I am trying to create a spam of frames and i want to stop it when i press HOME key ,but it doesn't focus on the first frame( which i can use the keylistener on ). I tried without the first frame , just the ones in the loop with focus set on true but still doesn't work.
public class Script extends JFrame {
/**
*
*/
private static final long serialVersionUID = 1L;
public static boolean isTrue = true;
public Script(){
addKeyListener(new KeyAdapter(){
public void keyPressed(KeyEvent e){
if(e.getKeyCode() == KeyEvent.VK_HOME)
System.exit(1);
}
});
}
public static void main(String[] args) {
JFrame frames = new Script();
frames.setSize(300, 300);
frames.setVisible(true);
frames.setFocusable(true);
frames.setLocation(800, 1000);
frames.setDefaultCloseOperation(EXIT_ON_CLOSE);
while(isTrue == true){
int x = (int)(1+Math.random() * (1500-1));
int y = (int)(1+Math.random() * (900-1));
JFrame frame = new Script();
frame.setVisible(true);
frame.setFocusable(false);
frame.setSize(300, 300);
frame.setLocation(x, y);
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
}
}
}
Never use an infinite while loop like that without Thread.sleep
Related
i am trying to make a program that, when a button is pressed it will start to create many invisible frames to the point it should crash a pc. however when i try and run it the console instantly terminates
this is the code for the program:
public class JavaTester extends JFrame {
static JFrame frame;
static ImageIcon img;
private static boolean a = false;
public JavaTester() {
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(670, 700);
frame.setLocationRelativeTo(null);
frame.getContentPane().setBackground(new Color(0,255,0,0));
frame.getContentPane().setLayout(null);
frame.setUndecorated(true);
frame.setResizable(false);
frame.setVisible(true);
addKeyListener(new KeyListener() {
public void keyPressed(KeyEvent e) {
a = true;
}
public void keyReleased(KeyEvent e) {
}
public void keyTyped(KeyEvent e) {
}
});
}
public static void main(String[] args) {
do {
if (a) {
while (true)
new JavaTester();
}
} while (a = false);
}
}
is this a problem with the way my loops are ordered or is there something else that makes it instantly stop running?
Problem is here:
while (a = false);
By doing that, a is set to false.
Instead you need to use conditional operator equal to (a == false)
I created notification windows inherited from JFrame, but they appear with new icon in Windows taskbar. Is it possible to highlight main application icon when notification appears(such as in skype, when new message come) and do not show new icon in taskbar for notification window?
Here is code for popup:
public class NotificationWindow extends JFrame
{
/**
*
*/
private static final long serialVersionUID = 1L;
static private int m_count = 0;
public NotificationWindow(String text)
{
super("NotificationWindow");
setLayout(new GridBagLayout());
setSize(300, 70);
setLocationRelativeTo(null);
setOpacity(0.77f);
setUndecorated(true);
setResizable(false);
add(new JLabel(text));
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent evt)
{
--m_count;
}
});
++m_count;
}
static public int GetWindowCount()
{
return m_count;
}
static public void ShowNotificationWindow(final String text)
{
// Determine if the GraphicsDevice supports translucency.
GraphicsEnvironment graphicsEnvironment = GraphicsEnvironment
.getLocalGraphicsEnvironment();
final GraphicsDevice graphicsDevice = graphicsEnvironment
.getDefaultScreenDevice();
// If translucent windows aren't supported, exit.
if (!graphicsDevice.isWindowTranslucencySupported(TRANSLUCENT))
{
System.err.println("Translucency is not supported");
System.exit(0);
}
JFrame.setDefaultLookAndFeelDecorated(true);
// Create the GUI on the event-dispatching thread
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run()
{
NotificationWindow notificationWindow = new NotificationWindow(
text);
Insets scnMax = Toolkit.getDefaultToolkit().getScreenInsets(
notificationWindow.getGraphicsConfiguration());
int taskBarSize = scnMax.bottom;
Rectangle rect = graphicsDevice.getDefaultConfiguration()
.getBounds();
int x = (int) rect.getMaxX() - notificationWindow.getWidth();
int y = (int) rect.getMaxY() - notificationWindow.getHeight()
- taskBarSize - ((m_count - 1) % 7)
* notificationWindow.getHeight();
notificationWindow.setLocation(x, y);
notificationWindow.setVisible(true);
}
});
}
}
Don't extend a JFrame, instead extend a JDialog
In general, any application should only have a single JFrame. Other child windows should be JDialogs. See: The Use of Multiple JFrames: Good or Bad Practice?
I am creating a simple console application in which I can use keyboard arrow keys as an input like a typical remote of a toy. When I press arrow up the console will print the output text "UP" or if I press arrow down it will print "down".
I want to press the arrow key only once, i.e. I am not needed to press enter afterwards to accept my input. I want the input to be accepted automatically on pressing the arrow key.
I already tried some code but this is still not happening and I still need to press enter to accept my input. If you have any idea how I can achieve this as simple as possible, I would really appreciate it.
This sample code will helps you to get the Left Arrow Key Event. You can refer this,
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.*;
public class Test2 extends JPanel {
private static final int PREF_W = 400;
private static final int PREF_H = PREF_W;
private static final int TIMER_DELAY = 50;
private Timer leftKeyTimer = new Timer(TIMER_DELAY , new TimerListener());
public Test2() {
int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
InputMap inputMap = getInputMap(condition );
ActionMap actionMap = getActionMap();
String leftDownKey = "Left Down";
String leftUpKey = "Left Up";
KeyStroke leftDown = KeyStroke.getKeyStroke(KeyEvent.VK_LEFT , 0, false);
KeyStroke leftUp = KeyStroke.getKeyStroke(KeyEvent.VK_LEFT , 0, true);
inputMap.put(leftDown, leftDownKey);
inputMap.put(leftUp, leftUpKey);
actionMap.put(leftDownKey, new LeftKeyAction(false));
actionMap.put(leftUpKey, new LeftKeyAction(true));
leftKeyTimer.setActionCommand("Left Key");
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
private class LeftKeyAction extends AbstractAction {
private boolean onKeyRelease;
public LeftKeyAction(boolean onKeyRelease) {
this.onKeyRelease = onKeyRelease;
}
#Override
public void actionPerformed(ActionEvent e) {
if (onKeyRelease) {
if (leftKeyTimer != null && leftKeyTimer.isRunning()) {
leftKeyTimer.stop();
}
} else {
if (leftKeyTimer != null && !leftKeyTimer.isRunning()) {
leftKeyTimer.start();
}
}
}
}
private class TimerListener implements ActionListener {
public void actionPerformed(ActionEvent actEvt) {
System.out.println(actEvt.getActionCommand());
}
}
private static void createAndShowGui() {
Test2 mainPanel = new Test2();
JFrame frame = new JFrame("Test2");
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();
}
});
}
}
This is actually a surprisingly complicated problem.
If you want a true console app (no GUI elements) you have to sacrifice portability.
Most consoles are line buffered by default, so Java won't get any input until enter is pressed. Most can be switched to a character mode, but there is no OS independent way to do this. For more information see http://www.darkcoding.net/software/non-blocking-console-io-is-not-possible/
I have hit another wall. After getting my key input working, I have been racking my brains for hours, i want to create a pause function, so that if the same key is pressed again the timertask stops running (i.e the game is paused)
JPanel component = (JPanel)frame.getContentPane();
component.getInputMap().put(KeyStroke.getKeyStroke("SPACE"), "space");
component.getActionMap().put("space", (new AbstractAction(){
public void actionPerformed(ActionEvent e){
Timer timer = new Timer();
timer.scheduleAtFixedRate(new TimerTask(){
public void run(){
grid.stepGame();
}
},250, 250);
}}));
}
The problem is i cant use a global boolean isRunning var and switch it each time the key is pressed because the timerTask method in a nested class (so the boolean isRunning would have to be declared final to be accessed...). Any ideas on how to detect if the key is pressed again or if the game is already running so i can pause/cancel my timerTask.
Many Thanks Sam
Since this is a Swing game, you should be using a javax.swing.Timer or Swing Timer and not a java.util.Timer. By using a Swing Timer, you guarantee that the code being called intermittently is called on the EDT, a key issue for Swing apps, and it also has a stop method that pauses the Timer. You can also give your anonymous AbstractAction class a private boolean field to check if the key is being pressed for the first time or not.
Also, kudos and 1+ for using Key Bindings instead of a KeyListener.
e.g.,
JPanel component = (JPanel) frame.getContentPane();
component.getInputMap().put(KeyStroke.getKeyStroke("SPACE"), "space");
component.getActionMap().put("space", (new AbstractAction() {
private boolean firstPress = true;
private int timerDelay = 250;
private javax.swing.Timer keyTimer = new javax.swing.Timer(timerDelay , new ActionListener() {
// Swing Timer's actionPerformed
public void actionPerformed(ActionEvent e) {
grid.stepGame();
}
});
// key binding AbstractAction's actionPerformed
public void actionPerformed(ActionEvent e) {
if (firstPress) {
keyTimer.start();
} else {
keyTimer.stop();
}
firstPress = !firstPress;
}
}));
Another useful option is to perform a repeating task on key press and stop it on key release, and this can be done easily by getting the keystrokes for on press and on release:
KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0, true) // for key release
KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0, false) // for key press
For example:
import java.awt.event.*;
import javax.swing.*;
public class SwingTimerEg2 {
private JFrame frame;
private Grid2 grid = new Grid2(this);
private JTextArea textarea = new JTextArea(20, 20);
private int stepCount = 0;
public SwingTimerEg2() {
frame = new JFrame();
textarea.setEditable(false);
frame.add(new JScrollPane(textarea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
setUpKeyBinding();
}
void setUpKeyBinding() {
final int timerDelay = 250;
final Timer keyTimer = new Timer(timerDelay, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
grid.stepGame();
}
});
JPanel component = (JPanel) frame.getContentPane();
final int condition = JComponent.WHEN_IN_FOCUSED_WINDOW;
final String spaceDown = "space down";
final String spaceUp = "space up";
component.getInputMap(condition).put(KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0, false), spaceDown);
component.getActionMap().put(spaceDown, (new AbstractAction() {
public void actionPerformed(ActionEvent e) {
keyTimer.start();
}
}));
component.getInputMap(condition).put(KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0, true), spaceUp);
component.getActionMap().put(spaceUp, (new AbstractAction() {
public void actionPerformed(ActionEvent e) {
keyTimer.stop();
}
}));
}
public void doSomething() {
textarea.append(String.format("Zap %d!!!%n", stepCount));
stepCount ++;
}
private static void createAndShowGui() {
new SwingTimerEg2();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class Grid2 {
private SwingTimerEg2 stEg;
public Grid2(SwingTimerEg2 stEg) {
this.stEg = stEg;
}
void stepGame() {
stEg.doSomething();
}
}
Easiest and dirty solution:
final boolean[] isRunning = new boolean[1];
You don't want to do that—but it works assuming proper synchronization around.
What would be better is
final AtomicBoolean isRunning = new AtomicBoolean();
What would be even better is to review the design once again: global state usually means, "global problems"
The final qualifier requirement can easily be avoided -- replace your inner method (which has the final requirement) with a call to a class method.
No you got the wrong idea about WHY you need final for anonymous classes! Final is only needed for local variables (well more exactly any variable that might have a live time shorter than the given object).
Hence a static variable in a class is perfectly fine and will work perfectly!
Edit: example:
public class Main {
interface Test {
void call();
}
public static volatile boolean running = true;
public static void main(String[] args) {
Test t = new Test() {
#Override
public void call() {
System.out.println(Main.running);
}
};
t.call();
running = false;
t.call();
}
}
Keep a reference to the Timer somewhere, say in your game class.
When the game is paused cancel the Timer.
This will cancel any currently scheduled tasks.
Then when the game is unpaused schedule the timer again as you have done above.
public class Game {
private Timer timer;
public void pause() {
if (timer != null) {
timer.pause();
}
}
public void startOrResumeGame() {
if (timer == null) {
timer = new Timer();
} else {
// Just in case the game was already running.
timer.cancel();
}
timer.scheduleAtFixedRate(new TimerTask() {
public void run() {
grid.stepGame();
}
}, 250, 250);
}
}
I've got a "status" JLabel in one class (named Welcome) and the timer in another one (named Timer). Right now, the first one displays the word "status" and the second one should be doing the countdown. The way I would like it to be, but don't know how to - display 10, 9, 8, 7 ... 0 (and go to the next window then). My attempts so far:
// class Welcome
setLayout(new BorderLayout());
JPanel area = new JPanel();
JLabel status = new JLabel("status");
area.setBackground(Color.darkGray);
Font font2 = new Font("SansSerif", Font.BOLD, 25);
status.setFont(font2);
status.setForeground(Color.green);
area.add(status, BorderLayout.EAST); // can I put it in the bottom-right corner?
this.add(area);
and the timer:
public class Timer implements Runnable {
// public void runThread() {
// new Thread(this).start();
// }
public void setText(final String text) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
setText(text); // link to status here I guess
}
});
}
public void run() {
for (int i = 10; i > 0; i--) {
// set the label
final String text = "(" + i + ") seconds left";
setText(text);
// // sleep for 1 second
// try {
// Thread.currentThread();
// Thread.sleep(1000);
// } catch (Exception ex) {
// }
}
// go to the next window
UsedBefore window2 = new UsedBefore();
window2.setVisible(true);
}
public static void main(String[] args) {
// TODO Auto-generated method stub
// runThread();
}
} // end class
I agree that you should consider using a "Java" Timer as per Anh Pham, but in actuality, there are several Timer classes available, and for your purposes a Swing Timer not a java.util.Timer as suggested by Anh would suit your purposes best.
As for your problem, it's really nothing more than a simple problem of references. Give the class with the label a public method, say setCountDownLabelText(String text), and then call that method from the class that holds the timer. You'll need to have a reference of the GUI class with the timer JLabel in the other class.
For example:
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class Welcome extends JPanel {
private static final String INTRO = "intro";
private static final String USED_BEFORE = "used before";
private CardLayout cardLayout = new CardLayout();
private JLabel countDownLabel = new JLabel("", SwingConstants.CENTER);
public Welcome() {
JPanel introSouthPanel = new JPanel();
introSouthPanel.add(new JLabel("Status:"));
introSouthPanel.add(countDownLabel);
JPanel introPanel = new JPanel();
introPanel.setPreferredSize(new Dimension(400, 300));
introPanel.setLayout(new BorderLayout());
introPanel.add(new JLabel("WELCOME", SwingConstants.CENTER), BorderLayout.CENTER);
introPanel.add(introSouthPanel, BorderLayout.SOUTH);
JPanel usedBeforePanel = new JPanel(new BorderLayout());
usedBeforePanel.setBackground(Color.pink);
usedBeforePanel.add(new JLabel("Used Before", SwingConstants.CENTER));
setLayout(cardLayout);
add(introPanel, INTRO);
add(usedBeforePanel, USED_BEFORE);
new HurdlerTimer(this).start();
}
private static void createAndShowUI() {
JFrame frame = new JFrame("Welcome");
frame.getContentPane().add(new Welcome());
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() {
public void run() {
createAndShowUI();
}
});
}
public void setCountDownLabelText(String text) {
countDownLabel.setText(text);
}
public void showNextPanel() {
cardLayout.next(this);
}
}
class HurdlerTimer {
private static final int TIMER_PERIOD = 1000;
protected static final int MAX_COUNT = 10;
private Welcome welcome; // holds a reference to the Welcome class
private int count;
public HurdlerTimer(Welcome welcome) {
this.welcome = welcome; // initializes the reference to the Welcome class.
String text = "(" + (MAX_COUNT - count) + ") seconds left";
welcome.setCountDownLabelText(text);
}
public void start() {
new Timer(TIMER_PERIOD, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (count < MAX_COUNT) {
count++;
String text = "(" + (MAX_COUNT - count) + ") seconds left";
welcome.setCountDownLabelText(text); // uses the reference to Welcome
} else {
((Timer) e.getSource()).stop();
welcome.showNextPanel();
}
}
}).start();
}
}
Since you're using Swing you should use the javax.swing.Timer, not the java.util.Timer. You can set the timer to fire at 1 second (1000 ms) intervals and have your listener do the updating. Since Swing updates must take place in the event dispatch thread your listener is the perfect place for status.setText.
there's already a Timer class in java: http://www.exampledepot.com/egs/java.util/ScheduleRepeat.html
Why not put the setText method in the welcome class and just do 'status.setText(text)'?
And you might try BorderLayout.SOUTH or .PAGE END or .LINE END to get the timer in the lower right corner