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How do I implement the codes which works as a timer app using awt,swing,Thread while satisfying some conditions?

I have to make the timer codes of Java using awt,swing,Thread.
The overview of the eventual app has below 4 features.
The app has just one button.
Firstly the button display the "START"on the button itself.
Dynamic time is displayed on the button as the button is pressed.
As the button pressed while counting the time,the button stop the counting and display "START".
I've written the code such as below.
boolean isCounting = false;
int cnt = 0;
void counter() {
while (isCounting == true) {
btn.setText(Integer.toString(++cnt));
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public void actionPerformed(ActionEvent e) {
if (isCounting == true) {
isCounting = false;
} else {
isCounting = true;
counter();
}
}
Of course this code doesn't satisfy the conditions because once the button is pressed then
the button is no more able to be pressed again and the counter never works.
In this code,once the button is pressed then the function "counter" is called but the value on the button never changes until the button is unpressed.
I have to make the codes satisfying the above conditions.
How do I implement it?

If I understood your question correctly, then this snippet I quickly put together should work for you.
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class Testing {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
Testing t = new Testing();
}
});
}
private Timer timer;
private JFrame frame;
private JButton btn;
private int timePassed;
public Testing() {
frame = new JFrame();
timer = new Timer(1000, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
timePassed++;
updateTimeOnButton();
}
});
btn = new JButton("START");
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (timer.isRunning()) {
timer.stop();
btn.setText("START");
} else {
timePassed = 0;
timer.start();
updateTimeOnButton();
}
}
});
frame.getContentPane().add(btn);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.setSize(new Dimension(300, 300));
}
private void updateTimeOnButton() {
btn.setText(timePassed + " seconds");
}
}

How to make jButton.setVisible() work instantaneously?

I've written a test program with making the jButton invisible and visible:
import java.awt.Dimension;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.event.*;
public class Blink
{
private JButton btn;
private static JFrame f;
public static void delay(int ms)
{
try
{
Thread.sleep(ms);
}
catch(InterruptedException ex)
{
Thread.currentThread().interrupt();
}
}
public Blink()
{
f = new JFrame("Blink");
f.setPreferredSize(new Dimension(500, 500));
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
btn = new JButton("Click me and I'll blink!");
f.add(btn);
btn.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
buttonClicked();
}
});
f.pack();
f.setVisible(true);
}
private void buttonClicked()
{
for (int i = 0; i < 5; i++)
{
delay(300);
btn.setVisible(false);
delay(300);
btn.setVisible(true);
}
}
public static void main(String[] args)
{
new Blink();
}
}
Unfortunately, the jButton does not blink. And when the buttonClicked() function is changed, so that the jButton is set invisible 5 times and is not set visible back, the jButton disappears only when the for-loop finishes. How to make the jButton disappear an reappear instantaneously?

You cannot use Thread.sleep method in Swing Thread (all listeners are called in Event Dispatcher Thread - EDT). To achieve blinking you must use javax.swing.Timer class. For more information look here and here
Here is your reworked example:
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class Blink {
private JButton btn;
private JFrame f;
public void delay(int ms, boolean show) {
Timer timer = new Timer(ms, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
btn.setVisible(show);
btn.getParent().revalidate();
btn.getParent().repaint();
}
});
timer.setRepeats(false);
timer.start();
}
public Blink() {
f = new JFrame("Blink");
f.setPreferredSize(new Dimension(500, 500));
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
btn = new JButton("Click me and I'll blink!");
f.add(btn);
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
buttonClicked();
}
});
f.pack();
f.setVisible(true);
}
private void buttonClicked() {
for (int i = 1; i <= 10; i += 2) {
delay(300 * i, false);
delay(300 * (i + 1), true);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Blink();
}
});
}
}
For some complicated layouts, call setVisible(false) may have side-effects. In this case the CardLayout with your component and an empty panel should be used.
Here is the variant with CardLayout
import java.awt.CardLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class Blink {
private static final String BUTTON_CARD = "button";
private static final String EMPTY_CARD = "empty";
private JButton btn;
private JFrame f;
private final CardLayout cardLayout = new CardLayout();
public void delay(int ms, boolean show) {
Timer timer = new Timer(ms, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
cardLayout.show(btn.getParent(), show ? BUTTON_CARD : EMPTY_CARD);
btn.getParent().revalidate();
btn.getParent().repaint();
}
});
timer.setRepeats(false);
timer.start();
}
public Blink() {
f = new JFrame("Blink");
f.setPreferredSize(new Dimension(500, 500));
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setLayout(cardLayout);
btn = new JButton("Click me and I'll blink!");
f.add(btn, BUTTON_CARD);
f.add(new JPanel(), EMPTY_CARD);
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
buttonClicked();
}
});
f.pack();
f.setVisible(true);
}
private void buttonClicked() {
for (int i = 1; i <= 10; i += 2) {
delay(300 * i, false);
delay(300 * (i + 1), true);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Blink();
}
});
}
}

As #Sergiy points out - make sure you're running from the EDT, and don't sleep on the EDT, use a swing timer instead.
To make your jButton appear "invisbile", you can do something like this:
public void setInvisible(jButton jb) {
jb.setOpaque(false);
jb.setContentAreaFilled(false);
jb.setBorderPainted(false);
jb.setText("");
}
// Assuming you have the original text saved in a variable
public void setRevisible(jButton jb) {
jb.setOpaque(true);
jb.setContentAreaFilled(true);
jb.setBorderPainted(true);
jb.setText(originalString);
}
Depending on if you want the button to be clickable when it's invisible, you can also add btn.setEnabled(bool);

How can I get a 2 second printing delay in a textarea between each letter/key that is pressed in another textarea?

I'm trying to add a 2 second delay between each letter that is typed in one textarea before it is printed/displayed on another textarea.
I've used two classes:
One for a GUI called Printdelay
One for the thread, called TwoSecondDelay
Everything works fine except for the execution of the thread.
Here's the code for the GUI:
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
public class PrintDelay extends javax.swing.JFrame implements KeyListener{
int name;
JTextArea server = new JTextArea (10, 20);
JTextArea client = new JTextArea (10, 20);
public PrintDelay () {
super ("Typing...");
setSize (650, 220);
setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel ();
server.addKeyListener (this);
panel.add (server);
panel.add (client);
add(panel);
setVisible (true);
}
public static void main (String... args) {
new PrintDelay ();
}
#Override
public void keyTyped(KeyEvent e)
{
}
#Override
public void keyPressed(KeyEvent e)
{
}
#Override
public void keyReleased(KeyEvent e)
{
new TwoSecondDelay (Integer.toString(name));
name++;
client.setText(server.getText());
}
}
Here's the code for the TwoSecondDelay:
public class TwoSecondDelay implements Runnable{
String name;
Thread t;
TwoSecondDelay (String threadname) {
name = threadname;
t = new Thread (this, name);
t.start();
}
#Override
public void run() {
try {
Thread.sleep(2000);
}
catch (InterruptedException e) {
}
}
}
Also the classes are in their own separate files.

No need to use TwoSecondDelay
#Override
public void keyReleased(KeyEvent e)
{
typeText();
/*new TwoSecondDelay (Integer.toString(name));
name++;
client.setText(server.getText());*/
}
public void typeText(){
ActionListener listener = new ActionListener(){
public void actionPerformed(ActionEvent event){
client.setText(server.getText());
}
};
Timer timer = new Timer(2000, listener);
timer.setRepeats(false);
timer.start();
}

Make a Swing Timer execute N times?

How can I adjust this Timer code so that it executes four times and then stops?
timer = new Timer(1250, new java.awt.event.ActionListener() {
#Override
public void actionPerformed(java.awt.event.ActionEvent e) {
System.out.println("Say hello");
}
});
timer.start();

You could do:
Timer timercasovac = new Timer(1250, new ActionListener() {
private int counter;
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("Say hello");
counter++;
if (counter == 4) {
((Timer)e.getSource()).stop();
}
}
});
timercasovac.start();

You need to count yourself and then stop the Timer manually:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class TestTimer {
private int count = 0;
private Timer timer;
private JLabel label;
private void initUI() {
JFrame frame = new JFrame("test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
label = new JLabel(String.valueOf(count));
frame.add(label);
frame.pack();
frame.setVisible(true);
timer = new Timer(1250, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (count < 4) {
count++;
label.setText(String.valueOf(count));
} else {
timer.stop();
}
}
});
timer.start();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new TestTimer().initUI();
}
});
}
}

Multithreading program not working

I am trying to make this work. I create a window, with one text field and button, then I run the run() method which should refresh text in textfield, and when I click on button it should iterate number by 1. I want to make this work simultaneously but I am stuck. It just iterates the number but do not refresh a value in textfield.Could you please help me somehow? I thought its easy to learn about Threads but...no :-D Here is the code.
Window class
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;
#SuppressWarnings("serial")
public class Okno extends JFrame implements ActionListener,Runnable {
private JFrame o = new JFrame();
private static JTextField t = new JTextField();
private JTextField t2 = new JTextField();
private static int x = 0;
protected JButton b = new JButton("KLIK");
Okno() {
o.setVisible(true);
o.setBounds(0, 0, 300, 200);
o.setLayout(null);
o.setDefaultCloseOperation(EXIT_ON_CLOSE);
t.setBounds(10, 10, 60, 20);
t2.setBounds(80, 10, 60, 20);
b.setBounds(50, 80, 60, 30);
b.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
while (true) {
Okno.work();
System.out.println("Klik");
}
}
});
o.add(t);
o.add(b);
o.add(t2);
}
public static int iter(){
x++;
return x;
}
public static void work(){
try {
iter();
System.out.println(x);
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
#Override
public void actionPerformed(ActionEvent e) {
}
#Override
public void run() {
while(true){
try {
Thread.sleep(1200);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
t.setText(Integer.toString(x));
System.out.println("RUN");
}
}
}
Main Class
public class ThreadDemo {
public static void main(String args[]) {
Okno o = new Okno();
while(true){
o.run();
}
}
}

Swing is single threaded. Calling Thread.sleep prevents UI updates. Use a Swing Timer instead.
From GETah's answer to java stopwatch that updates gui every second:
Something along these lines should do it:
import java.awt.EventQueue;
import java.util.Timer;
import java.util.TimerTask;
import javax.swing.JFrame;
import javax.swing.JLabel;
/** #see https://stackoverflow.com/a/11058263/230513 */
public class Clock {
private Timer timer = new Timer();
private JLabel timeLabel = new JLabel(" ", JLabel.CENTER);
public Clock() {
JFrame f = new JFrame("Seconds");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(timeLabel);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
timer.schedule(new UpdateUITask(), 0, 1000);
}
private class UpdateUITask extends TimerTask {
int nSeconds = 0;
#Override
public void run() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
timeLabel.setText(String.valueOf(nSeconds++));
}
});
}
}
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
final Clock clock = new Clock();
}
});
}
}
The timeLabel will always display the number of seconds the timer
has been running.
You will need to correctly format it to display "hh:mm:ss"; one approach is shown here.
Create a container and add the label to it so that you can display it as part of the GUI.
Compare the result to this alternate using javax.swing.Timer.