Coloring Rows of JTables after Initialization

Question

I'm clarifying my earlier problem by providing some sample code

import java.awt.Color;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;

public class TestTable extends javax.swing.JFrame
{
private JButton jButton1;
private JScrollPane jScrollPane1;
private JTable jTable1;

public TestTable()
{
    initComponents();
}

private void initComponents(){

    ///////////////////////////////////////////////
    //Initializing components
    jScrollPane1 = new javax.swing.JScrollPane();
    jTable1 = new javax.swing.JTable();
    jButton1 = new javax.swing.JButton();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    String data[][] = { {"A","B","C"},
                        {"R","S","T"},
                        {"U","V","W"}
                      };
    String col[] = {"X","Y","Z"};
    jTable1 = new JTable(new DefaultTableModel(data, col));
    jScrollPane1.setViewportView(jTable1);

    jButton1.setText("jButton1");

    ///////////////////////////////////////////////
    //positioning button and table
    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap(15, Short.MAX_VALUE)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 375,     javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addContainerGap())
                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                    .addComponent(jButton1)
                    .addGap(160, 160, 160))))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 117,     javax.swing.GroupLayout.PREFERRED_SIZE)
            .addGap(47, 47, 47)
            .addComponent(jButton1)
            .addContainerGap(102, Short.MAX_VALUE))
    );

    ///////////////////////////////////////////////
    //create event callback for the button
    jButton1.setText("Change data & color");
    jButton1.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jButton1ActionPerformed(evt);
        }
    });

    ///////////////////////////////////////////////
    pack();
}


private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {

    //change the data in the table
    String data[][] = { {"a","b","c"},
                        {"r","s","t"},
                        {"u","v","w"}  };
    String col[] = {"x","y","z"};
    DefaultTableModel model= new DefaultTableModel(data,col);
    jTable1.setModel(model);

    //change the header in the table
    jTable1.getTableHeader().setBackground(Color.red);

    // IS IT POSSIBLE TO INSERT CODE HERE, WITHOUT REINITIALIZING jTable1,
    // SO THAT CLICKING THE BUTTON WILL TURN THE MIDDLE ROW GREEN?


    //change button text
    jButton1.setText("Changed");
}


public static void main(String[] args) 
{
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
            new TestTable().setVisible(true);
        }
    });

}

}

I've been able to change the colors of the rows when I run TestTable in main, but I am having problems with changing the rows colors from within a callback (as above). My guess was to insert code like

jTable1.getCellRenderer(0, 0).getTableCellRendererComponent(jTable1, String.class, false,false,     0,0).setBackground(Color.green);

Since I am specifying entry (0,0) of the table in this code, I would expect that this code would turn entry (0,0), however, this turns the entire table green! Note, I can change the data in the model and the color of the header without any problems.

Any help sincerely appreciated. Thanks Chris

score 4 · Answer 1 · answered Aug 07 '12 at 15:58

Here is an example on how you can combine both column colors and row color. You basically perform tests in the TableCellRenderer to see if the background should be of one color or another.

import java.awt.Color;
import java.awt.Component;
import java.util.Enumeration;
import java.util.Vector;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;

public class TestTable {

    public class MyTableCellRenderer extends DefaultTableCellRenderer implements TableCellRenderer {
    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
        setBackground(null);
        super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
        setText(String.valueOf(value));
        boolean interestingRow = row % 5 == 2;
        boolean secondColumn = column == 1;
        if (interestingRow && secondColumn) {
            setBackground(Color.ORANGE);
        } else if (interestingRow) {
            setBackground(Color.YELLOW);
        } else if (secondColumn) {
            setBackground(Color.RED);
        }
        return this;
    }

}

private JFrame f;
private JTable table;

protected void initUI() {
    Vector<Vector<Object>> data = new Vector<Vector<Object>>();
    Vector<String> columNames = new Vector<String>();
    columNames.add("Col 0");
    columNames.add("Col 1");
    columNames.add("Col 2");
    for (int i = 0; i < 20; i++) {
        Vector<Object> v = new Vector<Object>();
        v.add(i % 3 == 0 ? "Hello" : "World");
        v.add("Some data in row " + (i + 1));
        v.add("Some other data in row " + (i + 1));
        data.add(v);
    }
    table = new JTable(new DefaultTableModel(data, columNames));
    Enumeration<TableColumn> en = table.getColumnModel().getColumns();
    while (en.hasMoreElements()) {
        TableColumn tc = en.nextElement();
        tc.setCellRenderer(new MyTableCellRenderer());
    }
    f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setLocationRelativeTo(null);
    f.add(new JScrollPane(table));
    f.pack();
    f.setVisible(true);

}

public static void main(String[] args) {

    SwingUtilities.invokeLater(new Runnable() {

        @Override
        public void run() {
            new TestTable().initUI();
        }
    });
}

}

Thanks for this. I think I have been able to create similar successful code similar to this. The problem I've been having is to render from a callback, using the already initialised jTable. I have edited my original query and created some example code, which is complete, except for the code that ought to be put into the callback. I would be grateful if you have any further ideas and you'd be willing to share them. Thanks again. — Chris W, Aug 07 '12 at 19:40
Hi, I have completely revised my example code to make it clear where the problem seems to be. I have looked at the TableDialogEditDemo in docs.oracle, and this allows me to change the color, but only if the object type of the cell is a color (not a string as here). — Chris W, Aug 08 '12 at 12:02

mKorbel · Answer 2 · 2012-08-07T15:31:13.747

2

update TableModel, do not create a new JTable, then you have to add Renderer to new JTable too
updates must be done on Event Dispatch Thread, otherwise any changes will not be visible in the GUI or you get Exception from RepaintManager
all changes from DefaultTableModel to the JTables view are done automatically and used prepareRenderer should be repainted all rows too,

edited Aug 07 '12 at 15:31

answered Aug 07 '12 at 15:25

mKorbel

109,525
20
134
319

Hi, I am unclear about your first point- could you explain a little more for me please? - I am updating the table model in my method, using jTable1.setModel(newModel). You said that Renderer must be added to the new JTable, but isn't this what we want to avoid (ie a new JTable)? I'm also confused because in the first part of the sentence, you say do not create a new JTable. I would like to change the backcolor of different rows in my jTable1 from my menu callback. Thanks – Chris W Aug 07 '12 at 15:56
JTable, its Model and prepareRenderer should be create once time, only – mKorbel Aug 07 '12 at 16:09

score 0 · Accepted Answer · answered Aug 08 '12 at 14:54

Using a TableCellRenderer is still what you want even with your updated question (as @Ryan said). You're just going to want to put in some special code to indicate what rows you want specially colored. Here's an example (using your test code):

import java.awt.Color;
import java.awt.Component;
import java.util.HashMap;

import javax.swing.*;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;

public class TestTable extends javax.swing.JFrame
{
    private JButton jButton1;
    private JScrollPane jScrollPane1;
    private JTable jTable1;
    private CustomRenderer renderer;

    public TestTable()
    {
        initComponents();
    }

    private void initComponents(){

        ///////////////////////////////////////////////
        //Initializing components
        jScrollPane1 = new javax.swing.JScrollPane();
        jTable1 = new javax.swing.JTable();
        jButton1 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        String data[][] = { {"A","B","C"},
                {"R","S","T"},
                {"U","V","W"}
        };
        String col[] = {"X","Y","Z"};
        jTable1 = new JTable(new DefaultTableModel(data, col));
        //Setup Renderer
        renderer = new CustomRenderer();
        //Add Renderer to table
        jTable1.getColumnModel().getColumn(0).setCellRenderer(renderer);
        jTable1.getColumnModel().getColumn(1).setCellRenderer(renderer);
        jTable1.getColumnModel().getColumn(2).setCellRenderer(renderer);

        jScrollPane1.setViewportView(jTable1);

        jButton1.setText("jButton1");

        ///////////////////////////////////////////////
        //positioning button and table
        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                        .addContainerGap(15, Short.MAX_VALUE)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                                .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                                        .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 375,     javax.swing.GroupLayout.PREFERRED_SIZE)
                                        .addContainerGap())
                                        .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                                                .addComponent(jButton1)
                                                .addGap(160, 160, 160))))
        );
        layout.setVerticalGroup(
                layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                        .addContainerGap()
                        .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 117,     javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(47, 47, 47)
                        .addComponent(jButton1)
                        .addContainerGap(102, Short.MAX_VALUE))
        );

        ///////////////////////////////////////////////
        //create event callback for the button
        jButton1.setText("Change data & color");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        ///////////////////////////////////////////////
        pack();
    }


    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {



        DefaultTableModel model= (DefaultTableModel)jTable1.getModel();
        //change the data in the table
        String data[][] = { {"a","b","c"},
                {"r","s","t"},
                {"u","v","w"}  };
        String col[] = {"x","y","z"};
        model.setDataVector(data, col);

        // Necessary to re-add listener (because we're creating new columns) 
        jTable1.getColumnModel().getColumn(0).setCellRenderer(renderer);
        jTable1.getColumnModel().getColumn(1).setCellRenderer(renderer);
        jTable1.getColumnModel().getColumn(2).setCellRenderer(renderer);

        //change the header in the table
        jTable1.getTableHeader().setBackground(Color.red);


        // IS IT POSSIBLE TO INSERT CODE HERE, WITHOUT REINITIALIZING jTable1,
        // SO THAT CLICKING THE BUTTON WILL TURN THE MIDDLE ROW GREEN?
        renderer.colorModel.put(1, Color.green); //Yes

        //change button text
        jButton1.setText("Changed");
    }


    public static void main(String[] args) 
    {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new TestTable().setVisible(true);
            }
        });

    }

    //Custom Renderer - does the default rendering except if told the row should be a different color
    public static class CustomRenderer extends DefaultTableCellRenderer{

        //Stores what color you want for rows
        public HashMap<Integer, Color> colorModel = new HashMap<Integer, Color>();

        @Override
        public Component getTableCellRendererComponent(JTable table,
                Object value, boolean isSelected, boolean hasFocus, int row,
                int column) {
            //Default Rendering
            Component result = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

            //Change color of background (If necessary)
            if(colorModel.get(row) != null){
                setBackground(colorModel.get(row));
            } else if(!isSelected){
                setBackground(null);
            }
            return result;
        }

    }
}

score 0 · Answer 4 · answered Aug 08 '12 at 15:04

0

Thanks Nick.

After scanning through the methods, I found an easy way to highlight the rows I wanted by selecting them then coloring the selection

    jTable1.setRowSelectionInterval(0, 1);
    jTable1.setSelectionBackground(Color.black);

answered Aug 08 '12 at 15:04

Chris W

145
1
2
12

I suppose that may work in your case - so long as you don't mind that any future selection the user makes will turn the table row that color as well. Finding an answer to your own question is somthing to be proud of - congrats! – Nick Rippe Aug 08 '12 at 15:17

Coloring Rows of JTables after Initialization

4 Answers4