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JTable not visible inside JScrollPane

I have a JTable inside a JScrollPane. I want to show the table only when a particular button is pressed otherwise it should not be shown.
Inorder to incorporate that I have set the setVisible method of the ScrollPane to false while declaring and I set it to true inside the actionPerformed method of the JButton.
But the JTable is not visible even when I press the JButton.
Here's my code:
public class TableSample{
private JTable table;
....
private void initialize() {
JScrollPane scrollPane = new JScrollPane();
table = new JTable(new DefaultTableModel(new Object[][] {{null, null}, {null, null}, }, new String[] {"column1", "column2"}));
scrollPane.setViewportView(table);
scrollPane.setVisible(false);
JButton button = new JButton("Show Table");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
....
scrollPane.setVisible(true);
....
}
});
....
}
I have used group layout so the ScrollPane is added to frame with group layout.
Also the JTable is visible when I do not change the setVisible at all (by default true)
Any help is appreciated...

When you add components to a visible GUI the basic logic is:
panel.add(...);
panel.revalidate(); // to invoke the layout manager
panel.repaint(); // sometimes needed to make sure panel is repainted

JScrollPane (for JTable) fill and grow in MigLayout

It is difficult to describe what happens so here is a SSCCE:
public class TableInScrollPaneTest {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new TableInScrollPaneTest();
}
});
}
public TableInScrollPaneTest() {
JFrame frame = new JFrame();
frame.setSize(300, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
LayoutManager layout;
layout = new MigLayout("wrap 1, fill", "fill, grow", "[fill, grow 1][fill, grow 2]");
//layout = new GridLayout(2,1);
JPanel panel = new JPanel(layout);
JPanel placeHolder = new JPanel();
JPanel placeHolder2 = new JPanel();
placeHolder.setBackground(Color.GRAY);
placeHolder2.setBackground(Color.LIGHT_GRAY);
JTable table = this.createTable();
JScrollPane tableScrollPane = new JScrollPane(table,
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
//table.setPreferredScrollableViewportSize(new Dimension(5000,200));
panel.add(placeHolder, "");
panel.add(tableScrollPane, "");
//panel.add(placeHolder2, "");
frame.setContentPane(panel);
frame.setVisible(true);
}
private JTable createTable() {
String[] columnNames = "Name 1,Name 2,Name 3,Name 4,Name 5".split(",");
int rows = 30;
int cols = columnNames.length;
String[][] data = new String[rows][cols];
for(int i=0; i<rows; i++) {
for(int j=0; j<cols; j++) {
data[i][j] = "R"+i+" C"+j;
}
}
JTable table = new JTable(data, columnNames);
return table;
}
}
I want the scrollPane to use all available space when the frame gets resized by the user. But additionally I want another panel (placeHolder) to grow, too. For example the heigth of the frame divided by 3, the placeHolder gets 1 part and the scrollPane gets 2 parts. The GridLayout is kinda doing what I need, but I'm looking for a solution with MigLayout.
If you uncomment panel.add(placeHolder2, ""); and comment the line above it works.
EDIT1:
I tried using the sizegroup contraint. Now the placeHolder and the scrollPane have the same size, but I want the scrollPane take twice as much space. (Additionally in my programm I dont have a placeholder like this, but rather there are some labels, checkboxes and textfields. So sizegroup probably is not what I need except there are more ways to use it)

I found the solution here:
MigLayout confused by JTable objects contained in JScrollBar objects
and here:
How to set JScrollPane to show only a sepecific amount of rows
table.setPreferredScrollableViewportSize(null);
or
table.setPreferredScrollableViewportSize(table.getPreferredSize());
I don't know what's the difference between this code snippets, but they both do what I need.

Can't update JPanel

I have a JTable which contains a list of item and a JPanel with some components. When I click to my button, I want all information of the selected item in the JTable will be loaded to the JPanel. At the first time, it work well but at the further times when I click to my button the Jpanel appears with empty component.
The code when clicking to my button:
jbtUpdateContract.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
Object contractID = getValueOfSelectedRow(contractTable, 0);
Contract contract = contractTransaction.getContractByID(Integer.parseInt(contractID.toString()));
//Create Jpanel to display information
jplUpdateContractForm.removeAll();
jplUpdateContractForm = createContractForm(contract);
jplUpdateContractForm.revalidate();
//Modify contract frame
jfrmUpdateContract.getContentPane().add(jplUpdateContractForm,
BorderLayout.CENTER);
jfrmUpdateContract.setSize(400, 300);
jfrmUpdateContract.setVisible(true);
jfrmUpdateContract.setResizable(false);
}
});
And my createContractForm function:
public static JPanel createContractForm(Contract contract)
{
JPanel jplContractForm = new JPanel(new SpringLayout());
JLabel jlblAppointmentDate = new JLabel("Appointment date:", JLabel.TRAILING);
jlblAppointmentDate.setName("jlblAppointmentDate");
jplContractForm.add(jlblAppointmentDate);
final JTextField jtxtAppointmentDate = new JTextField(15);
jtxtAppointmentDate.setName("jtxtAppointmentDate");
jtxtAppointmentDate.setText(contract.getAppointmentDate());
jtxtAppointmentDate.setEditable(false);
jtxtAppointmentDate.addMouseListener(appointmentDateMouseListener(jtxtAppointmentDate));
jlblAppointmentDate.setLabelFor(jtxtAppointmentDate);
jplContractForm.add(jtxtAppointmentDate);
jplContractForm.setOpaque(true);
//***Customer Cobobox
JLabel jlblCustomer= new JLabel("Customer:", JLabel.TRAILING);
jlblCustomer.setName("jlblCustomer");
jplContractForm.add(jlblCustomer);
final JComboBox jcbxCustomer = new JComboBox();
jcbxCustomer.setName("jcbxCustomer");
//Load customers from DB to combobox
Customer[] customers = customerTransaction.getAllCustomer();
for(int i = 0; i < customers.length; i++)
jcbxCustomer.addItem(customers[i]);
System.out.println("----------CUSTOMER----------" + getIndexOfCustomerComboBoxItem(jcbxCustomer, contract.getCustomerSeq()));
jcbxCustomer.setSelectedIndex(getIndexOfCustomerComboBoxItem(jcbxCustomer, contract.getCustomerSeq()));
jlblCustomer.setLabelFor(jcbxCustomer);
jplContractForm.add(jcbxCustomer);
jplContractForm.setOpaque(true);
}
Please help me to explaint why the JPanel is empty as I describes above.
Regards.

The frame is already visible, so I don't think any of these lines of code will help.
jfrmUpdateContract.setSize(400, 300);
jfrmUpdateContract.setVisible(true);
jfrmUpdateContract.setResizable(false);
The revalidate() does nothing because you haven't added the panel to the frame yet. Try the revalidate() AFTER the panel has been added to the frame.
jplUpdateContractForm = createContractForm(contract);
//jplUpdateContractForm.revalidate();
jfrmUpdateContract.getContentPane().add(jplUpdateContractForm, BorderLayout.CENTER);
jplUpdateContractForm.revalidate();
If you need more help then post a proper SSCCE.

JTable design to synchronize with back-end data-structure

I have a JTable which is loaded from a data-structure using table model.The data-structure is of the format NavigableMap<Float,NavigableMap<Float,Boolean>>.An example data is:
Table Format:
Range f1,v1 f2,v2 f3,v3 f4,v4
12.1-30.2 30,true 32,false 45,true 50,false
30.2-45.6 30,true 32.4,true 45,true 50.1,true
The above data format is represented in the DS as
DS Format:
Key Value
12.1 <<30,true>,<32,false>,<45,true>,<50,false>>
30.2 <<30,true>,<32.4,true>,<45,true>,<50.1,true>>
45.6 null
I have managed to represent the above given data in Jtable using table-model.Once the data is loaded from the DS to the table I have to allow user edit.Now this is where I have problem.My doubt is whether is should keep the data structure synchronized with the changes in the table or should i recreate the DS from the table once the user finish editing and then replace it with the old one.
More over I need to validate the data(for example from above - Suppose the user want's to edit the value 30.1.He should only be allowed to enter values between 12.1 and 45.6.Since data the tables are string's (once loaded) I'm planning to use regex and key-listener and consume all user key presses which doesn't match the regex and values which doesn't come within the range.I'm not sure is this is a good idea or what are implications.I would like to get some suggestions on this.

I would recreate your DS once the user is finised editing the table.
You can always create a custom editor to display a popup dialog where you have two separate text fields for each value of the range. Then you can edit each field as a double value within your specified range and recreate the formatted string before saving it to the model. Here's an old example I have lying around to get you started:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
/*
* The editor button that brings up the dialog.
*/
//public class TablePopupEditor extends AbstractCellEditor
public class TablePopupEditor extends DefaultCellEditor
implements TableCellEditor
{
private PopupDialog popup;
private String currentText = "";
private JButton editorComponent;
public TablePopupEditor()
{
super(new JTextField());
setClickCountToStart(2);
// Use a JButton as the editor component
editorComponent = new JButton();
editorComponent.setBackground(Color.white);
editorComponent.setBorderPainted(false);
editorComponent.setContentAreaFilled( false );
// Set up the dialog where we do the actual editing
popup = new PopupDialog();
}
public Object getCellEditorValue()
{
return currentText;
}
public Component getTableCellEditorComponent(
JTable table, Object value, boolean isSelected, int row, int column)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
System.out.println("run");
popup.setText( currentText );
// popup.setLocationRelativeTo( editorComponent );
Point p = editorComponent.getLocationOnScreen();
popup.setLocation(p.x, p.y + editorComponent.getSize().height);
popup.show();
fireEditingStopped();
}
});
currentText = value.toString();
editorComponent.setText( currentText );
return editorComponent;
}
/*
* Simple dialog containing the actual editing component
*/
class PopupDialog extends JDialog implements ActionListener
{
private JTextArea textArea;
public PopupDialog()
{
super((Frame)null, "Change Description", true);
textArea = new JTextArea(5, 20);
textArea.setLineWrap( true );
textArea.setWrapStyleWord( true );
KeyStroke keyStroke = KeyStroke.getKeyStroke("ENTER");
textArea.getInputMap().put(keyStroke, "none");
JScrollPane scrollPane = new JScrollPane( textArea );
getContentPane().add( scrollPane );
JButton cancel = new JButton("Cancel");
cancel.addActionListener( this );
JButton ok = new JButton("Ok");
ok.setPreferredSize( cancel.getPreferredSize() );
ok.addActionListener( this );
JPanel buttons = new JPanel();
buttons.add( ok );
buttons.add( cancel );
getContentPane().add(buttons, BorderLayout.SOUTH);
pack();
getRootPane().setDefaultButton( ok );
}
public void setText(String text)
{
textArea.setText( text );
}
/*
* Save the changed text before hiding the popup
*/
public void actionPerformed(ActionEvent e)
{
if ("Ok".equals( e.getActionCommand() ) )
{
currentText = textArea.getText();
}
textArea.requestFocusInWindow();
setVisible( false );
}
}
public static void main(String[] args)
{
String[] columnNames = {"Item", "Description"};
Object[][] data =
{
{"Item 1", "Description of Item 1"},
{"Item 2", "Description of Item 2"},
{"Item 3", "Description of Item 3"}
};
JTable table = new JTable(data, columnNames);
table.getColumnModel().getColumn(1).setPreferredWidth(300);
table.setPreferredScrollableViewportSize(table.getPreferredSize());
JScrollPane scrollPane = new JScrollPane(table);
// Use the popup editor on the second column
TablePopupEditor popupEditor = new TablePopupEditor();
table.getColumnModel().getColumn(1).setCellEditor( popupEditor );
JFrame frame = new JFrame("Popup Editor Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add( scrollPane );
frame.pack();
frame.setLocationRelativeTo( null );
frame.setVisible(true);
}
}

How to make a scrollable JList to add details got from a JOptionPane

I want to repeatedly take input from the user(probably using a button) via a JOptionPane(already done) and store the details in something(how about a dynamic object array) and display this information as a list in a scrollable JList.
MY CODE
import java.awt.GridLayout;
import javax.swing.*;
class Flight {
public static void main(String[] args) {
//Panel
JPanel panel = new JPanel(new GridLayout(7, 2,20, 20));
//Add textfields here
JTextField txtflightno = new JTextField(8);
JTextField txtmechanicalstatus = new JTextField(8);
JTextField txtmedicalstatus = new JTextField(8);
JTextField txtfuellevel = new JTextField(8);
JTextField txtweathercondition = new JTextField(8);
JTextField txtfrequency = new JTextField(8);
JTextField txtflightpath = new JTextField(8);
//Add labels here
JLabel lblflightno = new JLabel("Flight No : ");
JLabel lblmechanicalstatus = new JLabel("Mechanical Status:");
JLabel lblmedicalstatus = new JLabel("Medical Status:");
JLabel lblfuellevel = new JLabel("Fuel Level:");
JLabel lblweathercondition = new JLabel("Weather Condition:");
JLabel lblfrequency = new JLabel("Frequency:");
JLabel lblflightpath = new JLabel("Flight Path:");
//Adding flightno to panel
panel.add(lblflightno);
panel.add(txtflightno);
//Adding mechanicalstatus to the panel
panel.add(lblmechanicalstatus);
panel.add(txtmechanicalstatus);
//Adding medicalstatus to the panel
panel.add(lblmedicalstatus);
panel.add(txtmedicalstatus);
//Adding fuellevel to the panel
panel.add(lblfuellevel);
panel.add(txtfuellevel);
//Adding weathercondition to the panel
panel.add(lblweathercondition);
panel.add(txtweathercondition);
//Adding frequency to the panel
panel.add(lblfrequency);
panel.add(txtfrequency);
//Adding flightpath to the panel
panel.add(lblflightpath);
panel.add(txtflightpath);
panel.setBounds(0, 0, 800, 600);
int result = JOptionPane.showConfirmDialog(null, panel, "Flight Details",
JOptionPane.OK_CANCEL_OPTION, JOptionPane.PLAIN_MESSAGE);
if (result == JOptionPane.OK_OPTION) {
}
}
}
How must I do the storing of the plane details ? How must I implement a scrollable JList ? Any suggestions.
Many Thanks

As discussed in How to Use Lists, JList uses a list model as the source of data it displays. Just add your data to a DefaultListModel, and use it to construct your list.
DefaultListModel dlm = new DefaultListModel();
// add data
JList list = new JList(dlm);
panel.add(new JScrollPane(list));

To make the JList scrollable, simply embed it in a JScrollPane. Instead of
add(myList, constraints);
do
add(new JScrollPane(myList), constraints);
To extend the list, just get the JList's ListModel (using getListModel) and use add to add objects.
More on using ListModels in Sun's tutorial.
More on ScrollPane in the Tutorial, too.

You've to use the ActionListener of Button, that you've missed in the code snippet.
In the OK Option :
JList jlist = ...;
jlist.add(txtflightno.getText());
jlist.add(txtmechanicalstatus.getText());
jlist.add(txtmedicalstatus.getText());
....
....
&
add(new JScrollPanel(myList), constraints);
After this use validate method of Component to update the list with this new item.
But one thing you should remember is that list displays each item row-wise.
I suggest you to use JTable with which you can display your items in a meaningful way...