Develop Reference

jtable not update after fireTableDataChanged, revalidate and repaint

It downloads data from ThingSpeak and show in jtable. I create a 'refresh' button which will download latest data and show in existing gui table.
get the latest data...work
store in List/arrays...work
update the jtable...Nop
I have tried fireTableDataChanged, setModel, revalidate, invalidate and repaint but still doesn't update the table. What am I missing?
public class Menu{
protected static List<String> list_name = new ArrayList<>();
// .....(10 more like above)
private JFrame frame = new JFrame("Temp");
private List<String[]> records_data = new ArrayList<String[]>();
private JTable table;
private DefaultTableModel model;
private String[][] data2 = new String[list_channel_ID.size()][11];
String[] columnNames_records = {"Location"}; // skip 10 more items
protected Menu(){
// Jframe > Jtabbedpane > jtable( I skip all these codes)
//- Table(Records)
for(int i = 0; i < list_channel_ID.size(); i++){
records_data.add(new String[]{ list_name.get(i) });} // Load data from List to jtable require format, skip 10 items
//table = new JTable(records_data.toArray(new Object[][] {}), columnNames_records); // when 'model' is not use
model = new DefaultTableModel(records_data.toArray(new Object[][] {}), columnNames_records);
//model = new DefaultTableModel(data2, columnNames);
table = new JTable(model);
JMenuItem process_refresh = new JMenuItem("Refresh");
process_refresh.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// Update the list
for(int i = 0; i < list_channel_ID.size(); i++){
records_data.add(new String[]{ list_name.get(i) }); // load from list again, skiped 10 item
}
model = new DefaultTableModel(records_data.toArray(new Object[][] {}), columnNames_records);
model.fireTableDataChanged();
//table.setModel(model);
table.revalidate();
//table.invalidate();
table.repaint();
}
});
}
}

Problem solve, I forgot to clear the list 'records_data' :|
I will leave it here if someone face the same problem and mind blown for 2 days like me
Working code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import java.lang.String;
import java.util.List;
import java.util.ArrayList;
public class Menu{
protected static List<String> list_name = List.of("AAA", "BBB", "CCC");
// .....(10 more like above)
private JFrame frame = new JFrame("Temp");
private List<String[]> records_data = new ArrayList<String[]>();
private List<String[]> result_data = new ArrayList<String[]>();
private JTable table, table2, table3;
private DefaultTableModel model;
private String[][] data2 = new String[3][11];
String[] columnNames_records = {"item A", "item B", "item C"}; // 10 more items
protected Menu(){
frame.setSize(1000, 600);
frame.setLayout(new GridLayout(2, 1));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//- Back Panel
JPanel panel = new JPanel(null);
frame.add(panel);
JPanel tab_panel = new JPanel(new GridLayout());
JTabbedPane tabbedPane = new JTabbedPane();
tabbedPane.setBounds(5, 100, 975, 500);
tabbedPane.add("Records", tab_panel);
frame.add(tabbedPane);
//- Table(Records)
for(int i = 0; i < 3; i++){
records_data.add(new String[]{ list_name.get(i) });
} // Load data from List to jtable require format, skiped 10 item
//table = new JTable(records_data.toArray(new Object[][] {}), columnNames_records);
model = new DefaultTableModel(records_data.toArray(new Object[][] {}), columnNames_records);
//model = new DefaultTableModel(data2, columnNames);
table = new JTable(model);
table.setRowHeight(20);
//- ScrollPane, allow scrolling if table too long
JScrollPane scrollPane = new JScrollPane(table);
tab_panel.add(scrollPane);
// Menu bar
JMenu menu_process = new JMenu("Process");
JMenuItem process_refresh = new JMenuItem("Refresh");
process_refresh.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
records_data.clear();
list_name = List.of("DDD", "EEE", "FFF"); // Update the list, hardcode for now
//list_name.add("KKK");
for(int i = 0; i < 3; i++){
records_data.add(new String[]{ list_name.get(i) }); // load from list again, skiped 10 item
}
model = new DefaultTableModel(records_data.toArray(new Object[][] {}), columnNames_records);
//model.fireTableDataChanged();
table.setModel(model);
//table.revalidate();
//table.invalidate();
//table.repaint();
}
});
menu_process.add(process_refresh);
JMenuBar menu_bar = new JMenuBar();
menu_bar.add(menu_process);
frame.setJMenuBar(menu_bar);
frame.setVisible(true);
}
public static void main(String[ ] args) {
new Menu();
}
}

populate DefaultTableModel after insert a row java

I am running a program with two frames. First one has a table, the second one has a form which allows adding a new user to the table. I think the problem is I didn't add a reference from the mainframe. I was trying different methods to refresh the mainframe programmatically, but it did not help so much. I read many articles on how to to it but I could find a solution. My table usually changes when I close my app and open it again. But I don't think is the right way to do it. I tried to delete elements from DefaultTableModel and populated jtable again, but did not get any results. Here is my code:
public Vector vector_jtable = new Vector();
public MainApp() {
initComponents();
Database b = new Database();
b.getAmountOfRows(getCount);
this.setLocationRelativeTo(null);
printResultDB();
}
//add function that is responsible for addding data to the table
public void postDataJtable() {
System.out.println("The vector is: " + vector_jtable);
Vector<String> header = new Vector<String>();
header.add("Number");
header.add("Name");
header.add("First Payment");
header.add("Next Payment");
header.add("Picture");
header.add("Phone");
header.add("Amount");
header.add("Age");
model = (DefaultTableModel)jTable2.getModel();
model.setDataVector(vector_jtable,header);
}
I created a vector that allows putting data from the second frame.
MainApp app;
public AddStudents(MainApp a) {
initComponents();
app = a;
this.setLocationRelativeTo(null);
jDateChooser1.setDateFormatString("yyyy-MM-dd");
jDateChooser2.setDateFormatString("yyyy-MM-dd");
}
After that, I push the button to send it out and update the mainframe, but nothing happened:
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
app.vector_jtable.add(name);
app.vector_jtable.add(first_p);
app.vector_jtable.add(next_p);
app.vector_jtable.add(picture);
app.vector_jtable.add(phone);
app.vector_jtable.add(amount);
app.vector_jtable.add(age);
app.postDataJtable();
My question. How to add a row in jtable and refresh it. I really stuck in this topic. I need your help.

Don't update the Vector.
When you want to change the data in the table you need to change the data in the TableModel.
You can use the addRow(...) method of the DefaultTableModel to add a new row of data.
So the basic logic is:
Vector<Object> row = new Vector<Object>();
row.add( someVariable1 );
row.add( someVariable2 );
...
modal.addRow( row ):
The model will then tell the table to repaint itself.
Edit:
There is no trick all you need is a reference to the model. Then you update the model.
Here is a simple example to prove the concept works:
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;
public class SSCCE extends JPanel
{
private DefaultTableModel model;
SSCCE()
{
setLayout( new BorderLayout() );
model = new DefaultTableModel(0, 2);
JTable table = new JTable( model );
add(new JScrollPane( table ));
JButton button = new JButton( "Add Row" );
add(button, BorderLayout.PAGE_END);
button.addActionListener( new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
Vector<Object> row = new Vector<Object>();
row.add( "" + model.getRowCount() );
row.add( new Date().toString() );
model.addRow( row );
}
});
}
private static void createAndShowGUI()
{
JFrame frame = new JFrame("SSCCE");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new SSCCE());
frame.pack();
frame.setLocationByPlatform( true );
frame.setVisible( true );
}
public static void main(String[] args) throws Exception
{
java.awt.EventQueue.invokeLater( () -> createAndShowGUI() );
/*
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
*/
}
}
If it doesn't work for you then you need to debug your code. Maybe you have two "model" variables? Maybe you have to "table" variables. Maybe your code isn't even executed. Did you add any debug statements to the code to make sure it is executed.
We can't solve your problem only point you in the right direction.

You can try some aspects from this example below. The example has two JFrame's - one with a JTable and the other the data entry fields. When the data is entered and the "UpdateTable" button is pressed (in the data entry class) the table is updated.
The example uses java.util.Observer and Observable to achieve this functionality.
The class with table:
import java.awt.*;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import java.util.Observer;
import java.util.Observable;
public class TableUpdateTester implements Observer {
private JTable table;
private static final Object[] TABLE_COLUMNS = {"Book", "Author"};
private static final Object [][] TABLE_DATA = {
{"Book 1", "author 1"}, {"Book 2", "author 1"}
};
public static void main(String [] args) {
TableUpdateTester tester = new TableUpdateTester();
new DataEntryClass(tester);
}
public TableUpdateTester() {
JFrame frame = new JFrame("Table Update Tester");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(getTablePanel());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private JPanel getTablePanel() {
table = new JTable(new DefaultTableModel(TABLE_DATA, TABLE_COLUMNS));
JScrollPane scrollpane = new JScrollPane(table);
scrollpane.setPreferredSize(new Dimension(400, 150));
scrollpane.setViewportView(table);
JPanel panel = new JPanel();
panel.add(scrollpane);
return panel;
}
// This is Observer's override method.
#Override public void update(Observable o, Object arg) {
String [] data = (String []) arg;
System.out.println("Data recieving: " + java.util.Arrays.toString(data));
DefaultTableModel model = (DefaultTableModel) table.getModel();
model.addRow(data);
}
}
The data entry class:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Observable;
public class DataEntryClass {
public DataEntryClass(TableUpdateTester observer) {
final DataObservable observable = new DataObservable();
observable.addObserver(observer);
JLabel label = new JLabel("Book: ");
final JTextField text = new JTextField(15);
JLabel label2 = new JLabel("Author: ");
final JTextField text2 = new JTextField(15);
JButton button = new JButton("Update Table");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String data1 = text.getText().isEmpty() ? "empty" : text.getText();
String data2 = text2.getText().isEmpty() ? "empty" : text2.getText();
String [] data = {data1, data2};
System.out.println("Data sent: " + java.util.Arrays.toString(data));
observable.changeData(data);
}
});
JPanel panel = new JPanel();
GridLayout grid = new GridLayout(3, 2);
panel.setLayout(grid);
panel.add(label);
panel.add(text);
panel.add(label2);
panel.add(text2);
panel.add(new JLabel(""));
panel.add(button);
JFrame frame = new JFrame();
frame.setTitle("Data Entry");
frame.add(panel);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.pack();
}
}
class DataObservable extends Observable {
DataObservable() {
super();
}
void changeData(Object data) {
// the two methods of Observable class
setChanged();
notifyObservers(data);
}
}

Finally, I found a solution to my problem. I will post my code here.
The Mainframe. I know the app with two frames is not a good option, because it's hard to fix the problem and it usually takes a lot of time to debug it.
/**
* Create the application.
*/
public MainApp() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 689, 345);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
//add table in DefaultTableModel
model = new DefaultTableModel(0,2);
table = new JTable(model);
table.setBounds(58, 38, 524, 197);
frame.getContentPane().add(table);
JScrollPane scrollPane = new JScrollPane();
scrollPane.setBounds(0, 0, 4, 4);
frame.getContentPane().add(scrollPane);
JButton btnNewButton = new JButton("Add");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
//Call a second frame
//add reference for DefaultTableModel and send it to another frame
AddData frame = new AddData(model);
frame.setVisible(true);
}
});
btnNewButton.setBounds(239, 269, 117, 29);
frame.getContentPane().add(btnNewButton);
}
The second frame, that is responsible for adding a new row in a table.
/**
* Create the frame.
*/
public AddData(DefaultTableModel model) {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JDateChooser dateChooser = new JDateChooser();
dateChooser.setBounds(115, 71, 188, 41);
contentPane.add(dateChooser);
JButton btnNewButton = new JButton("Send");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
//MainApp app = new MainApp();
Vector<Object> row = new Vector<Object>();
row.add(""+model.getRowCount());
row.add(dateChooser.getDate().toString());
model.addRow(row);
}
});
btnNewButton.setFont(new Font("Lucida Grande", Font.PLAIN, 20));
btnNewButton.setBounds(165, 192, 117, 41);
contentPane.add(btnNewButton);
}
I found my mistake. I did not send a link of DefaultTableModel into the second frame. That's why it was null every time. It was a really painful experience, but I learned from my mistakes. Thanks, everyone for your help. I really appriciate.

Unable to get column name in JTable in Swing

JTable table = new JTable(data,columnNames);
JScrollPane pane = new JScrollPane(table);
this.add(pane);
this.add(table);
My data is showing but column name is not showing on top.

A component can only have a single parent.
JScrollPane pane = new JScrollPane(table);
this.add(pane);
this.add(table);
First you add the table to the viewport of the scrollpane, which is good as this will cause the table header to automatically be displayed when the GUI is made visible.
But then you add the table directly to the frame, which is bad because it can no longer be displayed in the scrollpane.
Get rid of:
//this.add(table);
and then the scrollpane containing the table will be displayed properly on the frame.

Have a look at this example
import java.awt.Color;
import javax.swing.*;
public class table extends JFrame{
public table() {
setSize(600, 300);
String[] columnNames = {"A", "B", "C"};
Object[][] data = {
{"Moni", "adsad", 2},
{"Jhon", "ewrewr", 4},
{"Max", "zxczxc", 6}
};
JTable table = new JTable(data, columnNames);
JScrollPane tableSP = new JScrollPane(table);
JPanel tablePanel = new JPanel();
tablePanel.add(tableSP);
tablePanel.setBackground(Color.red);
add(tablePanel);
setTitle("Marks");
setLocationRelativeTo(null);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
table ex = new table();
ex.setVisible(true);
}
});
}
}

JTable, JComboBox - problems in showing JComboBox in second column

I have written this simple program:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
public class JcomboboxJtableDemo extends JPanel
implements ActionListener {
private DefaultTableModel tableModel;
JTable table = new JTable (tableModel);
private JScrollPane scrollpaneTable = new JScrollPane( table );
private JPanel PaneBottoniTabella = new JPanel( );
public JcomboboxJtableDemo() {
super(new BorderLayout());
String[] petStrings = { "Bird", "Cat", "Dog", "Rabbit", "Pig" };
JComboBox comboBox = new JComboBox(petStrings);
comboBox.setSelectedIndex(4);
tableModel = CreateTableModel();
tableModel.insertRow( 0, new Object[] {"Header col1", ""} );
tableModel.insertRow( 0, new Object[] {petStrings[0], ""} );
tableModel.insertRow( 0, new Object[] {petStrings[1], ""} );
tableModel.insertRow( 0, new Object[] {petStrings[2], ""} );
tableModel.insertRow( 0, new Object[] {petStrings[3], ""} );
tableModel.setValueAt("Header col2", 0, 1);
DefaultCellEditor editor = new DefaultCellEditor(comboBox);
table.getColumnModel().getColumn(0).setCellEditor(editor);
table.getColumnModel().getColumn(1).setCellEditor(editor);
//Lay out the demo.
add(comboBox, BorderLayout.PAGE_START);
add(table, BorderLayout.PAGE_END);
setBorder(BorderFactory.createEmptyBorder(20,20,20,20));
}
private final DefaultTableModel CreateTableModel () {
DefaultTableModel modello = new DefaultTableModel( new Object[] { "Col1","Col2" }, 0 ) {
#Override
public boolean isCellEditable(int row, int column) {
return true;
}
};
table.setModel(modello);
return modello;
}
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("ComboBoxDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
JComponent newContentPane = new JcomboboxJtableDemo();
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();
}
});
}
}
I you try to run it you will see that there is a problem in showing correctly the JComboBox components in the second column, in the first column the are correctly shown and you can see each selected item as set in the code, instead in the second column there are some problems: none on the relative cell.
Could you tell me why? How can I solve the problem?
Thanks

You're using the same JComboBox component for both ColumnModel columns which in turn share the same ComboBoxModel. Any change in the selected item from one column will be reflected in the other column. Create a second combobox
JComboBox comboBox2 = new JComboBox(petStrings);
...
table.getColumnModel().getColumn(1).setCellEditor(editor2);
so that any changes can occur independently in either column.

Dynamic Creation of JTable (Boolean Truth Tables)

I have a code that generates a truth table for a given Boolean Expression. For example, consider a user-input expression of (A+B)+(C+D). I have a string array headers[] that will store all necessary headers for the truth table.
In this case, it would contain: "A", "B", "C", "D", "A+B", "C+D", "(A+B)+(C+D)"
Then the generated truth table (a 2d int array TruthTable[][]) will contain the following data:
0000000
1000101
0100101
1100101
0010011
1010111
0110111
1110111
0001011
1001111
0101111
1101111
0011011
1011111
0111111
1111111
So the first element of the headers[] array will correspond to the first column of TruthTable[][]. How do I dynamically generate a truth table (using JTable) considering these data?

Create JTable with DefaultTableModel and insert new rows to table model.
Tutorial for it JTable and Model
Simple example for table:
public class Example extends JFrame{
private JTable table;
private DefaultTableModel modelTable;
public Example(){
init();
}
private void init() {
table = new JTable();
table.setGridColor(Color.BLACK);
table.setAutoResizeMode(2);
modelTable = new DefaultTableModel(new Object[][]{}, new String[] {"A", "B", "C"});
table.setModel(modelTable);
Object[][] data = new Object[][]{{"1","2","3"},{"4","5","6"}};
for(int i =0;i<data.length;i++){
modelTable.addRow(data[i]);
}
}
public static void main(String... s){
Example p = new Example();
p.add(new JScrollPane(p.table));
p.pack();
p.setVisible(true);
}
}

#alex2410 has a point when he says to use DefaultTableModel.
If you have some problem with FormLayout, download the JGoodies Form or simple change the layout =)
Maybe that's what You're looking for:
ThruthTablePanel
public class ThruthTablePanel extends JPanel {
private JScrollPane scrollPane;
private JTable table;
/**
* Create the panel.
*/
public ThruthTablePanel() {
initComponents();
}
private void initComponents() {
String columnsLayout = "3dlu, default:grow, 3dlu";
String rowsLayout = "3dlu, default:grow, 3dlu";
setLayout(new FormLayout(columnsLayout, rowsLayout));
scrollPane = new JScrollPane();
add(scrollPane, "2, 2, fill, fill");
Object[] headers = new Object[] { "A", "B", "C",
"D", "A+B", "C+D",
"(A+B)+(C+D)" };
String[] results = new String[] { "0000000", "1000101", "0100101",
"1100101", "0010011", "1010111", "0110111", "1110111",
"0001011", "1001111", "0101111", "1101111", "0011011",
"1011111", "0111111", "1111111" };
DefaultTableModel model = new DefaultTableModel(new Object[][] {}, headers);
model.setRowCount(results.length);
table = new JTable(model);
for (int j = 0; j < results.length; j++) {
for (int i = 0; i < results[j].length(); i++) {
model.setValueAt(results[j].charAt(i), j, i);
}
}
table.setFillsViewportHeight(true);
scrollPane.setViewportView(table);
}
public static void main(String[] args) {
JFrame frm = new JFrame();
frm.setContentPane(new ThruthTablePanel());
frm.setSize(new Dimension(400, 400));
// frm.pack();
frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frm.setLocationRelativeTo(null);
frm.setVisible(true);
}
But, if you have your ThruthTable[][] filled, you can just pass it as a parameter to the model.
Other Solution
DefaultTableModel model = new DefaultTableModel(/* Here you put your ThruthTable Vector */, headers);
table = new JTable(model);