I am having two classes, a main class and class which extends JPanel and implements Runnable. I am trying to create two threads for the same instance of the JPanel class in an actionListener, but i just don't know where to create the JPanel1 object...
//Edit: Button1 is the start of the application .After that , button 2 will appear with a quick animation of labels and when clicked it(button2) will start the same animation too. How can i do whenever one of these buttons is clicked to launch the run method ?
public void run() {
if(isTom){
repaint();
revalidate();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
}
panel.removeAll();
panel.add(tomLabel1);
repaint();
revalidate();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
}
panel.add(tomLabel2);
repaint();
revalidate();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
}
panel.add(tomLabel3);
repaint();
revalidate();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
}
panel.add(tomLabel4);
repaint();
revalidate();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
}
panel.add(tomLabel5);
repaint();
revalidate();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
}
panel.removeAll();
repaint();
revalidate();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
}
}
public Game(){
JFrame frame = new JFrame();
Panel1 key = new Panel1();
key.addKeyListener(key);
frame.add(key);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setUndecorated(true);
frame.setVisible(true);
}
public static void main(String[] args) {
new Game();
}
public class Panel1 extends JPanel implements KeyListener,Runnable{
JButton button1 = new JButton("BUTTON1");
JButton button2 = new JButton("BUTTON2");
add(button1);add(button2);
Thread t = new Thread(this); // This works, but i need it inside the actionListener.
button1.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
System.out.println("button1");
Thread x = new Thread(j);//'j' is an JPanel1 object. I need something like this i guess
x.setName("Thread x");});
button2.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
System.out.println("button2");
Thread y = new Thread(j);
y.setName("Thread y");
});
public void run(){
System.out.println(Thread.currentThread().getName());
}
First, Swing is NOT thread safe! This means that you should NEVER create or modify the UI from outside of context of the Event Dispatching Thread!
Second, Swing is a single threaded environment, this means that you should never block or execute long running code from within the context of the Event Dispatching Thread, this will cause the UI to freeze until the block is removed.
Your concept is correct, you implementation is wrong, you should use a Swing Timer instead.
Instead of removing and adding labels, use a single label and change it's properties (text/icon, what ever)
See Concurrency in Swing and How to use Swing Timers for more details
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.HeadlessException;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
try {
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (IOException exp) {
exp.printStackTrace();
}
}
});
}
public class TestPane extends JPanel {
private JButton button1;
private JButton button2;
private SplashScreen splashScreen;
public TestPane() throws IOException {
button1 = new JButton("Button One");
button2 = new JButton("Button Two");
JPanel buttons = new JPanel();
buttons.add(button1);
buttons.add(button2);
button1.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
splashScreen.run();
}
});
button2.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
splashScreen.run();
}
});
splashScreen = new SplashScreen();
setLayout(new BorderLayout());
add(splashScreen);
add(buttons, BorderLayout.SOUTH);
}
}
public static class SplashScreen extends JPanel {
protected static final int IMAGE_COUNT = 4;
private JLabel label;
private Timer timer;
private int delta;
private int count;
private Icon[] icons;
private Dimension preferredSize;
public SplashScreen() throws IOException {
String path = "/images/splash";
String ext = ".png";
icons = new Icon[IMAGE_COUNT];
int maxWidth = 0;
int maxHeight = 0;
for (int index = 0; index < IMAGE_COUNT; index++) {
String name = path + (index + 1) + ext;
System.out.println(name);
icons[index] = new ImageIcon(ImageIO.read(getClass().getResource(name)));
maxWidth = Math.max(maxWidth, icons[index].getIconWidth());
maxHeight = Math.max(maxHeight, icons[index].getIconHeight());
}
preferredSize = new Dimension(maxWidth, maxHeight);
timer = new Timer(250, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (count >= IMAGE_COUNT) {
count = IMAGE_COUNT - 2;
delta = -1;
} else if (count < 0) {
((Timer)e.getSource()).stop();
} else {
label.setIcon(icons[count]);
count += delta;
}
}
});
setLayout(new BorderLayout());
label = new JLabel();
add(label);
}
#Override
public Dimension getPreferredSize() {
return preferredSize;
}
public void run() {
if (!timer.isRunning()) {
delta = 1;
count = 0;
timer.start();
}
}
}
}
Create a new instance of a Thread with your Panel1 class instance:
button1.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
System.out.println("button1");
Thread x = new Thread(Panel1.this);
x.start();
x.setName("Thread x");});
Repeat for the other button with a new Thread object:
button2.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
System.out.println("button2");
Thread y = new Thread(Panel1.this);
y.start();
y.setName("Thread y"); });
Panel1.this is referring to the instance of the Panel1 class that is currently running, making sure that your Threads are executing run() of that instance.
Related
I am creating a Java Swing game and before every new game I would like to have a frame show up and countdown from 5 to 0 seconds.
While this is happening I would like the game in the background to wait until the countdown is complete. What would be the best way to make the game in the background wait?
I have tried Thread.sleep but this causes the The Event Dispatch Thread to sleep and the GUI not to update. However, it works the first time i run it but not the second.
Thankful for your help.
public class CountdownPresenterPanel {
JFrame mainFrame;
int currentNumber = 5;
JLabel textLabel;
CountdownPresenterPanel() {
mainFrame = new JFrame();
textLabel = new JLabel(String.valueOf(currentNumber), SwingConstants.CENTER);
textLabel.setFont(new Font("Arial", Font.BOLD, 55));
textLabel.setVerticalAlignment(SwingConstants.CENTER);
mainFrame.add(textLabel);
mainFrame.setUndecorated(true); // Remove bar including close, minimize
mainFrame.setSize(600,300);
mainFrame.setLocationRelativeTo(null);
mainFrame.setVisible(true);
Timer timer = new Timer(1000, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if(currentNumber > 0) {
currentNumber--;
textLabel.setText(String.valueOf(currentNumber));
} else {
mainFrame.setVisible(false);
mainFrame.dispose();
}
}
});
timer.setRepeats(true);
timer.start();
}
}
Solution
import java.awt.*;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JDialog;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import javax.swing.Timer;
public class CountdownPresenterPanel {
private int currentNumber = 5;
private JLabel textLabel;
private final JDialog dialog;
CountdownPresenterPanel() {
Timer timer = new Timer(1000, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if(currentNumber > 0) {
currentNumber--;
textLabel.setText(String.valueOf(currentNumber));
} else {
dialog.dispose();
}
}
});
Frame window = new Frame();
dialog = new JDialog(window, "Alert", true);
textLabel = new JLabel(String.valueOf(currentNumber), SwingConstants.CENTER);
textLabel.setFont(new Font("Arial", Font.BOLD, 55)); // Increase the font-size
dialog.add(textLabel);
dialog.setSize(400, 200);
dialog.setLocationRelativeTo(null);
timer.setRepeats(true);
timer.start();
dialog.setUndecorated(true);
dialog.setVisible(true);
}
}
Don't use a JFrame, use some kind of modal dialog
Take a look at How to Make Dialogs for more details
Seems that you want something like a SplashScreen. Have you looked to the SplasScreen Tutorial from Oracle? There Thread.sleep() is used safely and it updates the graphics correctly. I think it to be your unique solution. The only way to let the undergoing application to wait is to use the same thread. The reason your Timer didn't work is because it creates another thread to run itself.
Another option is to use a SwingWorker:
import java.awt.*;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.beans.*;
import javax.swing.*;
public class CountdownPresenterPanel2 {
public static void main(String[] args) {
final JFrame frame = new JFrame();
final JDialog splashScreen = new JDialog(null, Dialog.ModalityType.DOCUMENT_MODAL);
final JLabel textLabel = new JLabel(String.valueOf(5), SwingConstants.CENTER);
EventQueue.invokeLater(new Runnable() {
#Override public void run() {
textLabel.setFont(new Font("Arial", Font.BOLD, 55));
textLabel.setVerticalAlignment(SwingConstants.CENTER);
splashScreen.setUndecorated(true);
splashScreen.getContentPane().add(textLabel);
splashScreen.setSize(600, 300);
splashScreen.setLocationRelativeTo(null);
splashScreen.setVisible(true);
}
});
(new GamePanelInitTask() {
#Override protected void process(java.util.List<Integer> chunks) {
for (Integer value : chunks) {
textLabel.setText(value.toString());
}
}
#Override public void done() {
splashScreen.dispose();
try {
MainGamePanel p = get();
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.getContentPane().add(p);
frame.setSize(320, 240);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
} catch (InterruptedException | ExecutionException ex) {
ex.printStackTrace();
}
}
}).execute();
}
}
class GamePanelInitTask extends SwingWorker<MainGamePanel, Integer> {
#Override public MainGamePanel doInBackground() {
int currentNumber = 5;
MainGamePanel game = new MainGamePanel();
while (currentNumber > 0 && !isCancelled()) {
currentNumber--;
publish(currentNumber);
game.add(new JLabel(String.format("Label: %d", currentNumber)));
try {
Thread.sleep(1000); //dummy task
} catch (InterruptedException ie) {
ie.printStackTrace();
return null;
}
}
return game;
}
}
class MainGamePanel extends JPanel {
public MainGamePanel() {
super();
try {
Thread.sleep(1000); //dummy task
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
I am building a java app and I want to change the theme(look and feel) of application at runtime with these radio buttons. I do not know how to do this!
Thanks in advance!
You can do that by calling SwingUtilities.updateTreeComponentUI(frame) and passing container component. Be aware that it won't be efficient always. So something like this:
public static void changeLaf(JFrame frame) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException
| IllegalAccessException | UnsupportedLookAndFeelException e) {
e.printStackTrace();
}
SwingUtilities.updateComponentTreeUI(frame);
}
This method changes current LaF to systems.
EDIT:
Changing LaF via JRadioMenuItem demo:
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JPanel;
import javax.swing.JRadioButtonMenuItem;
import javax.swing.JScrollPane;
import javax.swing.JSpinner;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;
public class LafDemo {
public static void changeLaf(JFrame frame, String laf) {
if (laf.equals("metal")) {
try {
UIManager.setLookAndFeel(UIManager
.getCrossPlatformLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException
| IllegalAccessException | UnsupportedLookAndFeelException e) {
e.printStackTrace();
}
}
if (laf.equals("nimbus")) {
try {
UIManager
.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
} catch (ClassNotFoundException | InstantiationException
| IllegalAccessException | UnsupportedLookAndFeelException e) {
e.printStackTrace();
}
}
if (laf.equals("system")) {
try {
UIManager.setLookAndFeel(UIManager
.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException
| IllegalAccessException | UnsupportedLookAndFeelException e) {
e.printStackTrace();
}
}
SwingUtilities.updateComponentTreeUI(frame);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
final JFrame frame = new JFrame();
JPanel panel = new JPanel();
JButton btnDemo = new JButton("JButton");
JSpinner spnDemo = new JSpinner();
JComboBox<String> cmbDemo = new JComboBox<String>();
cmbDemo.addItem("One");
cmbDemo.addItem("Two");
cmbDemo.addItem("Three");
JMenuBar mBar = new JMenuBar();
frame.setJMenuBar(mBar);
JMenu mnuLaf = new JMenu("Look and feel");
JRadioButtonMenuItem mniNimbus = new JRadioButtonMenuItem(
"Nimbus");
JRadioButtonMenuItem mniMetal = new JRadioButtonMenuItem(
"Metal");
JRadioButtonMenuItem mniSystem = new JRadioButtonMenuItem(
"Systems");
ButtonGroup btnGroup = new ButtonGroup();
btnGroup.add(mniNimbus);
btnGroup.add(mniMetal);
btnGroup.add(mniSystem);
mBar.add(mnuLaf);
mnuLaf.add(mniNimbus);
mnuLaf.add(mniMetal);
mnuLaf.add(mniSystem);
mniNimbus.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
changeLaf(frame, "nimbus");
}
});
mniMetal.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
changeLaf(frame, "metal");
}
});
mniSystem.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
changeLaf(frame, "system");
}
});
DefaultTableModel model = new DefaultTableModel(
new Object[][] {}, new String[] { "First", "Second" });
model.addRow(new Object[] { "Some text", "Another text" });
JTable table = new JTable(model);
panel.add(btnDemo);
panel.add(spnDemo);
panel.add(cmbDemo);
frame.add(panel, BorderLayout.NORTH);
frame.add(new JScrollPane(table), BorderLayout.CENTER);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
});
}
}
You simply need to use the UIManager.LookAndFeelInfo[] to store the available LookAndFeel, then use UIManager.setLookAndFeel(LookAndFeelClassName) to set and after this do call SwingUtilities.updateComponentTreeUI(frameReference)
EDIT :
Do call pack on JFrame/JWindow/JDialog(parent container) at the end, as very much specified by the Swing Lord #AndrewThompson.
Please have a look at this small example :
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class LookAndFeelDemo {
private JFrame frame;
private JButton button;
private int counter;
private Timer timer;
private JLabel lafNameLabel;
private UIManager.LookAndFeelInfo[] lafs;
public LookAndFeelDemo() {
lafs = UIManager.getInstalledLookAndFeels();
counter = 0;
}
private ActionListener eventActions = new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
if (ae.getSource() == timer) {
counter %= lafs.length;
try {
UIManager.setLookAndFeel(lafs[counter].getClassName());
} catch(Exception e) {e.printStackTrace();}
SwingUtilities.updateComponentTreeUI(frame);
lafNameLabel.setText(lafs[counter++].getName());
frame.pack();
} else if (ae.getSource() == button) {
if (timer.isRunning()) {
timer.stop();
button.setText("Start");
} else {
timer.start();
button.setText("Stop");
}
}
}
};
private void displayGUI() {
frame = new JFrame("Swing Worker Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel contentPane = new JPanel();
lafNameLabel = new JLabel("Nothing to display yet...", JLabel.CENTER);
button = new JButton("Stop");
button.addActionListener(eventActions);
contentPane.add(lafNameLabel);
contentPane.add(button);
frame.addWindowListener(new WindowAdapter() {
#Override
public void windowClosed(WindowEvent e) {
timer.stop();
}
});
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
timer = new Timer(1000, eventActions);
timer.start();
}
public static void main(String[] args) {
Runnable runnable = new Runnable() {
#Override
public void run() {
new LookAndFeelDemo().displayGUI();
}
};
EventQueue.invokeLater(runnable);
}
}
EDIT 2 :
Updating the code example to include adding LookAndFeels from JRadioButtonMenuItem on the fly. Though please, be advised, it would be much better if you use Action instead of an ActionListener, I used it only to incorporate the changes in the previous code :-)
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class LookAndFeelDemo {
private JFrame frame;
private JButton button;
private int counter;
private Timer timer;
private JLabel lafNameLabel;
private ButtonGroup bg;
private JRadioButtonMenuItem[] radioItems;
private UIManager.LookAndFeelInfo[] lafs;
public LookAndFeelDemo() {
lafs = UIManager.getInstalledLookAndFeels();
counter = 0;
}
private ActionListener eventActions = new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
if (ae.getSource() == timer) {
counter %= lafs.length;
try {
UIManager.setLookAndFeel(lafs[counter].getClassName());
} catch(Exception e) {e.printStackTrace();}
SwingUtilities.updateComponentTreeUI(frame);
lafNameLabel.setText(lafs[counter++].getName());
frame.pack();
} else if (ae.getSource() == button) {
if (timer.isRunning()) {
timer.stop();
button.setText("Start");
} else {
timer.start();
button.setText("Stop");
}
} else if (ae.getSource() instanceof JRadioButtonMenuItem) {
JRadioButtonMenuItem radioItem = (JRadioButtonMenuItem) ae.getSource();
String lafName = radioItem.getActionCommand();
System.out.println("LAF Name : " + lafName);
for (int i = 0; i < radioItems.length; i++) {
if (lafName.equals(radioItems[i].getActionCommand())) {
setApplicationLookAndFeel(lafs[i].getClassName());
}
}
}
}
private void setApplicationLookAndFeel(String className) {
try {
UIManager.setLookAndFeel(className);
} catch (Exception e) {e.printStackTrace();}
SwingUtilities.updateComponentTreeUI(frame);
frame.pack();
}
};
private void displayGUI() {
frame = new JFrame("Swing Worker Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel contentPane = new JPanel();
lafNameLabel = new JLabel("Nothing to display yet...", JLabel.CENTER);
button = new JButton("Start");
button.addActionListener(eventActions);
contentPane.add(lafNameLabel);
contentPane.add(button);
frame.addWindowListener(new WindowAdapter() {
#Override
public void windowClosed(WindowEvent e) {
timer.stop();
}
});
frame.setJMenuBar(getMenuBar());
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
timer = new Timer(1000, eventActions);
}
private JMenuBar getMenuBar() {
JMenuBar menuBar = new JMenuBar();
JMenu lookAndFeelMenu = new JMenu("Look And Feels");
bg = new ButtonGroup();
radioItems = new JRadioButtonMenuItem[lafs.length];
for (int i = 0; i < radioItems.length; i++) {
radioItems[i] = new JRadioButtonMenuItem(lafs[i].getName());
radioItems[i].addActionListener(eventActions);
bg.add(radioItems[i]);
lookAndFeelMenu.add(radioItems[i]);
}
menuBar.add(lookAndFeelMenu);
return menuBar;
}
public static void main(String[] args) {
Runnable runnable = new Runnable() {
#Override
public void run() {
new LookAndFeelDemo().displayGUI();
}
};
EventQueue.invokeLater(runnable);
}
}
Well, considering Nimbus is currently selected, I am going to assume that you want to change the LAF to Nimbus? If so, you will need to do this:
UIManager.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
If you want to see all of the LAFs that are currently installed, you could use UIManager.getInstalledLookAndFeels();. For more information, consider reading this
Here's mine:
You should call this method when a Action event occurs when the user clicks on a JMenuItem or something else of your choice.
private void changeLookAndFeel() {
final LookAndFeelInfo[] list = UIManager.getInstalledLookAndFeels();
final List<String> lookAndFeelsDisplay = new ArrayList<>();
final List<String> lookAndFeelsRealNames = new ArrayList<>();
for (LookAndFeelInfo each : list) {
lookAndFeelsDisplay.add(each.getName());
lookAndFeelsRealNames.add(each.getClassName());
}
if (lookAndFeelsDisplay.size() != lookAndFeelsRealNames.size()) {
throw new InternalError();
}
String changeSpeed = (String) JOptionPane.showInputDialog(this, "Choose Look and Feel Here\n(these are all available on your system):", "Choose Look And Feel", JOptionPane.QUESTION_MESSAGE, null, lookAndFeelsDisplay.toArray(), null);
boolean update = false;
if (changeSpeed != null && changeSpeed.length() > 0) {
for (int a = 0; a < lookAndFeelsDisplay.size(); a++) {
if (changeSpeed.equals(lookAndFeelsDisplay.get(a))) {
try {
UIManager.setLookAndFeel(lookAndFeelsRealNames.get(a)); //re update with correct class name String
this.whichLookAndFeel = changeSpeed;
update = true;
}
catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
err.println(ex);
ex.printStackTrace();
Logger.getLogger(Starfighter.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
if (update) {
int width = 800;
int height = 625;
if (UIManager.getLookAndFeel().getName().equals("CDE/Motif")) {
height += 12;
}
this.setSize(width, height);
this.menuBar.updateUI();
this.menuBar = new JMenuBar();
menuBar.updateUI();
this.setJMenuBar(menuBar);
}
}
I have two Java(.java) files. One has a JButton and JTextField and the other has a Thread. In first Java file, I have added an ActionListener to the JButton so that, when the button is pressed, a thread (object for 2nd .java file in created and thread is initiated) runs which modifies an integer variable continuously. How to display the value of that integer variable (of 2nd .java file) in the JTextField (of 1st .java file) ?
Detection.java
package sample;
public class Detection implements Runnable
{
public String viewers;
public int count;
public void run()
{
try
{
while (true)
{
// i have written code for displaying video.
// and it say how many no. of people in the video
// the no of people is stored in a variable "count"
viewers=""+count; //storing count as string so as to display in the JTextField
}
}
catch (Exception e)
{
System.out.println("Exception: "+e);
}
}
}
UsrInterfac.java
//build using WindowBuilder eclipse juno
package sample;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JTextField;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class UsrInterfac
{
private JFrame frame;
private JTextField textField;
Detection dd = new Detection();
Thread th = new Thread(dd);
/**
* Launch the application.
*/
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
try
{
UsrInterfac window = new UsrInterfac();
window.frame.setVisible(true);
}
catch (Exception e)
{
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public UsrInterfac()
{
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize()
{
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JButton btnStartThread = new JButton("Start Thread");
btnStartThread.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
th.start();
}
});
btnStartThread.setBounds(59, 133, 117, 23);
frame.getContentPane().add(btnStartThread);
textField = new JTextField();
textField.setBounds(270, 134, 104, 20);
frame.getContentPane().add(textField);
textField.setColumns(10);
}
}
Starting from the basics, while using Swing, it is always best to use LayoutManagers, which can make your work much more easier, in comparison to using Absolute Positioning.
Whenever one needs to change something in the View from some another thread, it is always advisable to do that using EventQueue.invokeLater(...)/EventQueue.invokeAndWait(...).
This small sample program, might be able to help you get an idea, how to accomplish what you so desire :-)
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ThreadCounter
{
private CustomThread cThread;
private JTextField tField;
private JButton button;
private int counter;
public ThreadCounter()
{
counter = 0;
}
private void displayGUI()
{
JFrame frame = new JFrame("Thread Counter Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel contentPane = new JPanel();
tField = new JTextField(10);
tField.setText("0");
button = new JButton("Start");
button.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent ae)
{
if (counter == 0)
{
cThread = new CustomThread(tField);
cThread.setFlagValue(true);
cThread.start();
counter = 1;
button.setText("Stop");
}
else
{
try
{
cThread.setFlagValue(false);
cThread.join();
}
catch(InterruptedException ie)
{
ie.printStackTrace();
}
counter = 0;
button.setText("Start");
}
}
});
contentPane.add(tField);
contentPane.add(button);
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
#Override
public void run()
{
new ThreadCounter().displayGUI();
}
});
}
}
class CustomThread extends Thread
{
private int changingVariable;
private JTextField tField;
private boolean flag = true;
public CustomThread(JTextField tf)
{
changingVariable = 0;
tField = tf;
}
public void setFlagValue(boolean flag)
{
this.flag = flag;
}
#Override
public void run()
{
while (flag)
{
EventQueue.invokeLater(new Runnable()
{
#Override
public void run()
{
tField.setText(
Integer.toString(
++changingVariable));
}
});
try
{
Thread.sleep(1000);
}
catch(InterruptedException ie)
{
ie.printStackTrace();
}
}
System.out.println("I am OUT of WHILE");
}
}
Ideally you should post your code. Anyway, when you are calling the thread code, either pass the instance of the first class (object) or an instance of JTextField, so that the thread can set the new value in the text field.
f.e. I have an email client, it receives new message, button with incoming messages starts doing something, until user clicks it to see whats up.
I'm trying to make button attract attention by selecting, waiting and then deselecting it, but this does nothing!
do{
button.setSelected(true);
Thread oThread = new Thread() {
#Override
public void run() {
synchronized (this) {
try {
wait(1000);
} catch (InterruptedException e1) {
e1.printStackTrace();
}
}
button.setSelected(false);
}
};
oThread.start();
}while(true);
You should use Swing timers for that. Don't interact with GUI objects from foreign threads.
There's some docs in the Java tutorial: How to use Swing timers.
Here's an example way you could do this playing with the button's icon.
// member var
Icon buttonIcon;
Timer timer;
// in constructor for example
buttonIcon = new ImageIcon("resources/icon.png");
button.setIcon(buttonIcon);
timer = new Timer(1000, this);
timer.start();
// in the actionPerformed handler
if (button.getIcon() == null)
button.setIcon(icon);
else
button.setIcon(null);
Your class will need to implement ActionListener for this to work like that. Add some logic to stop the flashing when you need it.
hafl_workaround to your questions
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ShakingButtonDemo implements Runnable {
private JButton button;
private JRadioButton radioWholeButton;
private JRadioButton radioTextOnly;
public static void main(String[] args) throws Exception {
SwingUtilities.invokeLater(new ShakingButtonDemo());
}
#Override
public void run() {
radioWholeButton = new JRadioButton("The whole button");
radioTextOnly = new JRadioButton("Button text only");
radioWholeButton.setSelected(true);
ButtonGroup bg = new ButtonGroup();
bg.add(radioWholeButton);
bg.add(radioTextOnly);
button = new JButton(" Shake with this Button ");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
shakeButton(radioWholeButton.isSelected());
}
});
JPanel p1 = new JPanel();
p1.setBorder(BorderFactory.createTitledBorder("Shake Options"));
p1.setLayout(new GridLayout(0, 1));
p1.add(radioWholeButton);
p1.add(radioTextOnly);
JPanel p2 = new JPanel();
p2.setLayout(new GridLayout(0, 1));
p2.add(button);
JFrame frame = new JFrame();
frame.setTitle("Shaking Button Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(p1, BorderLayout.NORTH);
frame.add(p2, BorderLayout.SOUTH);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private void shakeButton(final boolean shakeWholeButton) {
final Point point = button.getLocation();
final Insets margin = button.getMargin();
final int delay = 75;
Runnable r = new Runnable() {
#Override
public void run() {
for (int i = 0; i < 30; i++) {
try {
if (shakeWholeButton) {
moveButton(new Point(point.x + 5, point.y));
Thread.sleep(delay);
moveButton(point);
Thread.sleep(delay);
moveButton(new Point(point.x - 5, point.y));
Thread.sleep(delay);
moveButton(point);
Thread.sleep(delay);
} else {// text only
setButtonMargin(new Insets(margin.top, margin.left + 3, margin.bottom, margin.right - 2));
Thread.sleep(delay);
setButtonMargin(margin);
Thread.sleep(delay);
setButtonMargin(new Insets(margin.top, margin.left - 2, margin.bottom, margin.right + 3));
Thread.sleep(delay);
setButtonMargin(margin);
Thread.sleep(delay);
}
} catch (InterruptedException ex) {
ex.printStackTrace();
}
}
}
};
Thread t = new Thread(r);
t.start();
}
private void moveButton(final Point p) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
button.setLocation(p);
}
});
}
private void setButtonMargin(final Insets margin) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
button.setMargin(margin);
}
});
}
}
I'm trying to get a SwingWorker to work.
I've the following code at the moment:
public class ImageWorker extends SwingWorker<Void, Void> implements KeyListener
{
private JLabel imageLabel;
private ImageIcon basicImage;
private ImageIcon whiteImage;
public static void main(String[] args)
{
new ImageWorker();
}
public ImageWorker()
{
final JFrame frame = new JFrame();
imageLabel = new JLabel();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 400);
frame.getContentPane().add(imageLabel);
frame.setVisible(true);
try
{
basicImage = new ImageIcon(ImageIO.read(new File("src\\img\\basis1.jpg")).getScaledInstance(1024, 768, Image.SCALE_SMOOTH));
whiteImage = new ImageIcon(ImageIO.read(new File("src\\img\\wit.jpg")).getScaledInstance(1024, 768, Image.SCALE_SMOOTH));
}
catch(IOException ex)
{
ex.getMessage();
}
this.execute();
}
#Override
protected Void doInBackground()
{
try
{
while (true)
{
displayImage(basicImage);
Thread.sleep(1000L);
if(isCancelled())
return null;
}
}
catch(InterruptedException e)
{
e.getMessage();
}
return null;
}
private void displayImage(final Icon image)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
imageLabel.setIcon(image);
}
});
}
I was expecting the images to appear in the JLabel, but I only see the JFrame popping up. The files are loaded correctly Ive tested that in another setup.
Any pointers?
Here is an example using a Timer rather than using the SwingWorker which really isn't appropriate to your situation. Note that it's not too different from your existing code.
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.Timer;
public class ImageWorker implements KeyListener
{
private JLabel imageLabel;
private ImageIcon basicImage;
private ImageIcon whiteImage;
private boolean isBasic = true;
private int delay = 1000; //milliseconds
private Timer timer;
public static void main(String[] args)
{
new ImageWorker();
}
public ImageWorker()
{
final JFrame frame = new JFrame();
imageLabel = new JLabel();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400, 400);
frame.getContentPane().add(imageLabel);
frame.setVisible(true);
try
{
basicImage = new ImageIcon(ImageIO.read(new File("src\\img\\basis1.jpg")).getScaledInstance(1024, 768, Image.SCALE_SMOOTH));
whiteImage = new ImageIcon(ImageIO.read(new File("src\\img\\wit.jpg")).getScaledInstance(1024, 768, Image.SCALE_SMOOTH));
}
catch (IOException ex)
{
ex.getMessage();
ex.printStackTrace();
}
frame.addKeyListener(this);
ActionListener taskPerformer = new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if(isBasic) {
//display basic image
imageLabel.setIcon(basicImage);
}
else {
//display white image
imageLabel.setIcon(whiteImage);
}
//toggle the flag
isBasic = !isBasic;
}
};
//use a timer instead of SwingWorker
timer = new Timer(delay, taskPerformer);
timer.start();
}
#Override
public void keyPressed(KeyEvent e)
{
//key pressed, we want to stop toggling so stop the timer
timer.stop();
//do whatever else you were doing to set the value for isCancelled();
}
#Override
public void keyReleased(KeyEvent e)
{
// TODO Auto-generated method stub
}
#Override
public void keyTyped(KeyEvent e)
{
// TODO Auto-generated method stub
}
}
A SwingWorker is not appropriate for your situation look into a Timer in the swing package. Here is a link to the API: http://download.oracle.com/javase/6/docs/api/javax/swing/Timer.html
You have the timer run and change an image every second since that is what you need.
Also, whenever you have exceptions, print out a stacktrace or the message at least. Otherwise you won't know if an exception occurs and is caught.