Develop Reference

Cant add JTable to a GUI

I have a problem creating a JTable in my GUI. The GUI is created in the main thread and enables a file to be opened. The file is then used to create a table model and add info to it. A JTable is then created with the table model and added to the GUI. My problem is that the GUI doesn't show. Code:
package example;
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
public class Example extends JFrame{
private JButton button;
private JTable table;
private DefaultTableModel model;
private String path = "C:/Users/gilbert/Documents/11111.xls";
public Example(){
super("Example");
setLayout(new BorderLayout());
button = new JButton("Start");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
createTableModel_Three_By_Six(path);
}
});
add(button,BorderLayout.NORTH);
setSize(400, 400);
}
public void createTableModel_Three_By_Six(String fpath){
model = new DefaultTableModel();
ExcelParser exPareser = new ExcelParser(fpath);
int rows = exPareser.getRowNumber();
String rowToAdd[] = new String[3];
int i, j = 0;
while(j < rows){
i= 0;
while(i < 3){
rowToAdd[i] = exPareser.accessRow(j);
i++;
j++;
if(j == rows){
if(i==1){
rowToAdd[1] = "";
rowToAdd[2] = "";
}
else if(i==2){
rowToAdd[2] = "";
}
}
}
model.addRow(rowToAdd);
}
table = new JTable(model);
add(new JScrollPane(table));
}
public static void main(String[] args) {
Example app = new Example();
app.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
app.setVisible(true);
}
}

The problem, with your example, is the fact that there are no columns for the table, which means when you add the table to the frame, it doesn't know how to display the table contents.
So, by doing something as simple as...
model = new DefaultTableModel(new Object[]{"A", "B", "C"}, 0);
//...
table = new JTable(model);
add(new JScrollPane(table));
revalidate();
I was able to get the table to appear properly, with it's contents
Beware though, each time you call this method, a new JTable will be created. Instead, you should construct the JScrollPane and JTable at an earlier stage and simply update the TableModel

how to insert more than one jComponents into a cell in a jTable

I have a jTable which is populating according to my requirement . I want to add two comboboxes into all the cells in one column. So can anyone help me on this... ![here is my table ][1]
[1]: http://i.stack.imgur.com/nC9RL.jpg I need to add two comboboxes into all the rows of 1 st column. I did my coding into CREATE TABLE button which u can see in the image. here is my code so far : | |
int row=0;
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt)
{
row=Integer.parseInt(jTextField2.getText());
row=row-1;
DefaultTableModel dtm =(DefaultTableModel) jTable1.getModel();
TableColumn sportColumn = jTable1.getColumnModel().getColumn(1);
JComboBox subject= new JComboBox();
box.addItem("DDD");
box.addItem("CCC");
JComboBox teacher= new JComboBox();
box1.addItem("AAA");
box1.addItem("FFF");
JPanel jPanel = new JPanel();
GroupLayout gl= new GroupLayout(jPanel);
jPanel.setLayout(gl);
jPanel.add(box);
jPanel.add(box1);
dtm.setRowCount(0);
dtm.setRowCount(Integer.parseInt(jTextField1.getText()));
for (int i = 0; i < dtm.getRowCount(); i++) {
row++;
dtm.setValueAt(String.valueOf(row), i, 0);
sportColumn.setCellRenderer(
(TableCellRenderer) new DefaultTableCellRenderer()
.getTableCellRendererComponent(
jTable1, jPanel, true, true, i, 1));
}
}
jButton1===> create table Button / jTextField2===> number starts with / jTextField1===>number of rows

Caverts:
I think this is a crazy idea, personally. If your cell represents a compound object, then I'd be thinking about using a dialog or some other means, but that's me.
Personally, I think this is going to blow up in your face...
Example
The concepts presented are all based on the information from How to use Tables
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.HashMap;
import java.util.Map;
import javax.swing.AbstractCellEditor;
import javax.swing.ComboBoxModel;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellEditor;
import javax.swing.table.TableColumnModel;
public class Enrolement {
public static void main(String[] args) {
new Enrolement();
}
public Enrolement() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
DefaultTableModel model = new DefaultTableModel(new Object[]{"Subject"}, 10);
JTable tbl = new JTable(model);
TableColumnModel columnModel = tbl.getColumnModel();
columnModel.getColumn(0).setCellEditor(new SubjectTableCellEditor());
tbl.setRowHeight(columnModel.getColumn(0).getCellEditor().getTableCellEditorComponent(tbl, "Astronomy/Aurora Sinistra", true, 0, 0).getPreferredSize().height);
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new JScrollPane(tbl));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class SubjectTableCellEditor extends AbstractCellEditor implements TableCellEditor {
private JComboBox subject;
private JComboBox teacher;
private JPanel editor;
private Map<String, String[]> subjectTeachers = new HashMap<>(25);
public SubjectTableCellEditor() {
subjectTeachers.put("Astronomy", new String[]{"Aurora Sinistra"});
subjectTeachers.put("Charms", new String[]{"Filius Flitwick"});
subjectTeachers.put("Dark Arts", new String[]{"Igor Karkaroff", "Amycus Carrow"});
subjectTeachers.put("Defence Against the Dark Arts", new String[]{"Defence Against the Dark Arts",
"Quirinus Quirrell",
"Gilderoy Lockhart",
"Remus Lupin",
"Bartemius Crouch Jr.",
"Dolores Umbridge",
"Severus Snape",
"Amycus Carrow"});
subjectTeachers.put("Flying", new String[]{"Rolanda Hooch"});
subjectTeachers.put("Herbology", new String[]{"Herbert Beery",
"Pomona Sprout",
"Neville Longbottom"});
subjectTeachers.put("History of Magic", new String[]{"Professor Cuthbert Binns"});
subjectTeachers.put("Potions", new String[]{"Severus Snape",
"Horace Slughorn"});
subjectTeachers.put("Transfiguration", new String[]{"Minerva McGonagall",
"Albus Dumbledore"});
subject = new JComboBox(new String[]{
"Astronomy",
"Charms",
"Dark Arts",
"Defence Against the Dark Arts",
"Flying",
"Herbology",
"History of Magic",
"Potions",
"Transfiguration"
});
teacher = new JComboBox();
editor = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.weightx = 1;
gbc.fill = GridBagConstraints.HORIZONTAL;
editor.add(subject, gbc);
editor.add(teacher, gbc);
subject.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
teacher.setModel(new DefaultComboBoxModel(subjectTeachers.get(subject.getSelectedItem())));
}
});
}
#Override
public Object getCellEditorValue() {
return subject.getSelectedItem() + "/" + teacher.getSelectedItem();
}
#Override
public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column) {
if (value instanceof String) {
String parts[] = value.toString().split("/");
subject.setSelectedItem(parts[0]);
teacher.setSelectedItem(parts[1]);
}
editor.setBackground(isSelected ? table.getSelectionBackground() : table.getBackground());
return editor;
}
}
}

JTable autoscroll methods are one row too high

Here is an example table of what I have been using:
JScrollPane scrollPane = new JScrollPane();
contentPane.add(scrollPane);
table = new JTable();
DefaultTableModel tableModel = new DefaultTableModel(new Object[]{"Row 1","Row 2"},0);
table.setModel(tableModel);
scrollPane.setViewportView(table);
I've attempted to use the following autoscrolling methods both with the same result.
// Method 1
JScrollBar vertical = scrollPane.getVerticalScrollBar();
vertical.setValue(vertical.getMaximum());
// Method 2
table.scrollRectToVisible(table.getCellRect(table.getRowCount(), 0, true));
Both examples go to the near-bottom of the table, up until the last (bottom) row that the user has to scroll down to see, only to happen again when another row is added.
EDIT: Example code to replicate the problem
import java.awt.*;
import javax.swing.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JScrollPane;
import javax.swing.table.DefaultTableModel;
public class ScrollTableEx extends JFrame {
private static final long serialVersionUID = 1L;
public int i = 100;
public JScrollPane scrollPane;
public JPanel contentPane;
public JTable table;
public JButton add;
public DefaultTableModel model = new DefaultTableModel(new Object[] { "Int (+)", "Int (-)" }, 0);
public static void main(String[] args) {
ScrollTableEx frame = new ScrollTableEx();
frame.setVisible(true);
}
public ScrollTableEx() {
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new BorderLayout());
setSize(500,400);
scrollPane = new JScrollPane();
table = new JTable();
table.setCellSelectionEnabled(true);
table.setModel(model);
scrollPane.setViewportView(table);
for (int i = 0; i < 100; i++) {
model.addRow(new Object[] { i, i * -1 });
Rectangle goodRect = table.getCellRect(model.getRowCount() - 1, 0, true);
table.scrollRectToVisible(goodRect);
}
JButton add = new JButton("Add");
add.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
Rectangle goodRect = table.getCellRect(model.getRowCount() - 1, 0, true);
table.scrollRectToVisible(goodRect);
model.addRow(new Object[] { i, i * -1 });
i++;
}
});
add(add, BorderLayout.NORTH);
add(scrollPane, BorderLayout.CENTER);
}
}

The problem is, JTable and TableModel are both 0 indexed. That is, the last value is actually rowCount - 1.
So when you use table.getCellRect(table.getRowCount(), 0, true), it's actually returning a Rectangle of the right position, just with a 0 height, because the row doesn't actually exist.
Instead you want to use table.getCellRect(table.getRowCount() - 1, 0, true)
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;
public class ScrollTable {
public static void main(String[] args) {
new ScrollTable();
}
public ScrollTable() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
final DefaultTableModel model = new DefaultTableModel(new Object[]{"Test"}, 0);
for (int index = 0; index < 100; index++) {
model.addRow(new Object[]{index});
}
final JTable table = new JTable(model);
JButton add = new JButton("Add");
add.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
model.addRow(new Object[]{model.getRowCount()});
Rectangle badRect = table.getCellRect(model.getRowCount(), 0, true);
Rectangle goodRect = table.getCellRect(model.getRowCount() - 1, 0, true);
System.out.println("bad = " + badRect);
System.out.println("goodRect = " + goodRect);
table.scrollRectToVisible(goodRect);
}
});
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new JScrollPane(table));
frame.add(add, BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}
I would avoid using .setBounds where possible. It does not take into consideration the variety of differences that exist between different computers and OS's and while it might look perfectly fine when you are developing, when you move it another system, it could produce undeseriable results - IMHO

JTable autoscroll to the bottom in Java

I would like the JTable to autoscroll to the bottom whenever I add a new column and show the last 10 rows. However, I have the option of scrolling to anywhere I want (mouse listener?). Do you know how to do that? Here's the code I have so far. It builds a JTable and adds a new row for every mouse click on the JButton.
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;
public class sampleGUI extends JFrame implements ActionListener {
private JButton incrementButton;
private JTable table;
private DefaultTableModel model;
private int count;
private JScrollPane scroll;
public sampleGUI() {
JFrame frame = new JFrame("sample frame");
frame.setLayout(new BorderLayout());
incrementButton = new JButton("Increase the count!");
model = new DefaultTableModel();
model.addColumn("column 1");
table = new JTable(model);
frame.add(incrementButton, BorderLayout.NORTH);
scroll = new JScrollPane(table)
frame.add(scroll, BorderLayout.CENTER);
count = 0;
incrementButton.addActionListener(this);
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
#Override
public synchronized void actionPerformed(ActionEvent e) {
if (e.getSource() == incrementButton) {
count++;
model.addRow(new Object[] { count });
}
}
public static void main(final String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
sampleGUI gui = new sampleGUI();
}
});
}
}
Thanks!

Required to change selection in JTable, add code line
table.changeSelection(table.getRowCount() - 1, 0, false, false);
to
public (synchronized) void actionPerformed(ActionEvent e) {

I would like the JTable to autoscroll to the bottom whenever I add a new column
I assume you mean scroll to the bottom when you add a new row?
model.addRow(new Object[] { count });
table.scrollRectToVisible(...);

You forget add JScrollPane to the table :
//...
frame.add(new JScrollPane(table), BorderLayout.CENTER);
//...
and don't forget
import javax.swing.JScrollPane;

could not set the column width to zero i.e. not made column invisible

I am trying to make one column from JTable, invisible by setting width to zero but it could not happen and it remain visible to width = 15. Here is code -
public void restoreColumnWithWidth(int column, int width) {
try {
TableColumn tableColumn = table.getColumnModel().getColumn(column);
table.getTableHeader().setResizingColumn(tableColumn);
tableColumn.setWidth(width);
tableColumn.setMaxWidth(width);
tableColumn.setMinWidth(width);
tableColumn.setPreferredWidth(width);
} catch (Exception ex) {
}
}
What is wrong with the code ?

not, never to remove TableColumn from TableModel, this is wrong suggestion, instead of to use built-in method JTable#removeColumn(TableColumn aColumn),
notice, this method remove column only from View, in the model is removed column still presents, and you can revert that, visible the removed column by using JTable#addColumn(TableColumn aColumn)
EDIT
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Stack;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.WindowConstants;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;
public class TableRowHeight {
private static final long serialVersionUID = 1L;
private JFrame frame = new JFrame("p*s*s*s*s*t*t");
private String[] columnNames = {"one", "two", "Playing with", "four", "five",};
private String[][] data = {
{"aaaaaa", "bbbbbb", "cccccc", "dddddd", "eeeeeee",},
{"bbbbbb", "cccccc", "dddddd", "eeeeeee", "aaaaaa",},
{"cccccc", "dddddd", "eeeeeee", "aaaaaa", "bbbbbb",},
{"dddddd", "eeeeeee", "aaaaaa", "bbbbbb", "cccccc",},
{"eeeeeee", "aaaaaa", "bbbbbb", "cccccc", "dddddd",}};
private JTable table = new JTable(new DefaultTableModel(data, columnNames));
private TableColumnModel tcm = table.getColumnModel();
private Stack<TableColumn> colDeleted = new Stack<TableColumn>();
private JButton restoreButton = new JButton("Restore Column Size");
private JButton hideButton = new JButton("Set Column Size to Zero");
private JButton deleteButton = new JButton("Delete Column");
private JButton addButton = new JButton("Restore Column");
public TableRowHeight() {
table.setRowMargin(4);
table.setRowHeight(30);
table.setFont(new Font("SansSerif", Font.BOLD + Font.PLAIN, 20));
JScrollPane scrollPane = new JScrollPane(table);
for (int i = 0; i < (tcm.getColumnCount()); i++) {
tcm.getColumn(i).setPreferredWidth(100);
}
table.setPreferredScrollableViewportSize(table.getPreferredSize());
restoreButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
tcm.getColumn(2).setPreferredWidth(100);
}
});
hideButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
tcm.getColumn(2).setPreferredWidth(000);
}
});
deleteButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (table.getColumnCount() > 0) {
TableColumn colToDelete = table.getColumnModel().getColumn(table.getColumnCount() - 1);
table.removeColumn(colToDelete);
table.validate();
colDeleted.push(colToDelete);
addButton.setEnabled(true);
} else {
deleteButton.setEnabled(false);
}
}
});
addButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (colDeleted.size() > 0) {
table.addColumn(colDeleted.pop());
table.validate();
deleteButton.setEnabled(true);
} else {
addButton.setEnabled(false);
}
}
});
JPanel btnPanel = new JPanel();
btnPanel.add(hideButton);
btnPanel.add(restoreButton);
btnPanel.add(deleteButton);
btnPanel.add(addButton);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.add(scrollPane, BorderLayout.CENTER);
frame.add(btnPanel, BorderLayout.SOUTH);
frame.pack();
frame.setLocation(150, 150);
frame.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
TableRowHeight frame = new TableRowHeight();
}
});
}
}
EDIT2
you have to check too
JTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
JTable.getTableHeader().setReorderingAllowed(false);

If it should be removed, and not just hidden: Remove it from the table-model.
If it only should be hidden and later shown, you can remove the TableColumn from the TableColumnModel
Making the column height 0 is a bit bogus.