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I can't refresh the contents of a JTable

imarquez
imarquez asked
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Last Modified: 2012-06-21
Hello:

I'm working on a little database aplication in Java, I have a JTable that gets the data from a MySQL database, the table loads the data OK, but when I try to refresh it if a row is inserted or updated the results are not updated
Here is the code I made:

The method refrescarGrilla is the method that fills the data when the table is displayed, the secon method is used to refresh the data
What am I doing wrong?
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Commented:
It will help if you actually post the code... :)
ksivananthVice President

Commented:
where is the code?
btw, you will need to call fireTableDataChanged() or fireTableRowsInserted(int, int) after updating the data in the model!

Author

Commented:
I attached a code snippet but didn't show

Here it is:


public void refrescarGrilla(){
        headVector.addElement("Nro Ped");
        headVector.addElement("Fecha Pedido");
        headVector.addElement("Cliente");
        headVector.addElement("Direccion");
        headVector.addElement("Articulo");
        headVector.addElement("Movil");
        headVector.addElement("Movil prox");
        headVector.addElement("Cantidad");
        headVector.addElement("Flete");
        headVector.addElement("Total");
        List lista;
        lista = Persistir.getInstancia().listarPedidos();
        DefaultTableModel modelo = new DefaultTableModel();
        modelo.setDataVector((Vector) lista, headVector);
        jTable1.setModel(modelo);
        modelo.addTableModelListener(jTable1);
        jTable1 = tblRes.autoResizeColWidth(jTable1, modelo);
        modelo.fireTableDataChanged();
    }

    public void actualizarGrilla(){

        List lista;
        lista = Persistir.getInstancia().listarPedidos();
        DefaultTableModel modelo = new DefaultTableModel();
        modelo.addTableModelListener(jTable1);
        modelo.setDataVector((Vector) lista, headVector);
        jTable1 = tblRes.autoResizeColWidth(jTable1, modelo);
        modelo.fireTableDataChanged();
       
    }
CERTIFIED EXPERT
Top Expert 2016

Commented:
refrescarGrilla should be called in the EventDispatchThread. Run the update in another thread.

Use the (execellently documented) SwingWorker to do this

Author

Commented:
could you provide an example? I never used it before
CERTIFIED EXPERT
Top Expert 2016

Commented:
There are examples in the docs

Author

Commented:
Do I need to create another class that extends SwingWorker or I should make the JTable extend it so I can call the method to refresh the table?
CERTIFIED EXPERT
Top Expert 2016

Commented:
Create a subclass of SwingWorker. Call it TableRefresher of something
ksivananthVice President

Commented:
try this and let me know,

public void refrescarGrilla(){
        headVector.addElement("Nro Ped");
        headVector.addElement("Fecha Pedido");
        headVector.addElement("Cliente");
        headVector.addElement("Direccion");
        headVector.addElement("Articulo");
        headVector.addElement("Movil");
        headVector.addElement("Movil prox");
        headVector.addElement("Cantidad");
        headVector.addElement("Flete");
        headVector.addElement("Total");
        List lista;
        lista = Persistir.getInstancia().listarPedidos();
        DefaultTableModel modelo = ( DefaultTableModel )jTable1.getModel();
        modelo.setDataVector((Vector) lista, headVector);
    }

SwingWorker is needed if you want to do the operations in separate threads!

Author

Commented:
ksivananth, it didn't work, the table still doesn't show the update, I'll try using SwingWorker, but i still have no clue of how to do it, how can I run these methos in the eventDispatcher Thread using SwingWorker?
ksivananthVice President

Commented:
>>it didn't work, the table still doesn't show the update

it should work, are you sure the reference of jTable1 is same?
ksivananthVice President

Commented:
this simple example works,

class TableGUI extends JFrame implements ActionListener
{
      JTable tb;
      JButton bt;
      
      public TableGUI()
      {
            setTitle("This is a table GUI");
            setSize(300,300);
            setLayout(new BorderLayout());
            
          Object[][] studentDetails = {{new String("Mary"), new String("A101"), new Double(22.1)},{new String("John"), new String("A102"), new Double(25.1)}};
          String[] title = {"Name", "ID", "Score"};
          DefaultTableModel model = new DefaultTableModel( studentDetails, title ) ;
          tb = new JTable( model );            
          bt = new JButton("Score");
          bt.addActionListener(this);
          add(new JScrollPane(tb), BorderLayout.CENTER);
          add(bt, BorderLayout.SOUTH);
      }
      
      public void actionPerformed(ActionEvent ae)
      {
            int[] row = tb.getSelectedRows();
            if(row.length == 0)
            {
                Object[][] studentDetails = {{new String("Mary - 1"), new String("A101"), new Double(22.1)},{new String("John - 1"), new String("A102"), new Double(25.1)}};
                String[] title = {"Name", "ID", "Score"};
                DefaultTableModel model = ( DefaultTableModel )tb.getModel() ;
                model.setDataVector( studentDetails, title ) ;
            }
      }

      public static void main(String[] args)
      {
            JFrame f = new TableGUI();
            f.setVisible(true);
      }
}
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Top Expert 2016

Commented:
Actually in this case you can just update the model and call fireTableDataChanged in the doInBackground method
ksivananthVice President

Commented:
do you see any exception?

Commented:
>>it didn't work, the table still doesn't show the update
posting the code that did not work might help someone spot something wrong :) Just a note.
ksivananthVice President

Commented:
if it doesn't work, it won't work with SwingWorker too!

Author

Commented:
this is the code that updates an object to the database and calls for the actualizarGrilla method, which does refresh the updated rows

private void btnActualizarPedidoActionPerformed(java.awt.event.ActionEvent evt) {
        Persistir p = Persistir.getInstancia();
        int row = jTable1.getSelectedRow();
        Integer val =(Integer) jTable1.getValueAt(row, 0);
        Pedidos ped = new Pedidos();
        Articulos art = new Articulos();
        art=(Articulos) cboArticulos.getSelectedItem();
        int id = val;
        ped = p.buscarPedidoPorId(id);
        ped.setMovilAsignado((Moviles) cboMoviles.getSelectedItem());
       
        ped.setCantidad(Integer.parseInt(txtCantidad.getText()));
        ped.setFlete(Integer.parseInt(txtFlete.getText()));
        ped.setIdArticulo(art);
        ped.setMovilAsignado((Moviles) cboMoviles.getSelectedItem());
        ped.setObservaciones(txtObservaciones.getText());


        p.actualizarPedido(ped);
        actualizarGrilla();
}

Author

Commented:
This is the full code for the class, it´s an  internal frame form generated with netbeans.
intFrmPedidos.zip
CERTIFIED EXPERT
Top Expert 2016

Commented:
>>private void btnActualizarPedidoActionPerformed(java.awt.event.ActionEvent evt) {

An intensive code that run in there must be moved into a background thread or it will block your GUI

Author

Commented:
Ok, how do I move it to a background thread? I never did "thread management" before
ksivananthVice President

Commented:
>>how do I move it to a background thread

I would suggest you to resolve the problem in hand first and then move to thread as that would take some time for you to understand!
ksivananthVice President

Commented:
>>this is the code that updates an object to the database and calls for the actualizarGrilla method, which does refresh the updated rows

I was under the impression that you are calling refrescarGrilla on button click!

Author

Commented:
but, the problem in hand wouldn't be the refreshing of the table? wich would be solved moving those methods to another thread? excuse me if i'm lost, but this problem is driving me nuts and i haven't found a working solution in any other place
ksivananthVice President

Commented:
try this then,

public void actualizarGrilla(){

        List lista;
        lista = Persistir.getInstancia().listarPedidos();
        DefaultTableModel modelo = ( DefaultTableModel )jTable1.getModel();
        modelo.setDataVector((Vector) lista, headVector);
    }

Author

Commented:
Yes, the button takes the selected object from the row, updates the object with new values and saves it back to de database, and refrescarGrilla is called at the end to reflect those changes
ksivananthVice President

Commented:
sorry I am lost with the method names! let me take the look at your complete code!

Author

Commented:
refrescarGrilla would be "refreshGrid" and actualizarGrilla "updateGrid", the names are very similar so the confusion is understandable
ksivananthVice President

Commented:
the refrescarGrilla is called no where in the actionperformed method!
ksivananthVice President

Commented:
all the places you are just calling actualizarGrilla!
ksivananthVice President

Commented:
did you try my comment #24040101?

Author

Commented:
ksivananth: I did try. The same thing, it's not refreshing the table. I don't have the slightest idea where the problem is. I'm starting to feel defeated because I did everithing I'm supposed to do (except the "thread thing") but nothing worked out
ksivananthVice President

Commented:
"thread thing" is just for efficience and won't fix the problem!
ksivananthVice President

Commented:
can you check if
lista = Persistir.getInstancia().listarPedidos();
returns updated list?

Author

Commented:
Sorry, my mistake. But I need to find where the problem is, I tried all the solutions people gave me but still nothing. You guys are my last hope

I'm starting to sound pathetic, sorry
ksivananthVice President

Commented:
it would be lot easier for you to locate the problematic area if you debug the code line by line!

Author

Commented:
I ran a debug line by line many times but there is not a single problem in the execution

Author

Commented:
didn't anyone found a solution?

Author

Commented:
Ok, I added a button that calls for the refreshing of the table.
Thing is if I update a record the table don't show the updates, if I hit the new button nothing happens.... After waiting a few seconds if I hit it again calling for actualizarGrilla() THE TABLE REFRESHES!!!!!! why is that?
ksivananthVice President

Commented:
>>After waiting a few seconds if I hit it again calling for actualizarGrilla() THE TABLE REFRESHES!!!!!! why is that?

could be that it takes some time to save the data to DB table. so if you press the button before the data get saved to DB, you won't see the update in JTable but if wait for the data to be updated in DB and then hit that button you see the update!

Author

Commented:
But the funny thing is that the List that gets the updated data is loaded normally and in time, so the delay has no sense, and I don't really know why is that.
ksivananthVice President

Commented:
>>List that gets the updated data is loaded normally and in time

how do you say this?
ksivananthVice President

Commented:
you can have some SOPs to know what happens when you click the button!

Author

Commented:
After running a debug in Netbeans I added a watch to the List object that gets the result from the DB, the List gets de data updated, the model takes the new list but the changes are not shown in the table

Author

Commented:
I tried to run the model and table updating processes in the background, it didn't throw any exception but the results are the same, no data updated in the table. Maybe I'm not doing it right.

public void actualizarGrilla(){
        SwingWorker<DefaultTableModel, Object> worker = new SwingWorker<DefaultTableModel, Object>(){

            @Override
            protected DefaultTableModel doInBackground(){
                Vector lista;
                lista = Persistir.getInstancia().listarPedidos();
                DefaultTableModel modelo = new DefaultTableModel();
                modelo.addTableModelListener(jTable1);
                modelo.setDataVector(lista, headVector);
                return modelo;
            }
            @Override
            protected void done(){
                try {
                    DefaultTableModel modelo = get();
                    jTable1 = tblRes.autoResizeColWidth(jTable1, modelo);
                    modelo.fireTableDataChanged();
                } catch (InterruptedException ex) {
                    Logger.getLogger(intFrmPedidos.class.getName()).log(Level.SEVERE, null, ex);
                } catch (ExecutionException ex) {
                    Logger.getLogger(intFrmPedidos.class.getName()).log(Level.SEVERE, null, ex);
                }
            }

        };
        worker.execute();
     }
ksivananthVice President

Commented:
if you use SwingWorker, in the doInBackground method you would do the DB update operation and in the done method you would get the updated list and set it to model!

>>Vector lista;
                lista = Persistir.getInstancia().listarPedidos();
                DefaultTableModel modelo = new DefaultTableModel();
                modelo.addTableModelListener(jTable1);
                modelo.setDataVector(lista, headVector);
>>

btw, the above code is not correct, refer my earlier comments where have taken the model from the table itself instead of creating it!
ksivananthVice President

Commented:
and as I sadi earlier, SwingWorker won't solve the issue you have but its an efficient way of doing it!

Author

Commented:
Ok, thanks for the advice, your patienece is admirable, I'm feeling like pain in the a.... sorry.  I already did take the model from the table in previous tryouts but the result is the same, that delay in the updating table process seems inexplicable
Commented:
This one is on us!
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