I've created a series of classes to try and figure out Observer patterns and am having some trouble.
The two classes in the observer/observed relationship are ClockPanel, and TheTimer. TheTimer is a (swing) timer which keeps track of time from start in seconds. ClockPanel is a GUI (swing) which has a button to start the timer and a JLabel which I want to display the time.
The goal of my observer pattern: take the value being created in TheTimer and print it on my GUI.
The current problem: The timer is updating the time just fine, but I do not seem to understand how to update the value in my GUI.
I found a question similar to this one in a C# discussion, but the problem was more nuanced and way over my head.
Here are the five classes which comprise the program:
1. The GUI-ClockPanel
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class ClockPanel implements Observer {
JFrame frame;
JPanel panel;
JButton sbutton;
JLabel label;
#Override
public void update(int counter) {
String clockval = String.valueOf(counter);
label.setText(clockval);
}
public ClockPanel() {
frame = new JFrame();
frame.setSize(100, 100);
panel = new JPanel();
label = new JLabel();
TheTimer myTimer = new TheTimer();
sbutton = new JButton("start");
sbutton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
myTimer.StartTimer();
}
});
frame.setLayout(new FlowLayout());
frame.add(panel);
frame.add(sbutton);
frame.add(label);
frame.setVisible(true);
}
}
2. The Swing Timer-TheTimer
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import javax.swing.JPanel;
import javax.swing.Timer;
public class TheTimer extends JPanel implements Subject {
private ActionListener action;
private Timer Time;
private int delay = 1000;
private ArrayList<Observer> observers = new ArrayList<Observer>();
private int counter = 0;
public TheTimer() {
action = new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println(counter);
counter++;
setCounter(counter);
}
};
}
public void StartTimer() {
Time = new Timer(delay, action);
Time.setInitialDelay(0);
Time.start();
}
public int getCounter() {
return counter;
}
public void setCounter(int counter) {
this.counter = counter;
notifyObservers();
}
#Override
public void registerObserver(Observer observer) {
observers.add(observer);
}
#Override
public void removeObserver(Observer observer) {
observers.remove(observer);
}
#Override
public void notifyObservers() {
for (Observer ob : observers) {
System.out.println("Notifying ClockPanel on change in counter value");
ob.update(this.counter);
}
}
}
3. The Observer-Observer
public interface Observer {
public void update(int counter);
}
4. The Observer-related methods-Subject
public interface Subject {
public void registerObserver(Observer observer);
public void removeObserver(Observer observer);
public void notifyObservers();
}
5. The Main-TestMain
import javax.swing.SwingUtilities;
public class TestMain {
public static void main(String args[]) {
ClockPanel panel = new ClockPanel();
TheTimer timer = new TheTimer();
timer.registerObserver(panel);
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new ClockPanel();
}
});
}
}
You have two TheTimer objects: one in ClockPanel, the other in TestMain#main().
You need to remove the timer from (say) main() and add:
myTimer.registerObserver(this);
to your ClockPanel constructor.
Related
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);
I am trying to make a game engine. I have made the Game class but the error resides in the KeyBoard class. Here I leave some code.
Class:: Game
package transfer2pc.co.cc.game.tileengine;
import java.awt.Graphics;
import java.util.HashMap;
import javax.swing.JPanel;
import transfer2pc.co.cc.game.tileengine.input.KeyBoard;
public abstract class Game extends JPanel implements Runnable {
/**
*
*/
private static final long serialVersionUID = 640206679500196209L;
HashMap<String, ?> maps = null;
KeyBoard keyBoard = null;
public Game(){
super();
keyBoard = new KeyBoard(this);
setKeyBoard(keyBoard);
Thread th = new Thread(this);
th.start();
}
public void run(){
while(true){
repaint();
try {
Thread.sleep(30);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
#Override
public void paint(Graphics g){
}
public void addMap(){
}
public void setMap(){
}
public abstract void keyPressed(int code);
public abstract void keyReleased(int code);
public abstract void keyTyped(int code);
public void setKeyBoard(KeyBoard key){
addKeyListener(key);
}
}
Class:: KeyBoard
package transfer2pc.co.cc.game.tileengine.input;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import transfer2pc.co.cc.game.tileengine.Game;
public class KeyBoard extends KeyAdapter implements KeyListener {
Game game = null;
public KeyBoard(Game gm){
this.game = gm;
}
#Override
public void keyPressed(KeyEvent e) {
System.out.println("KeyPressed");
game.keyPressed(e.getKeyCode());
}
#Override
public void keyReleased(KeyEvent e) {
game.keyReleased(e.getKeyCode());
}
#Override
public void keyTyped(KeyEvent e) {
game.keyTyped(e.getKeyCode());
}
public static char getChar(int key){
return (char)key;
}
}
Class:: KeyTest
package transfer2pc.co.cc.game.tileengine.test;
import java.awt.Graphics;
import javax.swing.JFrame;
import transfer2pc.co.cc.game.tileengine.Game;
import transfer2pc.co.cc.game.tileengine.input.KeyBoard;
public class KeyTest extends Game {
/**
*
*/
private static final long serialVersionUID = 8557676950779023327L;
char pressed;
public KeyTest(){
super();
addKeyListener(new KeyBoard(this));
}
#Override
public void keyPressed(int code) {
pressed = KeyBoard.getChar(code);
}
#Override
public void keyReleased(int code) {
}
#Override
public void keyTyped(int code) {
}
#Override
public void paint(Graphics g){
g.drawString("You pressed: "+pressed, 20, 20);
}
public static void main(String[] args){
JFrame frame = new JFrame("KeyTest");
frame.setSize(640, 480);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.add(new KeyTest());
frame.setVisible(true);
}
}
But the error was there was no exception thrown and the input isn't being read. Could anybody say me the correct way of doing this..
Simply, your panel needs to be focusable. Add in wherever you create the panel:
panel.setFocusable(true);
panel.requestFocusInWindow();
Here's a SSCCE (I suggest asking questions with one of these in the future):
import java.awt.Dimension;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class SimpleKeyTest {
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
frame.getContentPane().add(panel);
panel.addKeyListener(new KeyListener() {
#Override
public void keyTyped(KeyEvent e) {}
#Override
public void keyReleased(KeyEvent e) {}
#Override
public void keyPressed(KeyEvent e) {
System.out.println("Pressed " + e.getKeyChar());
}
});
panel.setFocusable(true);
panel.requestFocusInWindow();
frame.setSize(new Dimension(300, 300));
frame.setVisible(true);
}
};
SwingUtilities.invokeLater(r);
}
}
Also, https://www.google.com/search?q=jpanel+keylistener
You can add the key listener to the JFrame, that's something I've done in the past.
It's probably not a good idea however if you have other components in the JFrame.
I'm working on an assignment for Java subject. I'm using NetBean IDE. My assignment requests me to make a word game. The game I'm designing involves a timer with delay of 1000 ms. The timer decrements a variable from 30 to 0. The timer itself is working. It is placed in the main function of GUI class. The problem I'm facing that I don't know how I'm supposed to update a jTextfield with everytime the variable is decremented.
public static void main(String args[]) {
Time counter=new Time();
ActionListener actListner = new ActionListener() {
public void actionPerformed(ActionEvent event) {
counter.decTime();
jTime.setText("Time left: " + counter.getTime());
}
};
Timer timer = new Timer(1000, actListner);
timer.start();
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new StartGUI().setVisible(true);
}
});
}
I'm not sure how to implement this properly
jTime.setText("Time left: " + counter.getTime());
Not sure what you're doing wrong (that's why you should always provide a short example that we can copy-paste-compile-run that demonstrates the problem. When I make the code runnable, it works fine. That's why we need to be able to run your code to see where you're going wrong.
Here's the runnable version:
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.Timer;
public class StartGUI extends JFrame {
static JTextField jTime = new JTextField(10);
public StartGUI() {
jTime.setEditable(false);
add(jTime);
setLayout(new GridBagLayout());
setSize(200, 200);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setLocationRelativeTo(null);
}
static class Time {
int time = 1000;
void decTime() {
time--;
}
int getTime() {
return time;
}
}
public static void main(String args[]) {
Time counter = new Time();
ActionListener actListner = new ActionListener() {
public void actionPerformed(ActionEvent event) {
counter.decTime();
jTime.setText("Time left: " + counter.getTime());
}
};
Timer timer = new Timer(1000, actListner);
timer.start();
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new StartGUI().setVisible(true);
}
});
}
}
Here is the code refactored a bit with some better practices
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.Timer;
public class StartGUI extends JFrame {
private JTextField jTime = new JTextField(10);
private Timer timer = createTimer(1000);
public StartGUI() {
jTime.setEditable(false);
add(jTime);
setLayout(new GridBagLayout());
pack();
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setLocationRelativeTo(null);
}
private Timer createTimer(int delay) {
Timer timer = new Timer(delay, new ActionListener(){
Time counter = new Time(30);
public void actionPerformed(ActionEvent e) {
if (counter.getTime() == 0) {
((Timer)e.getSource()).stop();
jTime.setText("Times up!");
} else {
jTime.setText("Time left: " + counter.getTime());
counter.decTime();
}
}
});
timer.setInitialDelay(0);
return timer;
}
private Timer getTimer() {
return timer;
}
static class Time {
int time = 1000;
public Time(int time) {
this.time = time;
}
void decTime() {
time--;
}
int getTime() {
return time;
}
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
StartGUI start = new StartGUI();
start.setVisible(true);
start.getTimer().start();
}
});
}
}
My t.stop(); method is not working. I am going crazy trying to figure out why my stop method is not working.
I'm using the a timer in my code and I can't get it to stop. Can anyone take a look at it and tell me what's going on?:
/*Gilberto Rose*/
package homework2;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class MultipleBalls extends JFrame implements ActionListener
{
int dx = 2;
int dy = 2;
int x = 1;
int y = 1;
int i = 0;
public static void main(String[] args)
{
Runnable balls = new Ball2();
Thread thread1 = new Thread(balls);
thread1.run();
}
#Override
public void actionPerformed(ActionEvent arg0)
{
repaint();
System.out.println(i++);
}
}// End of Ball class
class Ball2 extends JPanel implements Runnable
{
MultipleBalls b = new MultipleBalls();
JButton g = new JButton("resume");
JButton f = new JButton("suspend");
JButton e = new JButton("-1");
JButton d = new JButton("+1");
List<Ball2> L = new ArrayList<Ball2>();
Timer t = new Timer(50, b);
public int x = 6;
public void loopstop()
{
t.stop();
}// end of loopstop method
Ball2()
{
controller4();
controller3();
controller2();
controller();
add(d);
add(e);
add(f);
add(g);
}// End of Ball2 constructor
public void run()
{
Ball2 c = new Ball2();
b.setSize(500, 500);
b.setVisible(true);
b.add(c);
t.start();
} // End of run method
public void controller()
{
d.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
L.add(new Ball2());
}
});
}// End of controller
public void controller2()
{
e.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.out.println("subtracter");
L.remove(L.size()-1);
}
});
}// End of controller2
public void controller3()
{
f.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
loopstop();
}
});
}// End of controller3
public void controller4()
{
g.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.out.println("Resume");
}
});
}// End of controller4
public void paintComponent(Graphics g)
{
if(L.size() > 0)
{
int i = 0;
do
{
g.fillOval(L.get(i).ballx(), L.get(i).bally(), 90, 90);
i++;
}while(i < L.size() && true ); // End of Do while loop
}// End of if statement
}// End of paintComponent
MultipleBalls bb = new MultipleBalls();
public int ballx()
{
if (bb.x == 0 || bb.x == 500)
{
bb.dx *= -1;
} // End of if statement
bb.x += bb.dx;
return bb.x;
}
public int bally()
{
if (bb.y == 0 || bb.y == 500 )
{
bb.dy *= -1;
}// end of if statement
bb.y += bb.dy;
return bb.y;
}// End of bally
}// End of Ball2 class
Your code is extremely convoluted, I believe that it's suffering from something called cyclomatic complexity, so much so, it is difficult for you or us to see what object is creating what other object, and what is running what. And this is your problem. You have at least two MultipleBall objects, two Ball2 objects, and you're starting the Timer for one of the Ball2 objects and stopping it for the other.
The solution: simplify this code greatly.
Create one MultipleBalls object, just one.
Don't have MultipleBalls implement ActionListener. Rather use an anonymous inner class for your ActionListener and create it on the spot where you need it.
Create just one Ball2 object, just one.
Also note that you almost never call run() on a Thread object but rather start(), but having said that, I'm not even sure that you should be using a Thread object where you're using it.
Edit
My main class would be simple, and would simply have a main method and supporting method that gets things started. Something like:
public class MultipleBalls {
private static void createAndShowGui() {
BallsPanel mainPanel = new BallsPanel();
JFrame frame = new JFrame("Multiple Balls");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
Edit
For an example of a separation of concerns:
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.swing.*;
public class MultipleBallsZ {
private static void createAndShowGui() {
BallsPanelZ ballsPanel = new BallsPanelZ();
new Control(ballsPanel);
JFrame frame = new JFrame("Multiple Balls");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(ballsPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
#SuppressWarnings("serial")
class BallsPanelZ extends JPanel {
private static final int TIMER_DELAY = 200;
private static final int PREF_W = 400;
private static final int PREF_H = PREF_W;
private Timer timer = new Timer(TIMER_DELAY, new TimerListener());
private int counter = 0;
private Control control = null;
public BallsPanelZ() {
timer.start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
public Timer getTimer() {
return timer;
}
private class TimerListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
counter++;
System.out.printf("Count: %03d%n", counter);
}
}
public void setControl(Control control) {
this.control = control;
for (Action action : control) {
add(new JButton(action));
}
}
}
#SuppressWarnings("serial")
class Control implements Iterable<Action> {
private List<Action> actionList = new ArrayList<>();
private BallsPanelZ ballsPanel;
public Control(BallsPanelZ ballsPanel) {
actionList.add(new PauseAction());
actionList.add(new ResumeAction());
this.ballsPanel = ballsPanel;
ballsPanel.setControl(this);
}
private class PauseAction extends AbstractAction {
public PauseAction() {
super ("Timer Pause");
putValue(MNEMONIC_KEY, KeyEvent.VK_P);
}
#Override
public void actionPerformed(ActionEvent e) {
ballsPanel.getTimer().stop();
}
}
private class ResumeAction extends AbstractAction {
public ResumeAction() {
super("Timer Resume");
putValue(MNEMONIC_KEY, KeyEvent.VK_R);
putValue(DISPLAYED_MNEMONIC_INDEX_KEY, 6);
}
#Override
public void actionPerformed(ActionEvent e) {
ballsPanel.getTimer().restart();
}
}
#Override
public Iterator<Action> iterator() {
return actionList.iterator();
}
}
I want to have the user press a button to kick off a background thread.
While the thread is processing, I want two things to happen:
1) A WAIT_CURSOR should be displayed.
2) The application should not respond to mouse events.
As per the setCursor documentation "This cursor image is displayed when the contains method for this component returns true for the current cursor location, and this Component is visible, displayable, and enabled. ".
I want my application to be disabled while this background thread is processing.
Any ideas how to get the functionality I want?
import java.awt.Component;
import java.awt.Cursor;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class WaitCursor extends JFrame
{
private static final long serialVersionUID = 1L;
public WaitCursor()
{
setResizable(false);
setName(getClass().getSimpleName());
setTitle("My Frame");
setSize(300, 300);
getContentPane().add(new MyButtonPanel());
}
private class MyButtonPanel extends JPanel
{
private static final long serialVersionUID = 1L;
public MyButtonPanel()
{
JButton btnStart = new JButton("Start");
btnStart.addActionListener(new BtnStartActionListener());
add(btnStart);
}
private class BtnStartActionListener implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
// Change to WAIT_CURSOR
Component root = SwingUtilities.getRoot((JButton) e.getSource());
JOptionPane.showMessageDialog(root, "Wait 10 seconds");
root.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
// TODO: Disabling the root component prevents the WAIT_CURSOR from being displayed
root.setEnabled(false);
new Thread(new TimeKiller(root)).start();
}
}
}
private class TimeKiller implements Runnable
{
Component _root;
public TimeKiller(Component root)
{
_root = root;
}
public void run()
{
try
{
Thread.sleep(10 * 1000);
}
catch (InterruptedException e)
{
// Ignore it
}
// Change back to DEFAULT CURSOR
JOptionPane.showMessageDialog(_root, "Done waiting");
_root.setCursor(Cursor.getDefaultCursor());
_root.setEnabled(true);
}
}
private static void createAndShowGUI()
{
// Create and set up the window.
WaitCursor frame = new WaitCursor();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
try
{
createAndShowGUI();
}
catch (Exception e)
{
e.printStackTrace();
System.exit(0);
}
}
});
}
}
One way to disable it is to use the glass pane to block mouse input.
For example:
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.MouseAdapter;
import javax.swing.*;
#SuppressWarnings("serial")
public class WaitCursor2 extends JPanel {
private static final int PREF_W = 400;
private static final int PREF_H = PREF_W;
private JComponent glassPane;
private JButton runBackgroundProcBtn;
private JTextArea textarea = new JTextArea(15, 30);
public WaitCursor2(JComponent glassPane) {
this.glassPane = glassPane;
glassPane.setFocusable(true);
glassPane.addMouseListener(new MouseAdapter() {
}); // so it will trap mouse events.
add(new JTextField(10));
add(runBackgroundProcBtn = new JButton(new AbstractAction(
"Run Background Process") {
#Override
public void actionPerformed(ActionEvent arg0) {
runBackgroundProcessAction();
}
}));
add(new JScrollPane(textarea));
}
private void runBackgroundProcessAction() {
disableSystem(true);
glassPane.setVisible(true);
new SwingWorker<Void, Void>() {
#Override
protected Void doInBackground() throws Exception {
long sleepTime = 5000;
Thread.sleep(sleepTime);
return null;
}
#Override
protected void done() {
disableSystem(false);
}
}.execute();
}
public void disableSystem(boolean disable) {
glassPane.setVisible(disable);
runBackgroundProcBtn.setEnabled(!disable);
if (disable) {
System.out.println("started");
glassPane.requestFocusInWindow(); // so can't add text to text components
glassPane.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
} else {
System.out.println("done");
glassPane.setCursor(Cursor.getDefaultCursor());
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
private static void createAndShowGui() {
JFrame frame = new JFrame("WaitCursor2");
WaitCursor2 mainPanel = new WaitCursor2((JComponent) frame.getGlassPane());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
The glass pane will trap mouse events if it set visible and given a MouseListener. It will lose t his ability if it is set invisible. Likewise it will pull the caret from text components if you make it focusable and give it focus.
added a field current_active and at method actionPerformed, do a simple check. Albeit it is not perfect but for simple app, i think this do the trick. A crude way of solving your two requirement. :-) Hope it works for you too.
import java.awt.Component;
import java.awt.Cursor;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class WaitCursor extends JFrame
{
private static boolean current_active = false;
public WaitCursor()
{
setResizable(false);
setName(getClass().getSimpleName());
setTitle("My Frame");
setSize(300, 300);
getContentPane().add(new MyButtonPanel());
}
private class MyButtonPanel extends JPanel
{
public MyButtonPanel()
{
JButton btnStart = new JButton("Start");
btnStart.addActionListener(new BtnStartActionListener());
add(btnStart);
}
private class BtnStartActionListener implements ActionListener
{
// change to wait_cursor
public void actionPerformed(ActionEvent e)
{
if (!current_active)
{
Component root = SwingUtilities.getRoot((JButton) e.getSource());
JOptionPane.showMessageDialog(root, "Wait 10 seconds");
root.setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
// TODO: Disabling the root component prevents the WAIT_CURSOR from being displayed
//root.setEnabled(false);
current_active = true;
new Thread(new TimeKiller(root)).start();
}
}
}
}
private class TimeKiller implements Runnable
{
Component m_root;
public TimeKiller(Component p_root)
{
m_root = p_root;
}
#Override
public void run()
{
try
{
Thread.sleep(10 * 1000);
}
catch (InterruptedException e)
{
//Ignore it
}
// Change back to DEFAULT CURSOR
JOptionPane.showMessageDialog(m_root, "Done waiting");
m_root.setCursor(Cursor.getDefaultCursor());
current_active = false;
}
}
// create and setup the window.
public static void createAndShowGUI()
{
WaitCursor frame = new WaitCursor();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
try
{
createAndShowGUI();
}
catch (Exception e)
{
e.printStackTrace();
System.exit(0);
}
}
});
}
}