Appending a new row to a JTable at runtime

[Nation]

I am developing a Java application that uses a JTable. I want to allow the user to enter data in a JTable that can later be printed or saved as PDF file. The issues is: Suppose the user has entered some data and the cursor is on the last cell of the row in a table (I have uploaded an image-suppose the cursor is on the highlighted cell).How do I make it in such a way that when a user presses the Enter Button(Keyboard button) the application will add/append a new row that is empty to the table so that the user can fill in other data.

[JamesCherrill]

Which part of that is the problem? Responding to the enter button, adding a blank row to a table, or something else?

[Nation]

Hie James,
The problem is adding a new row to the table. The row should be part of the table not a stand alone. What should I include to make it work that way?

[JamesCherrill]

Here's the trick:
JTable is just a view, the actual structure and data is in its TableModel.
Get your JTable's TableModel (DefaultTableModel) myTable.getModel(), and add a new row to that addRow(Object[] data)

[Nation]

Hie James,

I have created a listener that will listen to table changes as follows:

    public void createTable(){
    table= new JTable(data,colNames);
    sp= new JScrollPane(table);
    table.getModel().addTableModelListener(new TableModelListener() {

        @Override
        public void tableChanged(TableModelEvent tme) {
            //my code for adding a new row has to go here
            table.getModel().//this line is giving me an error.
        }
    });

i have tried the following and it is giving me an error - i mean i cant see the getTableModel method.

    model = JTableObj.getTableModel();
    model.insertRow(table.getRowCount(),new Object[] {"","","","",""});

How do I resolve this? thanks in advance for yor help.

[JamesCherrill]

As in my previous post: It's getModel, not getTableModel, and you have to cast the returned value to (DefaultTableModel) because thats where the addRow method is. (Unless, of course, you have defined your own TableModel.)

[Nation]

Hie James,

Thanks for the idea.I casted it as follows:

  TableModel tm=table.getModel();
           DefaultTableModel dtm=(DefaultTableModel)tm;
           dtm.addRow(newRow);

The problem is it is giving this error:

Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: javax.swing.JTable$1 cannot be cast to javax.swing.table.DefaultTableModel
    at JTableDemo$1.tableChanged(JTableDemo.java:48)
    at javax.swing.table.AbstractTableModel.fireTableChanged(AbstractTableModel.java:296)
    at javax.swing.table.AbstractTableModel.fireTableCellUpdated(AbstractTableModel.java:275)
    at javax.swing.JTable$1.setValueAt(JTable.java:694)
    at javax.swing.JTable.setValueAt(JTable.java:2741)
    at javax.swing.JTable.editingStopped(JTable.java:4723)
    at javax.swing.AbstractCellEditor.fireEditingStopped(AbstractCellEditor.java:141)
    at javax.swing.DefaultCellEditor$EditorDelegate.stopCellEditing(DefaultCellEditor.java:368)
    at javax.swing.DefaultCellEditor.stopCellEditing(DefaultCellEditor.java:233)
    at javax.swing.JTable$GenericEditor.stopCellEditing(JTable.java:5480)
    at javax.swing.DefaultCellEditor$EditorDelegate.actionPerformed(DefaultCellEditor.java:385)
    at javax.swing.JTextField.fireActionPerformed(JTextField.java:508)
    at javax.swing.JTextField.postActionEvent(JTextField.java:721)
    at javax.swing.JTextField$NotifyAction.actionPerformed(JTextField.java:836)
    at javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1664)
    at javax.swing.JComponent.processKeyBinding(JComponent.java:2878)
    at javax.swing.JComponent.processKeyBindings(JComponent.java:2925)
    at javax.swing.JComponent.processKeyEvent(JComponent.java:2841)
    at java.awt.Component.processEvent(Component.java:6282)
    at java.awt.Container.processEvent(Container.java:2229)
    at java.awt.Component.dispatchEventImpl(Component.java:4861)
    at java.awt.Container.dispatchEventImpl(Container.java:2287)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1895)
    at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:762)
    at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1027)
    at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:899)
    at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:727)
    at java.awt.Component.dispatchEventImpl(Component.java:4731)
    at java.awt.Container.dispatchEventImpl(Container.java:2287)
    at java.awt.Window.dispatchEventImpl(Window.java:2719)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:735)
    at java.awt.EventQueue.access$200(EventQueue.java:103)
    at java.awt.EventQueue$3.run(EventQueue.java:694)
    at java.awt.EventQueue$3.run(EventQueue.java:692)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
    at java.awt.EventQueue$4.run(EventQueue.java:708)
    at java.awt.EventQueue$4.run(EventQueue.java:706)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:705)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)

Is it the right listener that i used?

Here is my whole code if it can help:

public final class JTableDemo extends JFrame {

    String[] colNames = {"Name", "Surname"};
    String[][] data = {{"Nation", "Chirara"}, {"Bill", "Thompson"}};
    String [][] newRow={{"",""},{"",""}};
    JTable table;
    JScrollPane sp;

    JTableDemo(String title){
    super(title);
    this.setSize(300, 300);
    this.setVisible(true);

    Container con= this.getContentPane();
    this.createTable();
    con.add(sp);


    }
    public void createTable(){
    table= new JTable(data,colNames);
    sp= new JScrollPane(table);
    table.getModel().addTableModelListener(new TableModelListener() {

        @Override
        public void tableChanged(TableModelEvent tme) {

           TableModel tm=table.getModel();
           DefaultTableModel dtm=(DefaultTableModel)tm;
           dtm.addRow(newRow);
        }
    });


    }
    public static void main(String [] args){
    JTableDemo jtd= new JTableDemo("My Table");

    }

}

Please advise me where i have gone wrong. I want it to work in such a way that when i hit the Keyboard Enter button, it appends a new row that is empty to the existing table. thanks for ideas once again.

[Nation]

i have added an image of my output. i want it to work in such that when i press the enter button with the focus on the last cell as shown in the output image....it should append a new empty row.

[JamesCherrill]

You're getting that error because the constructor you used to create your JTable is a simple one that doesn't build a TabelModel that supports adding rows.

DefaultTableModel is the obvious first choice. To get a DefaultTableModel you simply ask for one, ie

DefaultTableModel tm = new DefaultTableModel(data, colNames);
table= new JTable(tm);

now you have a JTable with a TableModel that supports adding rows.

Setting up the event handler to add the row at the right time is a different problem, but ... one step at a time

[Nation]

Hie James,

Thanks very much for your help. I really appreciate your patience with me.
I did what you suggested and it worked perfect.

Now I have a different problem. let me close this thread and start a new one.