Develop Reference

How can I access an Array List's elements inside an ActionListener from another ActionListener?

I have two Action Listener inner-classes inside one main class. Each one corresponds to its own button. One of the Action Listeners is coded to generate an Array List. The other simply writes that Array List to a Text Field.
My question is how can I refer to/access that data from the other Action Listener? The code below compiles but when I check the contents of the Array List from the second Action Listener, it is empty ([]).
I'm guessing this has something to do with the Array List re-instantiating when the other Action Listener's actionPerformed method is called. How can I work around this? (The code here is just the 2 Action Listeners).
// Create a Button Listener Inner Class for Input Route Button.
class InputRouteButtonHandler implements ActionListener {
List<String> routeStopList = new ArrayList<String>();
public void actionPerformed(ActionEvent event) {
String city1 = (String) cityCombo1.getSelectedItem();
String city2 = (String) cityCombo2.getSelectedItem();
if (city1.equals(city2)) {
JOptionPane.showMessageDialog(null, "Invalid route chosen. Please choose two different cities.");
} else {
routeStopList.add(city1); //Add city1 to start of array.
int dialogResult;
do {
String routeStop = JOptionPane.showInputDialog("Enter a stop between the 2 cities:");
routeStopList.add(routeStop);
dialogResult = JOptionPane.showConfirmDialog(null, "Add another stop?");
} while (dialogResult.equals(JOptionPane.YES_OPTION));
routeStopList.add(city2); //Add city2 to end of array.
System.out.println(routeStopList); //Just checking ArrayList contents
}
}
}
// Create a Button Listener Inner Class for Route Button.
class RouteButtonHandler extends InputRouteButtonHandler implements ActionListener {
public void actionPerformed(ActionEvent event) {
String city1 = (String) cityCombo1.getSelectedItem();
String city2 = (String) cityCombo2.getSelectedItem();
System.out.println(routeStopList); //Just checking ArrayList contents
if (city1.equals(city2)) {
JOptionPane.showMessageDialog(null, "Invalid route chosen. Please choose two different cities.");
} else {
for (int i = 0; i < routeStopList.size(); i++) {
String addedRoute = routeStopList.get(i);
adminPanelTextArea.append(addedRoute + "\n");
}
}
}
}

You are right, your problem is due to your creating two ArrayLists, lists that have absolulely no relationship with each other, other than holding the same type of objects and having the same names. A solution is to create one Model class that is shared by both ActionListener classes, and in this model class, have your ArrayList. Then give your ArrayList classes a setModel(Model model) method or constructor, and pass in a reference to the single Model object into both ActionListeners.
One other consideration is to use a single Control class to handle your listener type code, and then have your Control class hold a Model field.
As an aside, this is dangerous code:
if (city1 == city2) {
Don't compare Strings using ==. Use the equals(...) or the equalsIgnoreCase(...) method instead. Understand that == checks if the two objects are the same which is not what you're interested in. The methods on the other hand check if the two Strings have the same characters in the same order, and that's what matters here.
For example, say you have two buttons that want to manipulate a JList, one wanting to add text, the other wanting to clear it, then you could pass the JList's model into both button handlers. An example program could look like:
import java.awt.BorderLayout;
import java.awt.event.*;
import javax.swing.*;
#SuppressWarnings("serial")
public class ShareList extends JPanel {
private static final String PROTOTYPE_CELL_VALUE = "ABCDEFGHIJKLMNOP";
private static final int VISIBLE_ROW_COUNT = 10;
private JTextField textField = new JTextField(10);
private DefaultListModel<String> listModel = new DefaultListModel<>();
private JList<String> myList = new JList<>(listModel);
public ShareList() {
myList.setPrototypeCellValue(PROTOTYPE_CELL_VALUE);
myList.setVisibleRowCount(VISIBLE_ROW_COUNT);
myList.setFocusable(false);
JPanel buttonPanel = new JPanel();
AddHandler addHandler = new AddHandler(listModel, this);
textField.addActionListener(addHandler);
buttonPanel.add(new JButton(addHandler));
buttonPanel.add(new JButton(new ClearHandler(listModel)));
JPanel rightPanel = new JPanel(new BorderLayout());
rightPanel.add(textField, BorderLayout.NORTH);
rightPanel.add(buttonPanel, BorderLayout.CENTER);
setLayout(new BoxLayout(this, BoxLayout.LINE_AXIS));
add(new JScrollPane(myList));
add(rightPanel);
}
public String getText() {
textField.selectAll();
return textField.getText();
}
private static void createAndShowGui() {
JFrame frame = new JFrame("ShareList");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new ShareList());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
#SuppressWarnings("serial")
class AddHandler extends AbstractAction {
private DefaultListModel<String> listModel;
private ShareList shareList;
public AddHandler(DefaultListModel<String> listModel, ShareList shareList) {
super("Add");
putValue(MNEMONIC_KEY, KeyEvent.VK_A);
this.listModel = listModel;
this.shareList = shareList;
}
public void actionPerformed(ActionEvent e) {
String text = shareList.getText();
listModel.addElement(text);
};
}
#SuppressWarnings("serial")
class ClearHandler extends AbstractAction {
private DefaultListModel<String> listModel;
public ClearHandler(DefaultListModel<String> listModel) {
super("Clear");
putValue(MNEMONIC_KEY, KeyEvent.VK_C);
this.listModel = listModel;
}
public void actionPerformed(ActionEvent e) {
listModel.clear();
};
}

Trouble with RadioButtons and booleans connection

Well its weird. I am not good with radiobuttons by the way. But I made a JPanel program in netbeans which includes a RadioButton. You enter all this information with JTextFields(no problem) and then lastly I had a JButton which you click the choice you want. Then I have a JButton that takes all the information and outputs this. For the RadioButton, I first entered the usual:
family = new JRadioButton("Family", true);
friend = new JRadioButton("Friend");
relative = new JRadioButton("Relative");
friendFriend = new JRadioButton("Friend of Friend");
ButtonGroup group = new ButtonGroup();
group.add (friend);
group.add (family);
group.add (relative);
group.add (friendFriend);
(I'm not sure if I needed a listner for the RadioButtons or not but my program still seems to "crash" no matter what).
then I had one action listner for the JButton which included all the textfields and radio buttons. But the RadioButton is the issue.
In the action listner I had:
Object source = event.getSource();
if (source == family)
relation1 = true;
else
if (source == friend)
relation2 = true;
else
if(source == relative)
relation3 = true;
else
if(source == friendFriend)
relation4 = true;
Then I made a relation class:
public class Relation {
private boolean arrayFamily, arrayFriend, arrayRelative, arrayFriendFriend;
public Relation(boolean relation1, boolean relation2, boolean relation3,
boolean relation4)
{
this.arrayFamily = relation1;
this.arrayFriend = relation2;
this.arrayRelative = relation3;
this.arrayFriendFriend = relation4;
}
public String relations ()
{
String relationship = null;
if(arrayFamily && !arrayFriend && !arrayRelative && !arrayFriendFriend == true)
{
relationship = "Family";
}
else
if(arrayFriend && !arrayFamily && !arrayRelative &&
!arrayFriendFriend == true)
{
relationship = "Friend";
}
else
if(arrayRelative && !arrayFamily && !arrayFriend &&
!arrayFriendFriend == true)
{
relationship = "Relative";
}
else
if(arrayFriendFriend && !arrayFamily && !arrayFriend &&
!arrayRelative == true)
{
relationship = "Friend of a Friend";
}
return relationship;
}
}
LASTLY back in the action listner, I implementer this class:
Relation relationship = new Relation(relation1, relation2, relation3
, relation4);
String arrayRelation = relationship.relations();
I lastly included arrayRelation in an array but the array worked fine.
My problem is that the output of the array for my RadioButtons keeps reading "null" (most likey because this code: String relationship = null;). I assume this means that none of my if else statements were satisfied and I really dont know why.
Also important to point out is that if I click submit without clicking any radio button (the button stays on "family"), it reads null. If I click a button once it works perfectly reading the string I intended. But if I click another button afterwards and click submit again, the string goes back to "null".
I know its lengthy but I would really appreciate any help because I am lost.
P.S. some parts of my code are repetitive because I was playing around trying to fix the problem.

I suggest you handle your action events separately, for example:
family.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
familyActionPerformed(evt);
}
});
Then implement familyActionPerformed(evt):
private void familyActionPerformed(java.awt.event.ActionEvent evt) {
// every click on family radio button causes the code here to be executed
relation1 = true;
}
Also write an event handler for the button you click, like this:
submitButtonActionPerformed(java.awt.event.ActionEvent evt) {
// Here test the state of each radio button
relation1 = family.isSelected();
relation2 = friend.isSelected();
relation3 = relative.isSelected();
relation4 = friendFriend.isSelected();
}
MORE EDIT:
Doing what you're doing with NetBeans should be very easy. Here are tutorials that will clear it all up for you:
Tutorial 1
Tutorial 2
I explain the solution again:
Using 'family' button as an example, in your constructor where you have created and initialised your GUI components do this:
JRadioButton family = new JRadioButton();
// do any other thing you want to do to this button and finally..
family.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
familyActionPerformed(evt);
}
});
JButton submit = new JButton("Submit");
submit.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
submitActionPerformed(evt);
}
});
Then somewhere create these methods:
private void familyActionPerformed(java.awt.event.ActionEvent evt){
// each time family is selected, you code processes the lines below:
...
}
private void submiteActionPerformed(java.awt.event.ActionEvent evt){
relation1 = family.isSelected();
relation2 = friend.isSelected();
relation3 = relative.isSelected();
relation4 = friendFriend.isSelected();
}
Do something similar for the rest of the RadioButtons.

I think that you're making things way too complex for yourself. If all you want is the String of the JRadioButton pressed, then use the ButtonGroup to get it for you. It can return the ButtonModel of the selected JRadioButton (if any one was selected), and from that you can extract the actionCommand String, although you'll have to remember to set this when you create your JRadioButton.
For example:
import java.awt.event.ActionEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class JRadioExample extends JPanel {
private static final String[] RADIO_TITLES = { "Family", "Friend",
"Relative", "Friend or Relative" };
private ButtonGroup btnGrp = new ButtonGroup();
public JRadioExample() {
for (int i = 0; i < RADIO_TITLES.length; i++) {
JRadioButton rBtn = new JRadioButton(RADIO_TITLES[i]);
rBtn.setActionCommand(RADIO_TITLES[i]); // ***** this is what needs to
// be set
btnGrp.add(rBtn);
add(rBtn);
}
add(new JButton(new BtnAction("Get Chosen Selection")));
}
private class BtnAction extends AbstractAction {
public BtnAction(String name) {
super(name);
}
#Override
public void actionPerformed(ActionEvent evt) {
ButtonModel model = btnGrp.getSelection();
if (model != null) {
String actionCommand = model.getActionCommand();
System.out.println("Selected Button: " + actionCommand);
} else {
System.out.println("No Button Selected");
}
}
}
private static void createAndShowGui() {
JRadioExample mainPanel = new JRadioExample();
JFrame frame = new JFrame("JRadioExample");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

JComboBox not showing arrow

I have been searching this site and google for a solution to my problem, and I can't find anything. I think it's supposed to just work; however, it doesn't. The arrow icon for my JComboBox doesn't show up, and I can't find anywhere to set its visibility to true.
Here's my code:
public class Driver implements ActionListener {
private JTextField userIDField;
private JTextField[] documentIDField;
private JComboBox repository, environment;
private JButton close, clear, submit;
private JFrame window;
public Driver()
{
window = makeWindow();
makeContents(window);
window.repaint();
}
private JFrame makeWindow()
{
JFrame window = new JFrame("");
window.setSize(500,300);
window.setLocation(50,50);
window.getContentPane().setLayout(null);
window.setResizable(false);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setVisible(true);
return window;
}
private void makeContents(JFrame w)
{
makeDropDowns(w);
w.repaint();
}
private void makeDropDowns(JFrame w)
{
String[] repositoryArray = {"Click to select", "NSA", "Finance", "Test"};
repository = new JComboBox(repositoryArray);
repository.setSelectedIndex(0);
repository.addActionListener(this);
repository.setSize(150,20);
repository.setLocation(175,165);
repository.setEditable(false);
w.add(repository);
String[] environmentArray = {"Click to select", "Dev", "Test", "Qual"};
environment = new JComboBox(environmentArray);
environment.setSelectedIndex(0);
environment.addActionListener(this);
environment.setSize(150,20);
environment.setLocation(175,195);
//environment.setEditable(false);
w.add(environment,0);
}
public void actionPerformed(ActionEvent e)
{
String repositoryID = "null", environmentID = "null";
if (e.getSource() == repository)
{
repositoryID = (String)repository.getSelectedItem();
}
if(e.getSource() == environment)
{
environmentID = (String)environment.getSelectedItem();
}
}
}
Here's a link to a picture of the problem:
If anyone could help that would be awesome.

It doesn't appear to be the issue you were suffering from, but I found this post due to the same resulting issue of the arrow disappearing.
In my case it was due to me mistakenly using .removeAll() on the JComboBox rather than .removeAllItems() when I was attempting to empty and then reuse the JComboBox after a refresh of the data I was using. Just thought I'd include it as an answer in case someone else comes across this thread for similar reasons.

The code you show works, but it looks like you're fighting the enclosing container's default layout. Here, ComboTest is a JPanel which defaults to FlowLayout.
Addendum: In general, do not use absolute positioning, as shown in your update. I've changed the example to use GridLayout; comment out the setLayout() call to see the default, FlowLayout.
import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
/**
* #see https://stackoverflow.com/a/10824504/230513
*/
public class ComboTest extends JPanel {
private JComboBox repository = createCombo(new String[]{
"Click to select", "NSA", "Finance", "Test"});
private JComboBox environment = createCombo(new String[]{
"Click to select", "Dev", "Test", "Qual"});
public ComboTest() {
this.setLayout(new GridLayout(0, 1));
this.add(repository);
this.add(environment);
}
private JComboBox createCombo(String[] data) {
final JComboBox combo = new JComboBox(data);
combo.setSelectedIndex(1);
combo.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
System.out.println(e.getActionCommand()
+ ": " + combo.getSelectedItem().toString());
}
});
return combo;
}
private void display() {
JFrame f = new JFrame("ComboTest");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(this);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new ComboTest().display();
}
});
}
}

I had the same issue. I fixed it by revalidating and repainting the panel with the following code :
myPanel.revalidate();
myPanel.repaint();

Maybe a little late, but for those who are still looking for an easy and fail-safe way to use the JComboBox can use this:
public class FixedJComboBox<E>
extends JComboBox<E> {
// Copied constructors
public FixedJComboBox() {
super();
}
public FixedJComboBox(ComboBoxModel<E> aModel) {
super(aModel);
}
public FixedJComboBox(E[] items) {
super(items);
}
public FixedJComboBox(Vector<E> items) {
super(items);
}
#Override
public void setBounds(int x, int y, int width, int height) {
super.setBounds(x, y, width, height);
// The arrow is the first (and only) component
// that is added by default
Component[] comps = getComponents();
if (comps != null && comps.length >= 1) {
Component arrow = comps[0];
// 20 is the default width of the arrow (for me at least)
arrow.setSize(20, height);
arrow.setLocation(width - arrow.getWidth(), 0);
}
}
}
As described here, the bug is caused by incorrectly setting both the location and the size of the arrow to (0,0), followed by some repainting issues. By simply overriding the setBounds() function, the arrow is always corrected after the UI/layout manager has wrongly updated the arrow.
Also, since new components are added after the old ones (i.e. higher index), the arrow will always be at the first element in the array (assuming you don't remove and re-add the arrow).
The disadvantage is of this class is that the width of the arrow is now determined by a constant instead of the UI/layout manager.

Communication between JOptionPane buttons and a custom panel

I have made a multiple input dialog by building a JPanel with the fields I want and adding it to a JOption pane
JMainPanel mainPanel = new JMainPanel(mensaje, parametros, mgr);
int i = JOptionPane.showOptionDialog(null, mainPanel, "Sirena",
JOptionPane.DEFAULT_OPTION, JOptionPane.PLAIN_MESSAGE, null,
new String[] {"Aceptar", "Cancelar"}, "Aceptar");
However I'm having trouble with the buttons, because some of the fields are required. How can I make the "Ok" button to be enabled once every required field is up, or making the click on the button to make the validations and do not close the pane until every required field is filled?
From the Java API, I found this:
options - an array of objects indicating the possible choices the user
can make; if the objects are components, they are rendered properly;
non-String objects are rendered using their toString methods; if this
parameter is null, the options are determined by the Look and Feel
So, can't I pass custom buttons as parameter?
Looks like I will have to make my own JDialog? for which case, I don't know how to make it return an int just like JOptionPane does, any recommended tutorial?
In the example options is {"Aceptar", "Cancelar"} which are the displayed buttons,
PS. I have full controll over the fields I added to the JPanel.
This is a screenshot of the JOptionPane:

I don't think that you can de-activate a JOptionPane's selections buttons, but one way to still use the JOptionPane is to simply re-display it if the required fields have not been set. You could display an error message JOptionPane first describing the error, and then display a new JOptionPane that holds the same JPanel as its second parameter -- so that the data already entered has not been lost. Otherwise, you may want to create your own JDialog which by the way isn't that hard to do.
Edit
I'm wrong. You can enable and disable the dialog buttons if you use a little recursion.
For example:
import java.awt.Component;
import java.awt.Container;
import java.awt.event.*;
import java.util.HashSet;
import java.util.Set;
import javax.swing.*;
public class Foo extends JPanel {
private static final String[] DIALOG_BUTTON_TITLES = new String[] { "Aceptar", "Cancelar" };
private JCheckBox checkBox = new JCheckBox("Buttons Enabled", true);
private Set<AbstractButton> exemptButtons = new HashSet<AbstractButton>();
public Foo() {
JButton exemptBtn = new JButton("Exempt Button");
JButton nonExemptBtn = new JButton("Non-Exempt Button");
add(checkBox);
add(exemptBtn);
add(nonExemptBtn);
exemptButtons.add(checkBox);
exemptButtons.add(exemptBtn);
checkBox.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent evt) {
allBtnsSetEnabled(checkBox.isSelected());
}
});
}
private void allBtnsSetEnabled(boolean enabled) {
JRootPane rootPane = SwingUtilities.getRootPane(checkBox);
if (rootPane != null) {
Container container = rootPane.getContentPane();
recursiveBtnEnable(enabled, container);
}
}
private void recursiveBtnEnable(boolean enabled, Container container) {
Component[] components = container.getComponents();
for (Component component : components) {
if (component instanceof AbstractButton && !exemptButtons.contains(component)) {
((AbstractButton) component).setEnabled(enabled);
} else if (component instanceof Container) {
recursiveBtnEnable(enabled, (Container) component);
}
}
}
public int showDialog() {
return JOptionPane.showOptionDialog(null, this, "Sirena",
JOptionPane.DEFAULT_OPTION, JOptionPane.PLAIN_MESSAGE, null,
DIALOG_BUTTON_TITLES, "Aceptar");
}
private static void createAndShowGui() {
Foo foo = new Foo();
int result = foo.showDialog();
System.out.println(DIALOG_BUTTON_TITLES[result]);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
This code uses listeners to check the state of a JCheckBox, but you can have listeners (DocumentListeners) listening to text field documents if you desire to know if they have data or not. The code then gets the JRootPane that holds the JCheckBox, then the root pane's contentPane, and all components of the dialog are held by this. It then recurses through all the components held by the dialog. If a component is a Container, it recurses through that container. If the component is an AbstractButton (such any JButton or checkbox), it enables or disables -- except for buttons held in the exempt buttons set.
A better example with document listeners
import java.awt.*;
import java.awt.event.*;
import java.util.HashSet;
import java.util.Set;
import javax.swing.*;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
public class Foo2 extends JPanel {
private static final String[] DIALOG_BUTTON_TITLES = new String[] {
"Aceptar", "Cancelar" };
private static final int FIELD_COUNT = 10;
private Set<AbstractButton> exemptButtons = new HashSet<AbstractButton>();
private JTextField[] fields = new JTextField[FIELD_COUNT];
public Foo2() {
setLayout(new GridLayout(0, 5, 5, 5));
DocumentListener myDocListener = new MyDocumentListener();
for (int i = 0; i < fields.length; i++) {
fields[i] = new JTextField(10);
add(fields[i]);
fields[i].getDocument().addDocumentListener(myDocListener);
}
// cheating here
int timerDelay = 200;
Timer timer = new Timer(timerDelay , new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
checkDocsForText();
}
});
timer.setRepeats(false);
timer.setInitialDelay(timerDelay);
timer.start();
}
private void checkDocsForText() {
for (JTextField field : fields) {
if (field.getText().trim().isEmpty()) {
allBtnsSetEnabled(false);
return;
}
}
allBtnsSetEnabled(true);
}
private void allBtnsSetEnabled(boolean enabled) {
JRootPane rootPane = SwingUtilities.getRootPane(this);
if (rootPane != null) {
Container container = rootPane.getContentPane();
recursiveBtnEnable(enabled, container);
}
}
private void recursiveBtnEnable(boolean enabled, Container container) {
Component[] components = container.getComponents();
for (Component component : components) {
if (component instanceof AbstractButton && !exemptButtons.contains(component)) {
((AbstractButton) component).setEnabled(enabled);
} else if (component instanceof Container) {
recursiveBtnEnable(enabled, (Container) component);
}
}
}
public int showDialog() {
return JOptionPane.showOptionDialog(null, this, "Sirena",
JOptionPane.DEFAULT_OPTION, JOptionPane.PLAIN_MESSAGE, null,
DIALOG_BUTTON_TITLES, "Aceptar");
}
private class MyDocumentListener implements DocumentListener {
public void removeUpdate(DocumentEvent arg0) {
checkDocsForText();
}
public void insertUpdate(DocumentEvent arg0) {
checkDocsForText();
}
public void changedUpdate(DocumentEvent arg0) {
checkDocsForText();
}
}
private static void createAndShowGui() {
Foo2 foo = new Foo2();
int result = foo.showDialog();
if (result >= 0) {
System.out.println(DIALOG_BUTTON_TITLES[result]);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

I suggest you to define some properties into your JPanel extended class, and use PropertyChangeListener to listen the occured changes and enable/disable relative buttons.
Here's an article.
Another issue maybe finding the ok/cancel buttons in the hierarchy of components, since the JDialog is created through JOptionPane and you haven't a reference to the buttons. Here's a useful thread .
You can add a property to a JComponent using putClientProperty method.
When changes occurs to a given property a PropertyChanged event is raised.
So in your example you can define a boolean property indicating that required that are inserted into the JDialog. Then add a PropertyChangeListener that when is notified enable/disable the ok button.

JDialog repaint after JList modification

I have a JDialog dlg, created by a JFrame frm, that contains a JList list.
When I modify the list (through the ListModel), the list itself is repainted but not the JDialog.
This means that, if I delete a line, the list remains with an empty line while if I add a line, this new line won't be shown (because there is no space in the dialog) until I manually force repainting of dlg (doubleclicking in frm).
Following advices in this post :
How to make repaint for JDialog in Swing?
and in this post:
Force repaint after button click
I tried to call, from my controller class (which is where updates to list are made), the following line:
SwingUtilities.getWindowAncestor(dlg).repaint();
but it didn't work.
I also tried:
dlg.repaint();
No luck either...
Any clue?
Thank you very much.
EDIT:
The organization of my classes is as follows:
a controller class that contains a reference to the main JFrame, frm.
I also extended JDialog into MyDialog, which contains a JList.
When a doubleclick on frm is detected, I show the instance of MyDialog (or create, if it is the first time I show it) and the JList is filled with the data passed to the DefaultListModel. MyDialog is painted so that the list has only the space that it needs.
Now, when a specific event is detected by the controller, I get the specific MyDialog, get the ListModel from JList and update it. Here the JList is indeed updated, but Dialog remains the same.
I use a code like this:
MyDialog dlg = group.getDlg();
if(dlg != null){
DefaultListModel listModel = ((DefaultListModel) dlg.getMyJList().getModel());
listModel.addElement(idStock);
SwingUtilities.getWindowAncestor(dlg).repaint();
}
This doesn't repaint dlg.
I also tried:
SwingUtilities.getWindowAncestor(dlg.getMyJList()).repaint();
but it doesn't work.
I checked with the debugger that the lines are actually executed.
I don't have much more code to show, really.....

I think that you going wrong way, define DefaultListModel that accesible throught all Java methods and Classes, this Model would holds your Objects, then put JList to the JDialog or JOptionPane, for example
import java.awt.*;
import java.awt.event.ActionEvent;
import javax.swing.*;
// based on #trashgod code
/** #see http://stackoverflow.com/questions/5759131 */
// http://stackoverflow.com/questions/8667719/jdialog-repaint-after-jlist-modification
public class ListDialog {
private static final int N = 12;
private JDialog dlg = new JDialog();
private DefaultListModel model = new DefaultListModel();
private JList list = new JList(model);
private JScrollPane sp = new JScrollPane(list);
private int count;
public ListDialog() {
list.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
JPanel panel = new JPanel();
panel.add(new JButton(new AbstractAction("Add") {
private static final long serialVersionUID = 1L;
#Override
public void actionPerformed(ActionEvent e) {
append();
if (count <= N) {
list.setVisibleRowCount(count);
dlg.pack();
}
}
}));
panel.add(new JButton(new AbstractAction("Remove") {
private static final long serialVersionUID = 1L;
#Override
public void actionPerformed(ActionEvent e) {
int itemNo = list.getSelectedIndex();
if (itemNo > -1) {
removeActionPerformed(e, itemNo);
}
}
}));
for (int i = 0; i < N - 2; i++) {
this.append();
}
list.setVisibleRowCount(N - 2);
dlg.add(sp, BorderLayout.CENTER);
dlg.add(panel, BorderLayout.SOUTH);
dlg.pack();
dlg.setLocationRelativeTo(null);
dlg.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
dlg.setVisible(true);
}
private void removeActionPerformed(ActionEvent e, int itemNo) {
System.out.println("made_list's model: " + list.getModel());
System.out.println("Model from a fresh JList: " + new JList().getModel());
model = (DefaultListModel) list.getModel();
if (model.size() > 0) {
if (itemNo > -1) {
model.remove(itemNo);
}
}
}
private void append() {
model.addElement("String " + String.valueOf(++count));
list.ensureIndexIsVisible(count - 1);
}
public static void main(String[] a_args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
ListDialog pd = new ListDialog();
}
});
}
}