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JList is not updated within a worker thread model

Withing a worker thread, Java runs my methods and in one of the methods, a JList is filled. Problem is that, when I run the program, the JList is not getting updated however by debugging with Netbeans, the list gets updated properly!!
How that can be justified?
The code looks like
public class TheFrame extends javax.swing.JFrame {
public TheFrame() {
theFile = new ExcelFile();
initComponents();
}
#SuppressWarnings("unchecked")
private void initComponents() {
model = new DefaultListModel();
effectList = new javax.swing.JList<>();
effectList.setModel(model);
pack();
}
/* worker threads is here */
private ExcelFile theFile;
private DefaultListModel<String> model;
private javax.swing.JList<String> effectList;
}
The implementation of worker is
private void Load(JFileChooser fc, int i)
{
/* i is an identifier which shows which button has been pressed */
/* stuffs for creating a please wait window */
SwingWorker<Void, Void> worker = new SwingWorker<Void, Void>() {
#Override
protected Void doInBackground() throws InterruptedException {
if ( i == 1 ) {
List< String > ls = theFile.updateEffectList();
for (int i = 0; i < ls.size(); i++) {
// The following line works fine in the debug mode
// but By running the project, it will be empty
model.addElement(ls.get(i));
}
effectList.setVisible(true);
}
return null;
}
#Override
protected void done() {
loading.dispose(); // this is the please wait window
}
};
worker.addPropertyChangeListener(new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
//System.out.println(evt.getPropertyName());
Object value = evt.getNewValue();
if (value instanceof SwingWorker.StateValue) {
SwingWorker.StateValue state = (SwingWorker.StateValue) value;
switch (state) {
case DONE: {
try {
worker.get();
} catch (InterruptedException | ExecutionException ex) {
JOptionPane.showMessageDialog(null, "Failed");
ex.printStackTrace();
}
}
break;
}
}
}
});
worker.execute();
loading.setVisible(true); // this is the please wait window
}
There are some discussions about that but I didn't got my answer there.

Here a Minimal, Complete, and Verifiable example (maybe not that minimal)!
I also urge you to study the SwingWorker's documentation and see the Swing's Threading Policy.
import java.awt.BorderLayout;
import java.awt.Cursor;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ExecutionException;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;
public class TheFrame {
public static void main(String[] args) {
new TheFrame();
}
private JFrame frame;
private JList<String> list;
private DefaultListModel<String> model;
private JButton load;
private TheFrame() {
SwingUtilities.invokeLater(this::initGUI);
}
private void initGUI() {
// runs on EDT
model = new DefaultListModel<>();
list = new JList<>(model);
// for testing
load = new JButton("Load");
load.addActionListener(ev -> load());
frame = new JFrame();
frame.setLayout(new BorderLayout());
frame.add(new JScrollPane(list), BorderLayout.CENTER);
frame.add(load, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setSize(400, 300);
frame.validate();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private void load() {
// runs on EDT
frame.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
SwingWorker<Void, String> worker = new SwingWorker<Void, String>() {
#Override
protected Void doInBackground() throws Exception {
// runs on worker Thread
List<String> ls = updateList();
for (String string : ls) {
simulateDelay(200);
publish(string);
}
return null;
}
#Override
protected void process(List<String> chunks) {
// runs on EDT
for (String string : chunks) {
model.addElement(string);
}
}
#Override
protected void done() {
// runs on EDT
try {
get(); // check for Exceptions
} catch (InterruptedException | ExecutionException ex) {
ex.printStackTrace();
} finally {
frame.setCursor(Cursor.getDefaultCursor());
}
}
};
worker.execute();
}
// generate some sample data
private List<String> updateList() {
simulateDelay(500);
List<String> data = Arrays.asList("a", "b", "c", "d", "e", "f", "g");
Collections.shuffle(data); // just fun.. erh, testing
return data;
}
// for testing only, do not use this in production/real code
private static void simulateDelay(long delay) {
try {
Thread.sleep(delay);
} catch (#SuppressWarnings("unused") InterruptedException ignored) {
}
}
}

Java Jpanel Repaint/update probleme

i have a problem with the method Repaint of my jpanel.
I'm trying to make a "Racing game" with the Java Swing and by following the MVC architecture :
i have 5 classes :
Main : runs the MVC
public class Main {
private static Model model;
private static View view;
private static Controller controller;
public static void main(String[] args) {
model = new Model();
view = new View();
controller = new Controller();
model.addObserver(view);
controller.addModule(model);
controller.addView(view);
view.addContoller(controller);
}
}
Model :
import java.util.ArrayList;
import java.util.Observable;
public class Model extends Observable{
private ArrayList<Car> cars;// List of cars
public Model() {
cars = new ArrayList<Car>();
cars.add(new Car(this,0, 50));
cars.add(new Car(this,0, 50));
cars.add(new Car(this,0, 50));
}
public void startCar(int i){
//i is the index of the selected element in the checkbox
//if i==0 then the selected element is "All cars" else is a specific car
if(i>0)
cars.get(i-1).start();
else{
for(int j=0;j<cars.size();j++)
cars.get(j).start();
}
}
public void speedUpCar(int i) {
if(i>0)
cars.get(i-1).incVitess();
else{
for(int j=0;j<cars.size();j++)
cars.get(j).incVitess();
}
}
public void notifyView(){
setChanged();
notifyObservers(cars);
}
public void speedDownCar(int i) {
if(i>0)
cars.get(i-1).decVitess();
else{
for(int j=0;j<cars.size();j++)
cars.get(j).decVitess();
}
}
public void stopCar(int i) {
if(i>0)
cars.get(i-1).stop();
else{
for(int j=0;j<cars.size();j++)
cars.get(j).stop();
}
}
}
the View :
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.ArrayList;
import java.util.Observable;
import java.util.Observer;
import java.util.Vector;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class View implements Observer {
private JFrame fen;
private JPanel btnPanel,panel;
private JButton play,speedUp,speedDown,stop;
private JComboBox<String> listeCar;
private boolean test = false;
public View() {
fen = new JFrame();
fen.setTitle("Car Racing");
fen.setSize(900, 400);
fen.setLocationRelativeTo(null);
fen.setResizable(false);
Vector<String> v = new Vector<String>();
v.add("All cars");v.add("car 1");v.add("car 2");v.add("car 3");
listeCar = new JComboBox<String>(v);
play = new JButton("Play");
speedUp = new JButton("+");
speedDown = new JButton("-");
stop = new JButton("stop");
panel = new JPanel(new GridLayout(3,1));
btnPanel = new JPanel();
btnPanel.add(listeCar);
btnPanel.add(play);
btnPanel.add(speedUp);
btnPanel.add(speedDown);
btnPanel.add(stop);
Container c = fen.getContentPane();
c.setLayout(new BorderLayout());
c.add(btnPanel, BorderLayout.SOUTH);
c.add(panel, BorderLayout.CENTER);
fen.setVisible(true);
fen.addWindowListener(new WindowAdapter() {
#Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
}
public void addContoller(Controller controller){
play.addActionListener(controller);
speedUp.addActionListener(controller);
speedDown.addActionListener(controller);
stop.addActionListener(controller);
}
#Override
public void update(Observable arg0, Object c) {
ArrayList<Car> cars = (ArrayList<Car>)c;
for(int i=0;i<cars.size();i++){
Car car = cars.get(i);
if(!test){ // if its the first tima, add the cars to the panel
panel.add(car);
}else{
car.repaint(); // << the Problem is HERE
}
}
test = true;
}
public JButton getPlay() {
return play;
}
public JButton getSpeedUp() {
return speedUp;
}
public JButton getSpeedDown() {
return speedDown;
}
public JButton getStop() {
return stop;
}
public JComboBox<String> getListeCar() {
return listeCar;
}
}
The controller:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Controller implements ActionListener{
private Model model;
private View view;
public Controller() {
}
public void addModule(Model m) {
model = m;
model.notifyView();
}
public void addView(View v){
view = v;
}
#Override
public void actionPerformed(ActionEvent e) {
if(e.getSource() == view.getPlay()){
model.startCar(view.getListeCar().getSelectedIndex());
}else if(e.getSource() == view.getSpeedUp()){
model.speedUpCar(view.getListeCar().getSelectedIndex());
}else if(e.getSource() == view.getSpeedDown()){
model.speedDownCar(view.getListeCar().getSelectedIndex());
}else if(e.getSource() == view.getStop()){
model.stopCar(view.getListeCar().getSelectedIndex());
}
}
}
The car class :
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JPanel;
public class Car extends JPanel{
private int id,x,y,vitess;
private Thread thread;
private Model model;
private boolean start = true;
private boolean forward = true;
private Color color;
private boolean threadStarted = false;
private BufferedImage bg; // background image
public Car(Model model,int x,int y) {
this.x =x;
this.y = y;
vitess = 7;
this.model = model;
try {
bg = ImageIO.read(new File("road.png"));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
color = changeColor(); // Random color
thread = new Thread(new CarThread(this));
start();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(bg, 0, 0, null);
g.setColor(color);
g.fillRect(x, y, 100, 50); // the car is a simple rectangle
}
public void start() {
start = true;
if(!threadStarted){
threadStarted = true;
thread.start();
}else{
thread.resume();
}
}
public void move(){
System.out.println("X:"+x);
if(forward){
if(x<this.getWidth()){
x+=2;
}else{
color = changeColor();
forward = false;
}
}else{
if(x>0){
x-=2;
}else{
color = changeColor();
forward = true;
}
}
model.notifyView();
}
private Color changeColor() {
int r = (int)(Math.random()*255);
int g = (int)(Math.random()*255);
int b = (int)(Math.random()*255);
return new Color(r,g,b);
}
public void stop(){
start = false;
thread.suspend();
}
public void incVitess(){
if(vitess>1)
vitess--;
}
public void decVitess(){
if(vitess<6)
vitess++;
}
public int getId() {
return id;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public int getVitess() {
return vitess;
}
public boolean getStart(){
return start;
}
public void setStart(boolean m){
this.start = m;
}
public Color getColor(){
return color;
}
}
CarThraed class:
public class CarThread implements Runnable{
private Car car;
public CarThread(Car car) {
this.car = car;
}
#Override
public void run() {
while(car.getStart()){
car.move();
try {
Thread.sleep(car.getVitess());
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
if you run the project you will note that the cars does not reach the end of the frame, even if used:
if(x<this.getWidth()) x++;
but when i replace
car.repaint(); // << the Problem is HERE
with
car.update(car.getGraphics()); // << the Problem is HERE
the cars can now reach the end of the Frame, but the buttons in the btnJpanel disappear
image with repaint here
image with update here
thank you in advance

I can't say that I've read all your code, but your model never notifies the view. I mean nowhere inside of the model class's code is the notifyView() method called. It should be the model's responsibility to call this whenever its state is changed.
Note that this:
car.update(car.getGraphics()); // << the Problem is HERE
Should not be used as the Graphics obtained is not stable.
Also, your model holds view components, an ArrayList of Car, a class that extends JPanel, another thing that should never occur as the model should be completely ignorant of the view, with the exception being that it knows that some things may be listening to it, and it needs to notify those things, and that's it. Instead your Model should hold an ArrayList of non-view, non-JPanel logical Car objects.
Edit
You state:
In the model i have the method: public void notifyView() which is called by the car's method public void Move() , That means whenever the thread calls the move method of the car, it calls the notifyView of the model
No, the Car should not be calling this method -- only the model itself should call this when its state is changed.
Also, I see that you've got very dangerous code using Thread#suspend() and Thread#resume() method calls. These methods have been deprecated as they've been found to be dangerous. To find out why, please check the API for Thread as well as this useful article. You will most definitely want to avoid their use.
Suggestions
Make Car a logical non-GUI class that knows its position and can have its position changed.
Override your drawing JPanels protected void paintComonent(Graphics g) method and use the Car information from the model to draw the Cars. In other words, use the state of the model to affect the state of the view.
Use a Swing Timer instead of a background thread, to change your Car positions.
Have the model and only the model call the notifyView method when its state has been changed.
Edit
Your main bug is here:
class Car extends JPanel {
private int id, x, y, vitess;
//....
public int getX() {
return x;
}
public int getY() {
return y;
}
You're inadvertently overriding the Car JPanel's getX and getY methods, messing up the location of these components. This is another reason to avoid overriding Swing components unless necessary -- to avoid these hidden side effects.
Get rid of or rename these methods.

How to show autocomplete as I type in JTextArea?

I need to show suggestions (autocomplete) as the user types in a JTextArea, kind of like cell phone T9.
I don't know how to do this in myTextAreaKeyTyped() event.
This app is a typing helper. It shows variants of characters non-present on the keyboard.
E.G. You press 'A', it shows Â:1, Á:2 ,À:3… 'A' will be replaced if you press 1,2 or 3.
It's already done, but the variants are shown in a JLabel at the bottom of my JFrame, because I don't know how to do this.
Can you please help me out? Thanks in advance.

Here is a snippet to get yourself inspired. You will probably need to reorganize a bit the code to make it more maintainable, but it should give you the gist.
Basically, we listen for key events (I don't find it relevant to listen to document events, for example if the user pastes some text, I don't want the suggestion panel to appear), and when the caret has at least 2 characters behind, we make some suggestions, using a popupmenu containing a JList of suggestions (here suggestions are really not meaningful, but it would not be too hard to bind this to a dictionnary). As for the shortcuts you are mentionning, it should not be too hard to do so.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Point;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JPopupMenu;
import javax.swing.JTextArea;
import javax.swing.ListSelectionModel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.text.BadLocationException;
public class Test {
public class SuggestionPanel {
private JList list;
private JPopupMenu popupMenu;
private String subWord;
private final int insertionPosition;
public SuggestionPanel(JTextArea textarea, int position, String subWord, Point location) {
this.insertionPosition = position;
this.subWord = subWord;
popupMenu = new JPopupMenu();
popupMenu.removeAll();
popupMenu.setOpaque(false);
popupMenu.setBorder(null);
popupMenu.add(list = createSuggestionList(position, subWord), BorderLayout.CENTER);
popupMenu.show(textarea, location.x, textarea.getBaseline(0, 0) + location.y);
}
public void hide() {
popupMenu.setVisible(false);
if (suggestion == this) {
suggestion = null;
}
}
private JList createSuggestionList(final int position, final String subWord) {
Object[] data = new Object[10];
for (int i = 0; i < data.length; i++) {
data[i] = subWord + i;
}
JList list = new JList(data);
list.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 1));
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
list.setSelectedIndex(0);
list.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
if (e.getClickCount() == 2) {
insertSelection();
}
}
});
return list;
}
public boolean insertSelection() {
if (list.getSelectedValue() != null) {
try {
final String selectedSuggestion = ((String) list.getSelectedValue()).substring(subWord.length());
textarea.getDocument().insertString(insertionPosition, selectedSuggestion, null);
return true;
} catch (BadLocationException e1) {
e1.printStackTrace();
}
hideSuggestion();
}
return false;
}
public void moveUp() {
int index = Math.min(list.getSelectedIndex() - 1, 0);
selectIndex(index);
}
public void moveDown() {
int index = Math.min(list.getSelectedIndex() + 1, list.getModel().getSize() - 1);
selectIndex(index);
}
private void selectIndex(int index) {
final int position = textarea.getCaretPosition();
list.setSelectedIndex(index);
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
textarea.setCaretPosition(position);
};
});
}
}
private SuggestionPanel suggestion;
private JTextArea textarea;
protected void showSuggestionLater() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
showSuggestion();
}
});
}
protected void showSuggestion() {
hideSuggestion();
final int position = textarea.getCaretPosition();
Point location;
try {
location = textarea.modelToView(position).getLocation();
} catch (BadLocationException e2) {
e2.printStackTrace();
return;
}
String text = textarea.getText();
int start = Math.max(0, position - 1);
while (start > 0) {
if (!Character.isWhitespace(text.charAt(start))) {
start--;
} else {
start++;
break;
}
}
if (start > position) {
return;
}
final String subWord = text.substring(start, position);
if (subWord.length() < 2) {
return;
}
suggestion = new SuggestionPanel(textarea, position, subWord, location);
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
textarea.requestFocusInWindow();
}
});
}
private void hideSuggestion() {
if (suggestion != null) {
suggestion.hide();
}
}
protected void initUI() {
final JFrame frame = new JFrame();
frame.setTitle("Test frame on two screens");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel(new BorderLayout());
textarea = new JTextArea(24, 80);
textarea.setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY, 1));
textarea.addKeyListener(new KeyListener() {
#Override
public void keyTyped(KeyEvent e) {
if (e.getKeyChar() == KeyEvent.VK_ENTER) {
if (suggestion != null) {
if (suggestion.insertSelection()) {
e.consume();
final int position = textarea.getCaretPosition();
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
try {
textarea.getDocument().remove(position - 1, 1);
} catch (BadLocationException e) {
e.printStackTrace();
}
}
});
}
}
}
}
#Override
public void keyReleased(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_DOWN && suggestion != null) {
suggestion.moveDown();
} else if (e.getKeyCode() == KeyEvent.VK_UP && suggestion != null) {
suggestion.moveUp();
} else if (Character.isLetterOrDigit(e.getKeyChar())) {
showSuggestionLater();
} else if (Character.isWhitespace(e.getKeyChar())) {
hideSuggestion();
}
}
#Override
public void keyPressed(KeyEvent e) {
}
});
panel.add(textarea, BorderLayout.CENTER);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (UnsupportedLookAndFeelException e) {
e.printStackTrace();
}
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Test().initUI();
}
});
}
}

jcombobox filter in java - Look and feel independent

I have a simple JComboBox filter code like this :
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
public class FilterComboBox extends JComboBox {
private List<String> array;
public FilterComboBox(List<String> array) {
super(array.toArray());
this.array = array;
this.setEditable(true);
final JTextField textfield = (JTextField) this.getEditor().getEditorComponent();
textfield.addKeyListener(new KeyAdapter() {
public void keyReleased(KeyEvent ke) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
comboFilter(textfield.getText());
}
});
}
});
}
public void comboFilter(String enteredText) {
List<String> filterArray= new ArrayList<String>();
for (int i = 0; i < array.size(); i++) {
if (array.get(i).toLowerCase().contains(enteredText.toLowerCase())) {
filterArray.add(array.get(i));
}
}
if (filterArray.size() > 0) {
this.setModel(new DefaultComboBoxModel(filterArray.toArray()));
this.setSelectedItem(enteredText);
this.showPopup();
}
else {
this.hidePopup();
}
}
/* Testing Codes */
public static List<String> populateArray() {
List<String> test = new ArrayList<String>();
test.add("");
test.add("Mountain Flight");
test.add("Mount Climbing");
test.add("Trekking");
test.add("Rafting");
test.add("Jungle Safari");
test.add("Bungie Jumping");
test.add("Para Gliding");
return test;
}
public static void makeUI() {
JFrame frame = new JFrame("Adventure in Nepal - Combo Filter Test");
FilterComboBox acb = new FilterComboBox(populateArray());
frame.getContentPane().add(acb);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public static void main(String[] args) throws Exception {
//UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
makeUI();
}
}
The performance of the combo filter is not so good but it is fine for few data set. My problem is - when I remove the comment UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); to change look and feel, the filter doesn't work. In WindowsLookAndFeel, the combo box only takes single character in it by replacing the previously entered character.
Can you please tell me whats going on? Manoj Shrestha's answer below helps in some way but , can you please provide some other suggestions to achieve combo box filter in Java?

Firstly you are creating new model everytime and then invoking show popup from code which leads to flickering etc. We can modify the model itself. Secondly you set the currently entered text as selected item which seems to have selectAll behavior as noted by others. I have modified the code as follows:
public void comboFilter(String enteredText) {
if (!this.isPopupVisible()) {
this.showPopup();
}
List<String> filterArray= new ArrayList<String>();
for (int i = 0; i < array.size(); i++) {
if (array.get(i).toLowerCase().contains(enteredText.toLowerCase())) {
filterArray.add(array.get(i));
}
}
if (filterArray.size() > 0) {
DefaultComboBoxModel model = (DefaultComboBoxModel) this.getModel();
model.removeAllElements();
for (String s: filterArray)
model.addElement(s);
JTextField textfield = (JTextField) this.getEditor().getEditorComponent();
textfield.setText(enteredText);
}
}
Hope it works for you.

very long answer, I think that exelent example about how different Look and Feel have got implemented methods in API and works
KeyListener isn't proper Listener for Swing JComponents, you really to have bothering with KeyBindings,
KeyListener is simple asynchronous,
JComboBox is Compound JComponent, then there is required override internal JComponents, all output from KeyListener must be wrapped into invokeLater(), notice I can create event from coumpond JComponents that twice invokeLater() doesn't returns expected output to the GUI, only Swing Timer with Swing Action can do that correctly, simple why to bothering wiht that example about wrong way,
code
import java.awt.Component;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.plaf.basic.BasicComboBoxRenderer;
public class ComboBoxHoverOver {
private JComboBox combo = new JComboBox();
public ComboBoxHoverOver() {
combo.setPrototypeDisplayValue("XXXXXXXXXXXXXXXXXXXXXX");
combo.setRenderer(new ComboToolTipRenderer(combo));
combo.addItemListener(new ItemListener() {
#Override
public void itemStateChanged(ItemEvent e) {
//System.out.println(combo.getSelectedItem().toString());
}
});
combo.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
//System.out.println(combo.getSelectedItem().toString());
}
});
combo.addItem("");
combo.addItem("Long text 4");
combo.addItem("Long text 3");
combo.addItem("Long text 2");
combo.addItem("Long text 1");
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(combo);
f.pack();
f.setVisible(true);
}
private class ComboToolTipRenderer extends BasicComboBoxRenderer {
private static final long serialVersionUID = 1L;
private JComboBox combo;
private JList comboList;
ComboToolTipRenderer(JComboBox combo) {
this.combo = combo;
}
#Override
public Component getListCellRendererComponent(JList list, Object value,
int index, boolean isSelected, boolean cellHasFocus) {
super.getListCellRendererComponent(
list, value, index, isSelected, cellHasFocus);
if (comboList == null) {
comboList = list;
KeyAdapter listener = new KeyAdapter() {
#Override
public void keyReleased(KeyEvent e) {
if (e.getKeyCode() == KeyEvent.VK_DOWN || e.getKeyCode() == KeyEvent.VK_UP) {
int x = 5;
int y = comboList.indexToLocation(comboList.getSelectedIndex()).y;
System.out.println(comboList.getSelectedIndex());
}
}
};
combo.addKeyListener(listener);
combo.getEditor().getEditorComponent().addKeyListener(listener);
}
if (isSelected) {
//System.out.println(value.toString());
}
return this;
}
}
public static void main(String[] args) throws ClassNotFoundException,
InstantiationException, IllegalAccessException, UnsupportedLookAndFeelException {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
java.awt.EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
ComboBoxHoverOver comboBoxHoverOver = new ComboBoxHoverOver();
}
});
}
}
JComboBox is Compound JComponent, then there is required override BasicComboBoxUI, please sorry I lazy to write and simulating too much longer code as code from first point
otherwise all effort from above two point are useless and contraproductive, nothing else, only DOT
please can someone to test follows code in *nix and apple OS X
from my Java6 WinXP compo (all important is hidden in the used methods, enless kudos for anonymous author from former Sun Microsystems)
Substance L&F
WindowsLookAndFeel L&F
Nimbus L&F
Metal L&F
from Java Classes
main
import java.awt.*;
import java.util.ArrayList;
import javax.swing.*;
import javax.swing.UIManager.LookAndFeelInfo;
import org.pushingpixels.substance.api.skin.SubstanceOfficeSilver2007LookAndFeel;
public class AutoCompleteTextField {
private static JFrame frame = new JFrame();
private ArrayList<String> listSomeString = new ArrayList<String>();
private Java2sAutoTextField someTextField = new Java2sAutoTextField(listSomeString);
private ArrayList<String> listSomeAnotherString = new ArrayList<String>();
private Java2sAutoComboBox someComboBox = new Java2sAutoComboBox(listSomeAnotherString);
public AutoCompleteTextField() {
listSomeString.add("-");
listSomeString.add("Snowboarding");
listSomeString.add("Rowing");
listSomeString.add("Knitting");
listSomeString.add("Speed reading");
listSomeString.add("Pool");
listSomeString.add("None of the above");
//
listSomeAnotherString.add("-");
listSomeAnotherString.add("XxxZxx Snowboarding");
listSomeAnotherString.add("AaaBbb Rowing");
listSomeAnotherString.add("CccDdd Knitting");
listSomeAnotherString.add("Eee Fff Speed reading");
listSomeAnotherString.add("Eee Fff Pool");
listSomeAnotherString.add("Eee Fff None of the above");
//
someTextField.setFont(new Font("Serif", Font.BOLD, 16));
someTextField.setForeground(Color.black);
someTextField.setBackground(Color.orange);
someTextField.setName("someTextField");
someTextField.setDataList(listSomeString);
//
someComboBox.setPrototypeDisplayValue("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
someComboBox.setFont(new Font("Serif", Font.BOLD, 16));
someComboBox.setForeground(Color.black);
someComboBox.setBackground(Color.YELLOW);
someComboBox.getEditor().selectAll();
someComboBox.getEditor().getEditorComponent().setBackground(Color.YELLOW);
((JTextField) someComboBox.getEditor().getEditorComponent()).setDisabledTextColor(Color.black);
someComboBox.setName("someComboBox");
someComboBox.setDataList(listSomeAnotherString);
//
frame.setLayout(new GridLayout(0, 1, 10, 10));
frame.add(someTextField);
frame.add(someComboBox);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocation(100, 100);
frame.pack();
frame.setVisible(true);
//
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
someTextField.setText("-");
someComboBox.getEditor().setItem(0);
someComboBox.getEditor().selectAll();
someTextField.grabFocus();
someTextField.requestFocus();
someTextField.setText(someTextField.getText());
someTextField.selectAll();
}
});
}
public static void main(String[] args) {
/*SwingUtilities.invokeLater(new Runnable() {
public void run() {
try {
UIManager.setLookAndFeel(new SubstanceOfficeSilver2007LookAndFeel());
SwingUtilities.updateComponentTreeUI(frame);
} catch (UnsupportedLookAndFeelException e) {
throw new RuntimeException(e);
}
}
});*/
/*try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
System.out.println(info.getName());
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (UnsupportedLookAndFeelException e) {
// handle exception
} catch (ClassNotFoundException e) {
// handle exception
} catch (InstantiationException e) {
// handle exception
} catch (IllegalAccessException e) {
// handle exception
}*/
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
AutoCompleteTextField aCTF = new AutoCompleteTextField();
}
});
}
}
AutoComboBox
import java.awt.event.ItemEvent;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.plaf.basic.BasicComboBoxEditor;
public class Java2sAutoComboBox extends JComboBox {
private static final long serialVersionUID = 1L;
private AutoTextFieldEditor autoTextFieldEditor;
private boolean isFired;
private class AutoTextFieldEditor extends BasicComboBoxEditor {
private Java2sAutoTextField getAutoTextFieldEditor() {
return (Java2sAutoTextField) editor;
}
AutoTextFieldEditor(java.util.List<String> list) {
editor = new Java2sAutoTextField(list, Java2sAutoComboBox.this);
}
}
public Java2sAutoComboBox(java.util.List<String> list) {
isFired = false;
autoTextFieldEditor = new AutoTextFieldEditor(list);
setEditable(true);
setModel(new DefaultComboBoxModel(list.toArray()) {
private static final long serialVersionUID = 1L;
#Override
protected void fireContentsChanged(Object obj, int i, int j) {
if (!isFired) {
super.fireContentsChanged(obj, i, j);
}
}
});
setEditor(autoTextFieldEditor);
}
public boolean isCaseSensitive() {
return autoTextFieldEditor.getAutoTextFieldEditor().isCaseSensitive();
}
public void setCaseSensitive(boolean flag) {
autoTextFieldEditor.getAutoTextFieldEditor().setCaseSensitive(flag);
}
public boolean isStrict() {
return autoTextFieldEditor.getAutoTextFieldEditor().isStrict();
}
public void setStrict(boolean flag) {
autoTextFieldEditor.getAutoTextFieldEditor().setStrict(flag);
}
public java.util.List<String> getDataList() {
return autoTextFieldEditor.getAutoTextFieldEditor().getDataList();
}
public void setDataList(java.util.List<String> list) {
autoTextFieldEditor.getAutoTextFieldEditor().setDataList(list);
setModel(new DefaultComboBoxModel(list.toArray()));
}
void setSelectedValue(Object obj) {
if (isFired) {
return;
} else {
isFired = true;
setSelectedItem(obj);
fireItemStateChanged(new ItemEvent(this, 701, selectedItemReminder, 1));
isFired = false;
return;
}
}
#Override
protected void fireActionEvent() {
if (!isFired) {
super.fireActionEvent();
}
}
}
AutoTextField
import java.util.List;
import javax.swing.JTextField;
import javax.swing.text.*;
public class Java2sAutoTextField extends JTextField {
private static final long serialVersionUID = 1L;
private List<String> dataList;
private boolean isCaseSensitive;
private boolean isStrict;
private Java2sAutoComboBox autoComboBox;
public class AutoDocument extends PlainDocument {
private static final long serialVersionUID = 1L;
#Override
public void replace(int i, int j, String s, AttributeSet attributeset)
throws BadLocationException {
super.remove(i, j);
insertString(i, s, attributeset);
}
#Override
public void insertString(int i, String s, AttributeSet attributeset)
throws BadLocationException {
if (s == null || "".equals(s)) {
return;
}
String s1 = getText(0, i);
String s2 = getMatch(s1 + s);
int j = (i + s.length()) - 1;
if (isStrict && s2 == null) {
s2 = getMatch(s1);
j--;
} else if (!isStrict && s2 == null) {
super.insertString(i, s, attributeset);
return;
}
if (autoComboBox != null && s2 != null) {
autoComboBox.setSelectedValue(s2);
}
super.remove(0, getLength());
super.insertString(0, s2, attributeset);
setSelectionStart(j + 1);
setSelectionEnd(getLength());
}
#Override
public void remove(int i, int j) throws BadLocationException {
int k = getSelectionStart();
if (k > 0) {
k--;
}
String s = getMatch(getText(0, k));
if (!isStrict && s == null) {
super.remove(i, j);
} else {
super.remove(0, getLength());
super.insertString(0, s, null);
}
if (autoComboBox != null && s != null) {
autoComboBox.setSelectedValue(s);
}
try {
setSelectionStart(k);
setSelectionEnd(getLength());
} catch (Exception exception) {
}
}
}
public Java2sAutoTextField(List<String> list) {
isCaseSensitive = false;
isStrict = true;
autoComboBox = null;
if (list == null) {
throw new IllegalArgumentException("values can not be null");
} else {
dataList = list;
init();
return;
}
}
Java2sAutoTextField(List<String> list, Java2sAutoComboBox b) {
isCaseSensitive = false;
isStrict = true;
autoComboBox = null;
if (list == null) {
throw new IllegalArgumentException("values can not be null");
} else {
dataList = list;
autoComboBox = b;
init();
return;
}
}
private void init() {
setDocument(new AutoDocument());
if (isStrict && dataList.size() > 0) {
setText(dataList.get(0).toString());
}
}
private String getMatch(String s) {
for (int i = 0; i < dataList.size(); i++) {
String s1 = dataList.get(i).toString();
if (s1 != null) {
if (!isCaseSensitive
&& s1.toLowerCase().startsWith(s.toLowerCase())) {
return s1;
}
if (isCaseSensitive && s1.startsWith(s)) {
return s1;
}
}
}
return null;
}
#Override
public void replaceSelection(String s) {
AutoDocument _lb = (AutoDocument) getDocument();
if (_lb != null) {
try {
int i = Math.min(getCaret().getDot(), getCaret().getMark());
int j = Math.max(getCaret().getDot(), getCaret().getMark());
_lb.replace(i, j - i, s, null);
} catch (Exception exception) {
}
}
}
public boolean isCaseSensitive() {
return isCaseSensitive;
}
public void setCaseSensitive(boolean flag) {
isCaseSensitive = flag;
}
public boolean isStrict() {
return isStrict;
}
public void setStrict(boolean flag) {
isStrict = flag;
}
public List<String> getDataList() {
return dataList;
}
public void setDataList(List<String> list) {
if (list == null) {
throw new IllegalArgumentException("values can not be null");
} else {
dataList = list;
return;
}
}
}
EDIT
output from Win7 64b / Java7
Metal L&F
Windows L&F (funny empty white space near Button in JComboBox)
Nimbus L&F
feel free for edit(s)

This component is called autocomplete and is included in a so called swing extensions porject.
Just have a look at: http://swingx.java.net/
There is a webstart: http://swinglabs-demos.java.net/demos/swingxset6/swingxset.jnlp
Autocomplete is the Menu to select. Have fun and less error prone code :)

obviously the glitch is in the textfield component used. What happens is, when windows look and feel is used , the text in this component is selected just as using the line "textfield.selectAll();", and hence when you type anything else the selected text is cleared form the textfield component. So in the below code the caret position of this component is adjusted. This is how it works, first store the current caret position of text field in a variable "currentCaretPosition", then move the caret position to the beginning in the text in the component. After filtering restoring the caret position back to the "currentCaretPosition" variable value. I hope it works as you want it to.
The refined code is given below:-
/****Beginning of code****/
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
public class FilterComboBox extends JComboBox {
private List<String> array;
private int currentCaretPosition=0;
public FilterComboBox(List<String> array) {
super(array.toArray());
this.array = array;
this.setEditable(true);
final JTextField textfield = (JTextField) this.getEditor().getEditorComponent();
textfield.addKeyListener(new KeyAdapter() {
public void keyPressed(KeyEvent ke) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
currentCaretPosition=textfield.getCaretPosition();
if(textfield.getSelectedText()==null)
{
textfield.setCaretPosition(0);
comboFilter(textfield.getText());
textfield.setCaretPosition(currentCaretPosition);
}
}
});
}
});
}
public void comboFilter(String enteredText) {
List<String> filterArray= new ArrayList<String>();
for (int i = 0; i < array.size(); i++) {
if (array.get(i).toLowerCase().contains(enteredText.toLowerCase())) {
filterArray.add(array.get(i));
}
}
if (filterArray.size() > 0) {
this.setModel(new DefaultComboBoxModel(filterArray.toArray()));
this.setSelectedItem(enteredText);
this.showPopup();
}
else {
this.hidePopup();
}
}
/* Testing Codes */
public static List<String> populateArray() {
List<String> test = new ArrayList<String>();
test.add("");
test.add("Mountain Flight");
test.add("Mount Climbing");
test.add("Trekking");
test.add("Rafting");
test.add("Jungle Safari");
test.add("Bungie Jumping");
test.add("Para Gliding");
return test;
}
public static void makeUI() {
JFrame frame = new JFrame("Adventure in Nepal - Combo Filter Test");
FilterComboBox acb = new FilterComboBox(populateArray());
frame.getContentPane().add(acb);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public static void main(String[] args) throws Exception {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
makeUI();
}
}
/******* End of code**********/

It looks like, as you mentioned, when user inputs any texts in combobox, the Windows Look & Feel selects (highlights) the entered text. So, when you press another key, it replaces the previous one. So, the solution is not to highlight the entered texts. You can achieve this by adding any one of the following statements in your keylistener.
textfield.setCaretPosition(textfield.getText().length());
OR
textfield.setSelectionStart(textfield.getText().length());
So, your keylistener should look like this :
final JTextField textfield = (JTextField) this.getEditor().getEditorComponent();
textfield.addKeyListener(new KeyAdapter() {
public void keyReleased(KeyEvent ke) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
comboFilter(textfield.getText());
textfield.setCaretPosition(textfield.getText().length());
}
});
}
});

how can i solve this error

This is the complete code :
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.lang.Thread;
class jProgressBar {
JProgressBar pb;
JButton start;
int i;
jProgressBar() {
buildGUI();
hookUpEvents();
}
public void buildGUI() {
JFrame fr=new JFrame("Progress Bar");
JPanel p=new JPanel();
p.setLayout(new FlowLayout(FlowLayout.CENTER));
JPanel barPanel=new JPanel();
barPanel.setLayout(new GridLayout(2,0,50,50));
pb=new JProgressBar(0,10);
start=new JButton("Start Demo");
fr.add(p);
barPanel.add(start);
barPanel.add(pb);
p.add(barPanel);
fr.setSize(500,500);
fr.setVisible(true);
}
public void hookUpEvents() {
start.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
try {
Runnable r=new Runnable() {
public void run() {
action(ae); // LINE 39
}
};
Thread th=new Thread(r);
th.start();
} catch(Exception exc) {
System.out.println(exc);
}
}
});
}
public void action(ActionEvent ae) {
start.setVisible(false);
try {
Runnable rp=new Runnable() {
public void run() {
i++;
pb.setValue(i);
try {
Thread.sleep(2000);
} catch(Exception exc) {
System.out.println(exc);
}
if(i==5) {
pb.setString("Half Done!");
}
else if(i==10) {
pb.setString("Completed!");
}
}
};
Thread th=new Thread(rp);
th.start();
} catch(Exception exc) {
System.out.println(exc);
}
}
public static void main(String args[]) {
new jProgressBar();
}
}
This is the error produced on cmd:
d:\UnderTest>javac jProgressBar.java
jProgressBar.java:39: local variable ae is accessed from within inner class; needs to be declared fina
l
action(ae);
^
1 error
What is this error and how can I solve this error?

Declare the variable ae as final:
public void actionPerformed(final ActionEvent ae) {
This means that it cannot be assigned a new value, which should be fine according to your current code.

a very nice example for SwingWorker
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
public class SwingWorkerExample extends JFrame implements ActionListener {
private static final long serialVersionUID = 1L;
private final JButton startButton, stopButton;
private JScrollPane scrollPane = new JScrollPane();
private JList listBox = null;
private DefaultListModel listModel = new DefaultListModel();
private final JProgressBar progressBar;
private mySwingWorker swingWorker;
public SwingWorkerExample() {
super("SwingWorkerExample");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
getContentPane().setLayout(new GridLayout(2, 2));
startButton = makeButton("Start");
stopButton = makeButton("Stop");
stopButton.setEnabled(false);
progressBar = makeProgressBar(0, 99);
listBox = new JList(listModel);
scrollPane.setViewportView(listBox);
getContentPane().add(scrollPane);
//Display the window.
pack();
setVisible(true);
}
//Class SwingWorker<T,V> T - the result type returned by this SwingWorker's doInBackground
//and get methods V - the type used for carrying out intermediate results by this SwingWorker's
//publish and process methods
private class mySwingWorker extends javax.swing.SwingWorker<ArrayList<Integer>, Integer> {
//The first template argument, in this case, ArrayList<Integer>, is what s returned by doInBackground(),
//and by get(). The second template argument, in this case, Integer, is what is published with the
//publish method. It is also the data type which is stored by the java.util.List that is the parameter
//for the process method, which recieves the information published by the publish method.
#Override
protected ArrayList<Integer> doInBackground() {
//Returns items of the type given as the first template argument to the SwingWorker class.
if (javax.swing.SwingUtilities.isEventDispatchThread()) {
System.out.println("javax.swing.SwingUtilities.isEventDispatchThread() returned true.");
}
Integer tmpValue = new Integer(1);
ArrayList<Integer> list = new ArrayList<Integer>();
for (int i = 0; i < 100; i++) {
for (int j = 0; j < 100; j++) { //find every 100th prime, just to make it slower
tmpValue = FindNextPrime(tmpValue.intValue());
//isCancelled() returns true if the cancel() method is invoked on this class. That is the proper way
//to stop this thread. See the actionPerformed method.
if (isCancelled()) {
System.out.println("SwingWorker - isCancelled");
return list;
}
}
//Successive calls to publish are coalesced into a java.util.List, which is what is received by process,
//which in this case, isused to update the JProgressBar. Thus, the values passed to publish range from
//1 to 100.
publish(new Integer(i));
list.add(tmpValue);
}
return list;
}//Note, always use java.util.List here, or it will use the wrong list.
#Override
protected void process(java.util.List<Integer> progressList) {
//This method is processing a java.util.List of items given as successive arguments to the publish method.
//Note that these calls are coalesced into a java.util.List. This list holds items of the type given as the
//second template parameter type to SwingWorker. Note that the get method below has nothing to do with the
//SwingWorker get method; it is the List's get method. This would be a good place to update a progress bar.
if (!javax.swing.SwingUtilities.isEventDispatchThread()) {
System.out.println("javax.swing.SwingUtilities.isEventDispatchThread() + returned false.");
}
Integer percentComplete = progressList.get(progressList.size() - 1);
progressBar.setValue(percentComplete.intValue());
}
#Override
protected void done() {
System.out.println("doInBackground is complete");
if (!javax.swing.SwingUtilities.isEventDispatchThread()) {
System.out.println("javax.swing.SwingUtilities.isEventDispatchThread() + returned false.");
}
try {
//Here, the SwingWorker's get method returns an item of the same type as specified as the first type parameter
//given to the SwingWorker class.
ArrayList<Integer> results = get();
for (Integer i : results) {
listModel.addElement(i.toString());
}
} catch (Exception e) {
System.out.println("Caught an exception: " + e);
}
startButton();
}
boolean IsPrime(int num) { //Checks whether a number is prime
int i;
for (i = 2; i <= num / 2; i++) {
if (num % i == 0) {
return false;
}
}
return true;
}
protected Integer FindNextPrime(int num) { //Returns next prime number from passed arg.
do {
if (num % 2 == 0) {
num++;
} else {
num += 2;
}
} while (!IsPrime(num));
return new Integer(num);
}
}
private JButton makeButton(String caption) {
JButton b = new JButton(caption);
b.setActionCommand(caption);
b.addActionListener(this);
getContentPane().add(b);
return b;
}
private JProgressBar makeProgressBar(int min, int max) {
JProgressBar progressBar1 = new JProgressBar();
progressBar1.setMinimum(min);
progressBar1.setMaximum(max);
progressBar1.setStringPainted(true);
progressBar1.setBorderPainted(true);
getContentPane().add(progressBar1);
return progressBar1;
}
private void startButton() {
startButton.setEnabled(true);
stopButton.setEnabled(false);
System.out.println("SwingWorker - Done");
}
#Override
public void actionPerformed(ActionEvent e) {
if ("Start" == null ? e.getActionCommand() == null : "Start".equals(e.getActionCommand())) {
startButton.setEnabled(false);
stopButton.setEnabled(true);
// Note that it creates a new instance of the SwingWorker-derived class. Never reuse an old one.
(swingWorker = new mySwingWorker()).execute(); // new instance
} else if ("Stop" == null ? e.getActionCommand() == null : "Stop".equals(e.getActionCommand())) {
startButton.setEnabled(true);
stopButton.setEnabled(false);
swingWorker.cancel(true); // causes isCancelled to return true in doInBackground
swingWorker = null;
}
}
public static void main(String[] args) {
// Notice that it kicks it off on the event-dispatching thread, not the main thread.
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
SwingWorkerExample swingWorkerExample = new SwingWorkerExample();
}
});
}
}

There are some counterproductive issues present.
Swing is single-thread based, and all actions must be done on the EDT. For that reason, your JProgressBar doesn't update correctly. See also Concurrency in Swing.
Don't use Thread.sleep(int) in Swing, and certainly not in an action listener.
By using Runnable, it is possible to update JProgressBar; but as mentioned, the method must be run from invokeLater().
For that, SwingWorker would be better, as shown below and here.
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.*;
public class TestProgressBar {
private static void createAndShowUI() {
JFrame frame = new JFrame("TestProgressBar");
frame.getContentPane().add(new TestPBGui().getMainPanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowUI();
}
});
}
private TestProgressBar() {
}
}
class TestPBGui {
private JPanel mainPanel = new JPanel();
public TestPBGui() {
JButton yourAttempt = new JButton("Your attempt to show Progress Bar");
JButton myAttempt = new JButton("My attempt to show Progress Bar");
yourAttempt.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
yourAttemptActionPerformed();
}
});
myAttempt.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
myAttemptActionPerformed();
}
});
mainPanel.add(yourAttempt);
mainPanel.add(myAttempt);
}
private void yourAttemptActionPerformed() {
Window thisWin = SwingUtilities.getWindowAncestor(mainPanel);
JDialog progressDialog = new JDialog(thisWin, "Uploading...");
JPanel contentPane = new JPanel();
contentPane.setPreferredSize(new Dimension(300, 100));
JProgressBar bar = new JProgressBar(0, 100);
bar.setIndeterminate(true);
contentPane.add(bar);
progressDialog.setContentPane(contentPane);
progressDialog.pack();
progressDialog.setLocationRelativeTo(null);
Task task = new Task("Your attempt");
task.execute();
progressDialog.setVisible(true);
while (!task.isDone()) {
}
progressDialog.dispose();
}
private void myAttemptActionPerformed() {
Window thisWin = SwingUtilities.getWindowAncestor(mainPanel);
final JDialog progressDialog = new JDialog(thisWin, "Uploading...");
JPanel contentPane = new JPanel();
contentPane.setPreferredSize(new Dimension(300, 100));
final JProgressBar bar = new JProgressBar(0, 100);
bar.setIndeterminate(true);
contentPane.add(bar);
progressDialog.setContentPane(contentPane);
progressDialog.pack();
progressDialog.setLocationRelativeTo(null);
final Task task = new Task("My attempt");
task.addPropertyChangeListener(new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if (evt.getPropertyName().equalsIgnoreCase("progress")) {
int progress = task.getProgress();
if (progress == 0) {
bar.setIndeterminate(true);
} else {
bar.setIndeterminate(false);
bar.setValue(progress);
progressDialog.dispose();
}
}
}
});
task.execute();
progressDialog.setVisible(true);
}
public JPanel getMainPanel() {
return mainPanel;
}
}
class Task extends SwingWorker<Void, Void> {
private static final long SLEEP_TIME = 4000;
private String text;
public Task(String text) {
this.text = text;
}
#Override
public Void doInBackground() {
setProgress(0);
try {
Thread.sleep(SLEEP_TIME);// imitate a long-running task
} catch (InterruptedException e) {
}
setProgress(100);
return null;
}
#Override
public void done() {
System.out.println(text + " is done");
Toolkit.getDefaultToolkit().beep();
}
}