);
        Component c = table.prepareRenderer(renderer, row, column);

        Object bøf = table.getValueAt(row,column);

        if(((String) bøf).startsWith("+"))
        {
           c.setBackground(Color.GREEN);
        }
        else if(((String) bøf).startsWith("-"))
        {
            c.setBackground(Color.RED);
        }
        else if(((String) bøf).startsWith("~"))
        {
            c.setBackground(Color.YELLOW);
        }
        else if(((String) bøf).equals(""))
        {
            c.setBackground(Color.WHITE);
        }
        return c;
    }
    }

Looks like the renderer is shared by all the cells in your table. The last cell that is checked by the renderer will give the color to all the cells. — Jonathan Drapeau, Jul 31 '13 at 11:41
for better help sooner post an [SSCCE](http://sscce.org/), short, runnable, compilable wtih hardocded value for JTable (contains 10 columns with 8 rows all containing either +, -, ~, or " ",), question how is possble that your prepareRenderer painting something — mKorbel, Jul 31 '13 at 11:55
@JonathanDrapeau exact analysis. though not surprising, the renderer is designed to be shared :-) — kleopatra, Jul 31 '13 at 12:19

score 3 · Answer 1 · answered Jul 31 '13 at 13:38

abbisDK wrote - SSCCE made and added to question,

see by by using DefaultTableCellRenderer and Pattern.compile (one of variour ways, Strin.equals() or String.startWith, contains are another and quite easy)
the same, so very similair code could be used for prepareRenderer

.

table = new JTable(data, columnNames) {
   //logics place for prepareRenderer
};

enter image description here

from code

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.util.regex.Pattern;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableColumn;

public class Ptf_Viewer {

    private JFrame frame = new JFrame("Portable test file viewing");
    private JTable table;
    private final String[] columnNames = {"Test 1", "Test 2", "Test 3", "Test 4",
        "Test 5", "Test 6", "Test 7", "Test 8", "Test 9", "Test 10"};
    private final Object[][] data = {
        {"+", "+", "", "", "", "~", "", "", "", ""},
        {"-", "+", "", "", "", "", "", "", "", ""},
        {"+", "+", "", "", "~", "", "", "", "", ""},
        {"+", "+", "", "", "", "", "~", "", "", ""},
        {"+", "-", "", "~", "", "", "", "", "", ""},
        {"+", "-", "", "", "", "", "", "", "", ""},
        {"+", "-", "", "", "", "", "", "", "", ""},
        {"-", "+", "~", "", "", "", "", "", "", "+"}
    };
    private DefaultTableModel model = new DefaultTableModel(data, columnNames);

    public Ptf_Viewer() {
        table = new JTable(data, columnNames) {
            //logics place for prepareRenderer
        };
        table.setModel(model);
        table.setPreferredScrollableViewportSize(
                new Dimension(800, table.getPreferredSize().height));
        JTableHeader header = table.getTableHeader();
        header.setFont(new Font("Times New Roman", Font.BOLD, 13));
        header.setBackground(Color.black);
        header.setForeground(Color.white);
        for (int i = 0; i < table.getColumnCount(); i++) {
            RowColorRenderer rowRenderer = new RowColorRenderer(i);
            TableColumn column = table.getColumnModel().getColumn(i);
            column.setCellRenderer(rowRenderer);
        }
        JScrollPane scrollPane = new JScrollPane(table);
        scrollPane.setFont(new Font("Times New Roman", Font.BOLD, 13));
        frame.add(scrollPane);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocation(50, 50);
        frame.pack();
        frame.setVisible(true);
    }

    private class RowColorRenderer extends DefaultTableCellRenderer {

        private static final long serialVersionUID = 1L;
        private int colNo = 0;

        RowColorRenderer(int col) {
            colNo = col;
        }

        @Override
        public Component getTableCellRendererComponent(JTable table, Object value,
                boolean isSelected, boolean hasFocus, int row, int column) {
            Component comp = super.getTableCellRendererComponent(table, value,
                    isSelected, hasFocus, row, column);
            JComponent jc = (JComponent) comp;
            if (!isSelected) {
                if (table.getValueAt(row, colNo) != null) {
                    String str = table.getValueAt(row, colNo).toString();
                    if (!str.isEmpty()) {
                        if ((Pattern.compile("[+]").matcher(str).find())) {
                            setForeground(Color.magenta);
                            setBackground(Color.GREEN);
                            setFont(new Font("Serif", Font.BOLD, 16));
                            setHorizontalAlignment(CENTER);
                        } else if ((Pattern.compile("[-]").matcher(str).find())) {
                            setForeground(Color.blue);
                            setBackground(Color.RED);
                            setFont(new Font("Serif", Font.BOLD, 16));
                            setHorizontalAlignment(CENTER);
                        } else if ((Pattern.compile("[~]").matcher(str).find())) {
                            setForeground(Color.red);
                            setBackground(Color.YELLOW);
                            setFont(new Font("Serif", Font.BOLD, 16));
                            setHorizontalAlignment(CENTER);
                        } else {
                            setBackground(Color.WHITE);
                            setForeground(table.getForeground());
                            setFont(new Font("Serif", Font.PLAIN, 12));
                            setHorizontalAlignment(CENTER);
                        }
                    } else {
                        setBackground(Color.WHITE);
                        setForeground(table.getForeground());
                    }
                }
            }
            return this;
        }
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                Ptf_Viewer frame = new Ptf_Viewer();
            }
        });
    }
}

no need to grab the value from the table because: a) you get it as param b) super already has set it :-) — kleopatra, Jul 31 '13 at 13:56

Jonathan Drapeau · Accepted Answer · 2013-07-31T12:51:52.957

2

You will need to create your own cell renderer and have it return the proper background color depending on the text contained in the cell.

public class MyTableCellRenderer extends DefaultTableCellRenderer {
    @Override
    public Color getBackground() {
        String steak = getText();
        if (steak.startsWith("+")) {
            return Color.GREEN;
        } else if (steak.startsWith("-")) {
            return Color.RED;
        } else if (steak.startsWith("~")) {
            return Color.YELLOW;
        } else if (steak.equals("")) {
            return Color.WHITE;
        }

            return super.getBackground();
        }
    }
}

And make sure your table use it.

table.setDefaultRenderer(String.class, new MyTableCellRenderer());

Assuming here that type of all your cells is String.

Edit after SSCCE : The class is Obejct and not String, use

table.setDefaultRenderer(Object.class, new MyTableCellRenderer());

edited Jul 31 '13 at 12:51

answered Jul 31 '13 at 12:05

Jonathan Drapeau

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beware: this will loose selection visuals – kleopatra Jul 31 '13 at 12:17
I tried to implement this, however it still does not Work, everthing is now White, I also tried to change from getBackground to setBackground, but nothing – abbisDK Jul 31 '13 at 12:25
@abbisDK Then provide a SSCCE. It should work but without all the code, it's impossible to help you more. – Jonathan Drapeau Jul 31 '13 at 12:31
SSCCE made and added to question – abbisDK Jul 31 '13 at 12:46
@abbisDK Shoud work with my latest edit, it does when I test it. – Jonathan Drapeau Jul 31 '13 at 12:53
doubt that you see the blue (in Metal f.i., it's LAF dependent) background if a row is selected, do you? @abbisDK While the renderer is the correct place for custom config, overriding the getter is suboptimal: it's highly brittle, as the coloring is unrelated to cell state (like focused, editable, alternate row coloring, dragging ... whatever the default deems necessary to colorize differently) – kleopatra Jul 31 '13 at 14:00
@kleopatra You're right, it does remove the selection background "marker". – Jonathan Drapeau Jul 31 '13 at 14:16

JTable colors all cells and not only the specific cell

2 Answers2