JLabel as cell of JTable

Hi All,
I am using JLabel as a cell of a JTable by overriding getTableCellRendererComponent method of the renderer.But I am not able to select/focus on any of the cell by clicking at cells.However If I use any other componenet like JTextArea, I can select any cell I want.
I have to use JLabel because i want to put multiple color and fonts in a single cell.I dont't want to use JTextPane because it takes more memory as well as It has wraping problem
Any help would be greatly appreciated

It's not a good idea to create a NEW Component each and every time getXXXCellRenderer() is called. Object creation is VERY expensive!!!
Remember, this Component is merely renderered (e.g. painted, or "rubber-stamped") into the Graphics Context of the JTable, after appropriate sizing to fit the cell, of course. So the SAME component can be used to render each and every cell, each and every time each cell needs to be rendered. (Unless different Component classes are used to render different cells, but still, one of each of these Components should be created in the Constructor, not each time a cell is rendered.)
I have reworked your code to make it much more efficient, and to make it more readable:
public class MyTableCellRenderer
    implements TableCellRenderer
    JLabel label = new JLabel();
    public MyTableCellRenderer()
        super();
        this.label.setOpaque(true);
    public Component getTableCellRendererComponent( JTable table,
                                                    Object value,
                                                    boolean isSelected,
                                                    boolean hasFocus,
                                                    int     row,
                                                    int     column )
        String st=null;
        st="<HTML><B><FONT Color=Red>" + value.toString()
           + "</FONT></B></HTML>";
        this.label.setText(st);
        if (isSelected) {
            this.label.setBackground( table.getSelectionBackground());
        } else {
            this.label.setBackground(Color.yellow);
        return this.label;
}You may find that using HTML as the text of JLabel is much too expensive, especially with a large table. I tried it once, with a table of only moderate size, and gave up. It's much faster to set the font, foreground color, etc., on the JLabel itself instead.
I was trying to use HTML simply to get HTML Character Entities (like &) to display correctly, and it just didn't work. I wrote my own class to parse strings for HTML Character Entities, replacing them with appropriate Unicode characters, and it worked much better.
---Mark

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hi!
Actually i want to change the background color of few cells in JTable
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i want to change the background color of few cells in JTableDepending on your requirements for the coloring of cells it may be easier to override the prepareRenderer() method of JTable:
http://forum.java.sun.com/thread.jspa?forumID=57&threadID=610474

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Hi all,
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Thx

You could create your own renderer or you could try something like:
table = new JTable(model)
     public TableCellRenderer getCellRenderer(int row, int column)
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Hi, can i know how to set the focus to a particular cell in JTable.
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OK. It's partially working. The right methods to use are setRowSelectionInterval and setColumnSelectionInterval. Jeanette was right. Mine didn't work because of a thread issue. I put the those two methods in a block such as:
SwingUtilities.invokeLater(new Runnable(){
public void run()
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But after I finished editing the first cell of the newly created row and press ENTER, the selection went back to the cell that's next to the originally editing cell on the first(old) row, instead of staying at the current row and going to the second cell.
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I having a problem on how to set disable a particular cell in JTable. At the first place to load the JTable, I want to set some of the cell to disabled, it only will run at the first time, is there anyway to do it ?

This is the function that disable/enable cells in JTables.
Are you looking for this?
public boolean isCellEditable(int row, int col)
if(((new Integer((String)(getValueAt(row,0)).toString()).intValue()>9))&&(col==1))
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if(row!=4&&col!=5)
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Hi,
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Thanks
Subbu

Thanks for all replies. Now, i am able to edit the cell on single click.

What component is placed default in each cell of JTable?

Hi,
What component is placed default in each cell of JTable?

It depends on the content, see How to Use Tables - Concepts: Editors and Renderers for details.

Problem with select all cells in JTable

Hi guys! I get some problem about selecting all cells in JTable. I tried to used two methods:
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Note: i set up the selection model as following:
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What selection properity should be changed in order to enable selectAll() method work properly? Is there Any constraints? Here is the TableModel I am using. And i set up selection mode use the following code:
table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
table.setCellSelectionEnabled(true);
table.setRowSelectionAllowed(true);
table.setColumnSelectionAllowed(true);
import java.util.Vector;
import javax.swing.table.*;
import javax.swing.JTable;
public class DataSheetModel extends AbstractTableModel{
          private Vector data = new Vector();//Store data
          private Vector columnNames = new Vector();//Store head
          public DataSheetModel(){}
          public DataSheetModel(Vector headVector, Vector dataVector){
               if(headVector != null) this.columnNames = headVector;
               if(dataVector != null) this.data = dataVector;
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               return columnNames.size()+1;
          public int getRowCount(){
               return data.size()+1;
          public String getColumnName(int col){
               if(col==0) return "";
               else return (String)columnNames.get(col-1);
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               if(col==0) {
                    if(row != data.size()) return String.valueOf(row);
                    else return "*";
               else{
                    if(row != data.size()){
                         Vector rowVector = (Vector)data.elementAt(row);
                         return rowVector.elementAt(col-1);
                    }else return null;
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               if(row != this.data.size()){
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               return getValueAt(0,c).getClass();
          public boolean isCellEditable(int row, int col){
               if(col == 0) return false;
               else return true;
          public void setDataVector(Vector head, Vector data){
               if(head != null) this.columnNames = head;
               if(data != null) this.data = data;
}

Merge cells in JTable.......

Plz some help me out ......i want to merge two consecutive cells of a row in one cell in JTable......... how to do that.....give some code if possible....

Well, as a new member you should learn to search the forum first before posting questions. Using keywords like "jtable merge cell" will find other postings on this topic. Some with solutions some without, so you will need to read a few and decide on the approach you want to take.

Aligning the Text in Centre for MultiLine Cells in JTable

Hi;
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Any ideas?
Kindly to provide me a solution for this its urgent.

Hi;
Thanks for the reply,on using Text Area as renderer i.e using Multi-Line cells in JTable, i achieved the objective of displaying the text on multiple lines in the cell."In my Table there are 5 columns and i'm setting renderer on 3rd and 5th column,If the text is too large in column 5 it automatically gets wrapped off for all the cells in column 5.For column 3 my text is not so large as compared to column 5 and due to which the Text in the column 3 starts from the top for all the cells i.e (the first row in column 3 is parallel to first row in column 5 ),Now the problem is i can't display the text in the center of all cells for Column 3 .
Thanks in advance

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hello experts!!
how can i center(horizontal) position/left/right justified a text in a cell in JTable?
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kagaw3000 wrote:
ok i got it!
But i am really confuse in JTable tutorial. it uses JLable as a CellRenderer and JButton as a CellEditor
then it returns a Color.
for clarification, when i am editing a cell, CellEditor will takes place, right? and when customizing the display of a cell, CellRendere will takes place, right?
There is a very good explanation at the beginning of the Concepts: Editors and Renderers section in the tutorial.
can you show me code that get and return a String not a Color.class?The default editor GenericEditor of JTable uses a JTextField which returns a String:
static class GenericEditor extends DefaultCellEditor {
    Class[] argTypes = new Class[]{String.class};
    java.lang.reflect.Constructor constructor;
    Object value;
    public GenericEditor() {
        super(new JTextField());
        getComponent().setName("Table.editor");
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        String s = (String)super.getCellEditorValue();
        // Here we are dealing with the case where a user
        // has deleted the string value in a cell, possibly
        // after a failed validation. Return null, so that
        // they have the option to replace the value with
        // null or use escape to restore the original.
        // For Strings, return "" for backward compatibility.
        if ("".equals(s)) {
            if (constructor.getDeclaringClass() == String.class) {
                value = s;
            super.stopCellEditing();
        try {
            value = constructor.newInstance(new Object[]{s});
        catch (Exception e) {
            ((JComponent)getComponent()).setBorder(new LineBorder(Color.red));
            return false;
        return super.stopCellEditing();
    public Component getTableCellEditorComponent(JTable table, Object value,
            boolean isSelected,
            int row, int column) {
        this.value = null;
        ((JComponent)getComponent()).setBorder(new LineBorder(Color.black));
        try {
            Class type = table.getColumnClass(column);
            // Since our obligation is to produce a value which is
            // assignable for the required type it is OK to use the
            // String constructor for columns which are declared
            // to contain Objects. A String is an Object.
            if (type == Object.class) {
                type = String.class;
            constructor = type.getConstructor(argTypes);
        catch (Exception e) {
            return null;
        return super.getTableCellEditorComponent(table, value, isSelected, row, column);
    public Object getCellEditorValue() {
        return value;
}

How do i do that? MultiLine in a cell of JTable !!!

Dear friends,
I am trying to add multiline in a cell of JTable. For that bellow code i have written, but my statement in cell displays in a line only. Code is given bellow (copy/paste/run), could anyone help me how to do that?
Regards..
Jaya.
import javax.swing.JTable;
import javax.swing.table.AbstractTableModel;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.JOptionPane;
import java.awt.*;
import java.awt.event.*;
import javax.swing.border.*;
import javax.swing.table.*;
import java.sql.*;
public class OtL extends JFrame {
    public OtL()
      initComponents();
    private void initComponents() {
        model1 = new DefaultTableModel();
        btnClose = new javax.swing.JButton();
        tblOt       = new javax.swing.JTable(model1);
        scrOt   = new javax.swing.JScrollPane();
        TableCellRenderer renderer = new TableRenderer();
        tblOt.setDefaultRenderer(Object.class,renderer);
        tblOt.setRowHeight(tblOt.getRowHeight()*3);
        tblOt.setBackground(new java.awt.Color(250,225,162));
        getContentPane().setLayout(null);
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                exitForm(evt);
        btnClose.setText("CLOSE");
        btnClose.setToolTipText("Close This Screen");
        btnClose.setBorder(new javax.swing.border.BevelBorder(javax.swing.border.BevelBorder.RAISED));
        btnClose.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
              System.exit(0);
        getContentPane().add(btnClose);
        btnClose.setBounds(380, 470, 110, 25);
        tblOt.setToolTipText("Operation Theatre Booking List");
        scrOt.setViewportView(tblOt);
        tableSize();
        scrOt.setBorder(new javax.swing.border.LineBorder(new java.awt.Color(0, 0, 0)));
        scrOt.setToolTipText("Operation Theatre Booking List");
        getContentPane().add(scrOt);
        scrOt.setBounds(15, 150, 770, 300);
        displayOtList();
    private void exitForm(java.awt.event.WindowEvent evt) {
        System.exit(0);
    public static void main(String args[]) {
        JFrame j = new OtL();
        j.setSize(800,560);
        j.show();
/**********Code for displaying Operation Theater Booking List****Start Here*************/
    public void displayOtList(){
Here i fire a sql query and i populate data in table.
Sometime i get more than 1 value for some column e.g Surgery Name and Surgeon Name, so
i want to display more than 1 value in the same cell. like bellow i have mentiond for
5th and 6th column. But its displayin in one line only, how can i display that in multiple line!!
I know that can be taken care with Renderer, i tried but couldn't go through. I have written TableRenderer
class for that, please help me what should i do in Renderer class.
      int row1=0;
      tableSize();
      DefaultTableModel model1 = (DefaultTableModel)tblOt.getModel();
      Object[] newRow = new Object[6];
        for(int i=0;i<1;i++){
          row1 = tblOt.getRowCount() + 1;
          newRow[0] = "1";
          newRow[1] = "10:10";
          newRow[2] = "11:30";
          newRow[3] = "Name Here";
          newRow[4] = "Surgery Name1 \n Surgery Name2";
          newRow[5] = "Dr. Amit \n Dr. Johnson";
          model1.addRow(newRow);
/**********Code for displaying Operation Theater Booking List****End Here*************/
   class TableRenderer extends DefaultTableCellRenderer{
     public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean
hasFocus, int row, int column)
       super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
      setOpaque(true);
       return this;
/******tableSize()*****code for sizing table******start here()********/
public void tableSize(){
    tblOt.setModel(new javax.swing.table.DefaultTableModel(
        new Object [][] {},
        new String [] {"Ot No.", "Start Time","End Time", "Patient Name", "Surgery Name","Surgeon Name"}
    TableColumn column = null;
    for (int i = 0; i < 6; i++) {
      column = tblOt.getColumnModel().getColumn(i);
      if (i == 0) {
        column.setPreferredWidth(5);
      if (i == 1) {
        column.setPreferredWidth(15);
      if (i == 2) {
      column.setPreferredWidth(15);
      if (i == 3) {
        column.setPreferredWidth(130);
      if (i == 4) {
        column.setPreferredWidth(130);
      if (i == 5) {
        column.setPreferredWidth(130);
/******tableSize()*****code for sizing table******end here()********/
    private javax.swing.JButton btnClose;
    private javax.swing.JScrollPane scrOt;
    private javax.swing.JTable tblOt;
    private DefaultTableModel model1;
[\code]

OK Filne, Thanx .. its displaying data in multiple line now.
But still there is a problem, whenever i move mouse over the table row it returns error like bellow. I am not able to findout the reason of error. I tried to put code in try{} catch{} block to avoid this error, but still its coming. Help me.....!!!!!!!!
java.lang.NullPointerException
        at javax.swing.text.View.getViewIndex(View.java:1060)
        at javax.swing.text.View.getToolTipText(View.java:1031)
        at javax.swing.plaf.basic.BasicTextUI.getToolTipText(BasicTextUI.java:1057)
        at javax.swing.text.JTextComponent.getToolTipText(JTextComponent.java:1533)
        at javax.swing.JTable.getToolTipText(JTable.java:2380)
        at javax.swing.ToolTipManager$insideTimerAction.actionPerformed(ToolTipManager.java:669)
        at javax.swing.Timer.fireActionPerformed(Timer.java:256)
        at javax.swing.Timer$DoPostEvent.run(Timer.java:190)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:167)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:437)
        at java.awt.EventDispatchThread.pumpOneEvent(EventDispatchThread.java:150)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:136)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:131)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:99)my latest programe code is here :
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.border.*;
import javax.swing.table.*;
public class OtL extends JFrame {
    public OtL()
      initComponents();
    private void initComponents() {
        model1 = new DefaultTableModel();
        btnClose = new javax.swing.JButton();
        tblOt       = new javax.swing.JTable(model1);
        scrOt   = new javax.swing.JScrollPane();
        TableCellRenderer renderer = new TableRenderer();
        tblOt.setDefaultRenderer(Object.class,renderer);
        tblOt.setRowHeight(tblOt.getRowHeight()*3);
        tblOt.setBackground(new java.awt.Color(250,225,162));
        getContentPane().setLayout(null);
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                exitForm(evt);
        btnClose.setText("CLOSE");
        btnClose.setBorder(new javax.swing.border.BevelBorder(javax.swing.border.BevelBorder.RAISED));
        btnClose.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
              System.exit(0);
        getContentPane().add(btnClose);
        btnClose.setBounds(380, 470, 110, 25);
        scrOt.setViewportView(tblOt);
        tableSize();
        scrOt.setBorder(new javax.swing.border.LineBorder(new java.awt.Color(0, 0, 0)));
        getContentPane().add(scrOt);
        scrOt.setBounds(15, 150, 770, 300);
        displayOtList();
    private void exitForm(java.awt.event.WindowEvent evt) {
        System.exit(0);
    public static void main(String args[]) {
        JFrame j = new OtL();
        j.setSize(800,560);
        j.show();
    public void displayOtList(){
      int row1=0;
      tableSize();
      DefaultTableModel model1 = (DefaultTableModel)tblOt.getModel();
      Object[] newRow = new Object[6];
        for(int i=0;i<1;i++){
          row1 = tblOt.getRowCount() + 1;
          newRow[0] = "1";
          newRow[1] = "10:10";
          newRow[2] = "11:30";
          newRow[3] = "Name Here";
          newRow[4] = "Surgery Name1 \n Surgery Name2";
          newRow[5] = "Dr. Amit \n Dr. Johnson";
          model1.addRow(newRow);
   class TableRenderer extends JTextArea implements TableCellRenderer{
      public TableRenderer(){
        setLineWrap(true);
        setWrapStyleWord(true);
        setOpaque(true);
     public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean
hasFocus, int row, int column)
      if (isSelected) {
        setForeground(tblOt.getSelectionForeground());
        setBackground(tblOt.getSelectionBackground());
      } else {
        setForeground(tblOt.getForeground());
      setFont(tblOt.getFont());
      if (hasFocus) {
        setBorder( UIManager.getBorder("Table.focusCellHighlightBorder") );
          if (tblOt.isCellEditable(row, column)) {
            setForeground( UIManager.getColor("Table.focusCellForeground") );
            setBackground( UIManager.getColor("Table.focusCellBackground") );
          } else {
        setBorder(new EmptyBorder(1, 2, 1, 2));
      setText((value == null) ? "" : value.toString());
      return this;
/******tableSize()*****code for sizing table******start here()********/
public void tableSize(){
    tblOt.setModel(new javax.swing.table.DefaultTableModel(
        new Object [][] {},
        new String [] {"Ot No.", "Start Time","End Time", "Patient Name", "Surgery Name","Surgeon Name"}
    TableColumn column = null;
    for (int i = 0; i < 6; i++) {
      column = tblOt.getColumnModel().getColumn(i);
      if (i == 0) {
        column.setPreferredWidth(5);
      if (i == 1) {
        column.setPreferredWidth(15);
      if (i == 2) {
      column.setPreferredWidth(15);
      if (i == 3) {
        column.setPreferredWidth(130);
      if (i == 4) {
        column.setPreferredWidth(130);
      if (i == 5) {
        column.setPreferredWidth(130);
/******tableSize()*****code for sizing table******end here()********/
    private javax.swing.JButton btnClose;
    private javax.swing.JScrollPane scrOt;
    private javax.swing.JTable tblOt;
    private DefaultTableModel model1;
}

Merge table cells of JTable

Can we merge two cells of JTable, the way we do it in html using rowspan and colspan?

no, that's unsupported. There are some (partly oldish, google should help) experiments out there - but beware: they all require tweaks on the level of the ui-delegates which isn't a real option most of the time.
Cheers
Jeanette

Merging Cells in JTable

I want to merge cells of JTable. I searched on net about this and found that there is no direct API available for doing this.
After visiting many forums I found that jp.gr.java_conf.tame.swing.table package is needed to merge cells. Where will I get this package from and is this package for free? Other packages for merging cells will also do.
Thanks in advance

Pranav_Tipnis wrote:
I found that jp.gr.java_conf.tame.swing.table package is needed to merge cells. Where will I get this package from and is this package for free? Yes, this package is for free. You get it from here: [http://www.codeguru.com/java/articles/137_tame1.zip]
However, the component is complicated and difficult to adapt and debug in case you need special functionality.

JLabel as cell of JTable

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