Thread: Jtable only updates at the end of a buton event.

My problem is the following :

I have a jtable that displays some data in the rows.
I have a button whose event is to loop slowly through the rows of this table and change the values of the data - in this case flip true/false .. and slowly is due to a sleep (The actual problem I have is a lengthy calculation)
I would like the table to update after each change, as it currently only updates at the end of the button event.
What am i doing wrong ? I have tried all sorts of combinations.


The (self contained) code that demonstrates the problem is below -
I have adapted the TableDemo example for the orcale/java How to Use Tables tutorial

  /** * TableDemo is just like SimpleTableDemo, except that it * uses a custom TableModel. */ public class TableDemo extends JPanel {   private JButton looper; JTable table; MyTableModel mdl; private static JFrame frame;   public TableDemo() { super(new GridLayout(2,0));   looper = new JButton(); looper.setText("Hit Me to loop thru table and flip vegetarian preference");   looper.addActionListener(new java.awt.event.ActionListener() { @Override public void actionPerformed(java.awt.event.ActionEvent evt) { HitButtonActionPerformed(evt); } });   mdl = new MyTableModel(); table = new JTable(mdl); table.setPreferredScrollableViewportSize(new Dimension(500, 70)); table.setFillsViewportHeight(true);   //Create the scroll pane and add the table to it. JScrollPane scrollPane = new JScrollPane(table);   //Add the scroll pane to this panel. add(scrollPane); //add button add(looper); }   public void HitButtonActionPerformed(ActionEvent e) {   for (int row=0; row<table.getRowCount();row++) { try { Thread.currentThread().sleep(1000);//sleep for 1000 ms System.out.println("one more flip");   Object p = table.getValueAt(row, 4); table.setValueAt( !((Boolean)p), row, 4);   /* no hope ( (AbstractTableModel)table.getModel()).fireTableCellUpdated(row, 4); mdl.fireTableCellUpdated(row, 4); mdl.fireTableDataChanged(); table.validate(); frame.repaint(); */   } catch (InterruptedException ex) { Logger.getLogger(TableDemo.class.getName()).log(Level.SEVERE, null, ex); }   } }   class MyTableModel extends AbstractTableModel { private String[] columnNames = {"First Name", "Last Name", "Sport", "# of Years", "Vegetarian"}; private Object[][] data = { {"Kathy", "Smith","Snowboarding", new Integer(5), false}, {"John", "Doe","Rowing", new Integer(3), true}, {"Sue", "Black", "Knitting", new Integer(2), false}, {"Jane", "White", "Speed reading", new Integer(20), true}, {"Joe", "Brown","Pool", new Integer(10), false} };   @Override public int getColumnCount() { return columnNames.length; }   @Override public int getRowCount() { return data.length; }   @Override public String getColumnName(int col) { return columnNames[col]; }   @Override public Object getValueAt(int row, int col) { return data[row][col]; }   /* * JTable uses this method to determine the default renderer/ * editor for each cell. If we didn't implement this method, * then the last column would contain text ("true"/"false"), * rather than a check box. */ @Override public Class getColumnClass(int c) { return getValueAt(0, c).getClass(); }   /* * Don't need to implement this method unless your table's * editable. */ @Override public boolean isCellEditable(int row, int col) { //Note that the data/cell address is constant, //no matter where the cell appears onscreen. if (col < 2) { return false; } else { return true; } }   /* * Don't need to implement this method unless your table's * data can change. */ @Override public void setValueAt(Object value, int row, int col) { data[row][col] = value; fireTableCellUpdated(row, col); } }   /** * Create the GUI and show it. For thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createAndShowGUI() { //Create and set up the window. frame = new JFrame("TableDemo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);   //Create and set up the content pane. TableDemo newContentPane = new TableDemo(); newContentPane.setOpaque(true); //content panes must be opaque frame.setContentPane(newContentPane);   //Display the window. frame.pack(); frame.setVisible(true); }   public static void main(String[] args) { //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } }