Change panel color for an interval - java

I want to create a program that when a button is clicked, a panel may or may not change it's color. I have an array of panels that will turn red if a wrong combination is chosen. But I just want to make it red for about 1-2 seconds. After that I will change again the panel background to null. I want every panel to have it's own timer when it goes red. So far here is my code:
javax.swing.Timer timer = new javax.swing.Timer (250, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
pnlArray [count - 2][count2].setBackground (Color.RED);
};
});
pnlArray [count - 2][count2].setBackground (null);
This code generates an error: local variables referenced from an inner class must be final or effectively final. Obviously, pnlArray[][] is not a final panel. Thread.sleep() method however, freezes the whole program. How can I achieve this?

I found a solution to my question using java.util.Timer package. Since the Timer() class needs final to run the run() method, I assigned the JPanel to a final variable. Then I canceled the timer once the first delay is over.
final JPanel pnlChange = pnlArray [count - 2][count2];
pnlChange.setBackground (Color.RED);
java.util.Timer timer = new java.util.Timer ();
TimerTask task = new TimerTask () {
int seconds = 4;
int divisor = 0;
#Override
public void run() {
divisor++;
if (divisor % seconds == 0) {
timer.cancel ();
pnlChange.setBackground (null);
}
}
};
timer.schedule(task, 0, 1000);

Related

JDialog doesn't dispose

I'm new into programming and I'm having some trouble with this.
The problem is, I'm using the Swing palette to create an assignment where I'm using a JDialog to display a timer at the same time of another frame, when I dispose this frame to change to another and return to the previous one the timer in the JDialog overlaps the first one that was running, and I couldn't managed to fix it.
Here's the code.
MAIN
public static void main(String[] args) {
Panel0 screen=new Panel0();
screen.setTitle("");
screen.setLocationRelativeTo(screen);
screen.setVisible(true);
}
1st FRAME
public class Panel0 extends javax.swing.JFrame {
Panel s=new Panel();
private void fisica1ActionPerformed(java.awt.event.ActionEvent evt) {
s.time();
s.setTitle("FISIC I");
s.setLocationRelativeTo(s);
s.setVisible(rootPaneCheckingEnabled);
s.dialog.setVisible(rootPaneCheckingEnabled);
dispose();
}
2nd FRAME
public class Panel extends javax.swing.JFrame {
private void EndActionPerformed(java.awt.event.ActionEvent evt) {
dialog.dispose();
dialog.setDefaultCloseOperation(0);
Panel0 pan=new Panel0();
pan.setLocationRelativeTo(p1);
pan.setVisible(rootPaneCheckingEnabled);
dispose();
}
void time(){
t=new Timer(1,new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (startTime<0) {
startTime=System.currentTimeMillis();
}
long now = System.currentTimeMillis();
long clockTime = now - startTime;
if (clockTime >= duration) {
clockTime = duration;
t.stop();
}
SimpleDateFormat sdf=new SimpleDateFormat("mm:ss:SS");
clock.setText(sdf.format(duration-clockTime));
}
});
t.setInitialDelay(0);
if (!t.isRunning()) {
startTime = -1;
t.start();
}
}
I omitted the inizialization of the Timer and such, because I don't think that's the problem.
To clarify something: Once I close the 2nd frame the 1st opens and gives me options to repeat this process over and over, and everytime the JDialog named "dialog" overlaps with its data (you can see the numbers of the clock overlaping).
dispose() does not means that you will "destroy" the object or clear its state. It means that you will release graphics resources attached to that frame (low level window handle and stuff). It still can be reused with setVisible(true)
I assume that you want to reuse our popup - this is just fine, but I think that you are forgetting to stop the "disposed" timer thus every new timer you create on action will be exposed to so called "racing conditions".
Timers are simple background task and they must be stopped explicitly - it will not be done by itself.
Every call to s.time(); starts new timer without stopping previous one.
Simply speaking: you have multiple timers updating the same text field.
Solution: Stop previous timer before running new OR restart previous timer.

Timer doesn't work in java [duplicate]

I made a blackjack game, and I want the AI player to pause between taking cards. I tried simply using Thread.sleep(x), but that makes it freeze until the AI player is done taking all of his cards. I know that Swing is not thread safe, so I looked at Timers, but I could not understand how I could use one for this. Here is my current code:
while (JB.total < 21) {
try {
Thread.sleep(1000);
} catch (InterruptedException ex) {
System.out.println("Oh noes!");
}
switch (getJBTable(JB.total, JB.aces > 0)) {
case 0:
JB.hit();
break;
case 1:
break done;
case 2:
JB.hit();
JB.bet *= 2;
break done;
}
}
BTW, the hit(); method updates the GUI.
so I looked at Timers, but I could not understand how I could use one for this
The Timer is the solution, since as you say you are updating the GUI which should be done on the EDT.
I'm not sure what your concern is. You deal a card and start the Timer. When the Timer fires you decide to take another card or hold. When you hold your stop the Timer.
Well, the following code shows a JFrame with a JTextArea and a JButton. When the buttons is clicked, the Timer send the event repeatedly (with a second delay between them) to the actionListener related to the button which appends a line with the current time.
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Calendar;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.Timer;
public class TimerTest extends JFrame implements ActionListener{
private static final long serialVersionUID = 7416567620110237028L;
JTextArea area;
Timer timer;
int count; // Counts the number of sendings done by the timer
boolean running; // Indicates if the timer is started (true) or stopped (false)
public TimerTest() {
super("Test");
setBounds(30,30,500,500);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLayout(null);
area = new JTextArea();
area.setBounds(0, 0, 500, 400);
add(area);
JButton button = new JButton("Click Me!");
button.addActionListener(this);
button.setBounds(200, 400, 100, 40);
add(button);
// Initialization of the timer. 1 second delay and this class as ActionListener
timer = new Timer(1000, this);
timer.setRepeats(true); // Send events until someone stops it
count = 0; // in the beginning, 0 events sended by timer
running = false;
System.out.println(timer.isRepeats());
setVisible(true); // Shows the frame
}
public void actionPerformed(ActionEvent e) {
if (! running) {
timer.start();
running = true;
}
// Writing the current time and increasing the cont times
area.append(Calendar.getInstance().getTime().toString()+"\n");
count++;
if (count == 10) {
timer.stop();
count = 0;
running = false;
}
}
public static void main(String[] args) {
// Executing the frame with its Timer
new TimerTest();
}
}
Well, this code is a sample of how to use javax.swig.Timer objects. In relation with the particular case of the question. The if statement to stop the timer must change, and, obviously, the actions of the actionPerformed. The following fragment is a skeleton of the solution actionPerformed:
public void actionPerformed(ActionEvent e) {
if (e.getComponent() == myDealerComponent()) {
// I do this if statement because the actionPerformed can treat more components
if (! running) {
timer.start();
runnig = true;
}
// Hit a card if it must be hitted
switch (getJBTable(JB.total, JB.aces > 0)) {
case 0:
JB.hit();
break;
case 1:
break done;
case 2:
JB.hit();
JB.bet *= 2;
break done;
}
if (JB.total >= 21) { // In this case we don't need count the number of times, only check the JB.total 21 reached
timer.stop()
running = false;
}
}
}
IMHO this resolves the problem, now #user920769 must think where put the actionListener and the starting/stopping conditions...
#kleopatra: Thanks for show me the existence of this timer class, I don't know nothing about it and it's amazing, make possible a lot of tasked things into a swing application :)
Well, a quick explanation about Timers.
First of all, you need a java.util.Timer variable in your class and another class in your project which extends from java.util.TimerTask (let's call it Tasker).
The initialization of the Timer variable is so easy:
Timer timer = new Timer();
Now the Tasker class:
public class Tasker extends TimerTask {
#Override
public void run() {
actionToDo(); // For example take cards
}
// More functions if they are needed
}
Finally, the installation of the timer with its related Tasker:
long delay = 0L;
long period = pauseTime;
timer.schedule(new Tasker(),delay,period);
The schedule function indicates the following:
Fisrt param: Action to do each period milliseconds (Executes the run function of a TimerTask class or its extension)
Second param: When the timer must start. In this case, it starts when the schedule function is called. The following example indicates a starting 1 second after call the schedule function: timer.schedule(new Tasker(),1000,period);
Third param: milliseconds between one call of Tasker.run() function and the following call.
I hope you understand this microtutorial :). If you have any problem, ask for more detailed information!
Kind regards!
I think that in this tutorial is clear how to use Timers in order to achieve what you want, without having to deal with Threads.

Flashing color of a JTextField

I have a JTextField that is cleared if it has invalid content. I would like the background to flash red one or two times to indicate to the user that this has happened. I have tried:
field.setBackground(Color.RED);
field.setBackground(Color.WHITE);
But it is red for such a brief time that it cannot possibly be seen. Any tips?
The correct solution, almost arrive at by just eric, is to use a Swing Timer, since all the code in the Timer's ActionListener will be called on the Swing event thread, and this can prevent intermittent and frustrating errors from occurring. For example:
public void flashMyField(final JTextField field, Color flashColor,
final int timerDelay, int totalTime) {
final int totalCount = totalTime / timerDelay;
javax.swing.Timer timer = new javax.swing.Timer(timerDelay, new ActionListener(){
int count = 0;
public void actionPerformed(ActionEvent evt) {
if (count % 2 == 0) {
field.setBackground(flashColor);
} else {
field.setBackground(null);
if (count >= totalCount) {
((Timer)evt.getSource()).stop();
}
}
count++;
}
});
timer.start();
}
And it would be called via flashMyField(someTextField, Color.RED, 500, 2000);
Caveat: code has been neither compiled nor tested.
You need to extend public class Timer
Do it like so:
private class FlashTask extends TimerTask{
public void run(){
// set colors here
}
}
You can set Timer to execute in whatever intervals you prefer to create the flashing effect
From documentation:
public void scheduleAtFixedRate(TimerTask task, long delay, long period)
Schedules the specified task for repeated fixed-rate execution, beginning after the specified delay.

Multiple swing timers

I have (what should be) a simple problem to tackle and I'm open to other ways to solve it. I am open to other solutions.
The problem:
We are using java swing to display the graphics of a turn-based, tile-based game. I'm using jlabels with icons, absolutely positioned.
To animate the movement, I am using a swing timer that updates the location by 4 pixels at a time, slowly moving the sprite right, left, etc.
To achieve this initially, I was running a timer, which works wonderfully. The problem comes in when I try to move down, then move right.
The sprite moves down, never moves right, and if I watch the execution with some console printing, it's clear to see that both timers are running at the same time. I've done a fair amount of digging on the internet and I wasn't able to find a way to tell a swing timer not to execute until the first timer has stopped, and if I try to busy-wait until one timer finishes (yuck) the UI never displays at all (clearly a step in the wrong direction.)
Now I can convert away from timers altogether and either have the sprite teleport to its new location, or use some awful busy-wait movement scheme, but I'm hoping some kind soul has a solution.
In short: I need a way to run a swing timer for a set period of time, stop it, and then start a new timer, so that they do not overlap. Preferably this method would allow each timer to be in its own method, and I could then call the methods one after the other.
Thanks in advance for any advice you might have.
Edit: Expanded example code. If a full scsse is a requirement for your advice then I'm sorry to have wasted your time, because the full code is a beast. This sample code does not work at all as it stands, sorry, but it should illustrate the point.
So. We have two functions, each with a timer that runs an animation cycle, one for moving down and right diagonally, one for moving straight down.
public class TestClass {
static int counter = 0;
static int counter2 = 0;
static Timer timerC;
static Timer timerX;
public static void main(String[] args) {
moveC();
moveX();
}
public static void moveC() {
int delay = 200; // milliseconds
timerC = new Timer(delay, null);
timerC.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (counter < 32) {
counter = counter + 4;
System.out.println("*C*");
} else {
timerC.stop();
System.out.println("*C STOP*");
}
}
});
timerC.start();
}
public static void moveX() {
int delay = 200; // milliseconds
timerX = new Timer(delay, null);
timerX.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (counter < 32) {
counter = counter + 4;
System.out.println("*X*");
} else {
timerX.stop();
System.out.println("*X STOP*");
}
}
});
timerX.start();
}
}
What I would want to see here eventually would be
*C*
*C*
*C*
*C*
*C STOP*
*X*
*X*
*X*
*X*
*X STOP*
What I actually get is
*C*
*X*
*C*
*X*
*C*
*X*
*C*
*X*
*C STOP*
*X STOP*
The point I'm trying to get at here is running one animation cycle to completion, then the other.
Thanks again.
Don't use multiple Timers, but rather only one Timer that deals with each direction as it's needed. You need some type of queue to hold the direction information, either a formal queue or a collection that you use as a queue (first in, first out), and then have your Timer extract the direction from this queue as it's running. For example, here I use my JList's model as my queue by removing and using the Direction that was added first (at the top of the JList):
import java.awt.GridLayout;
import java.awt.event.*;
import javax.swing.*;
public class TimerPlay extends JPanel {
private DefaultListModel directionJListModel = new DefaultListModel();
private JList directionJList = new JList(directionJListModel);
JButton startTimerButton = new JButton(
new StartTimerBtnAction("Start Timer"));
public TimerPlay() {
ActionListener directionBtnListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent actEvt) {
String actionCommand = actEvt.getActionCommand();
Direction dir = Direction.valueOf(actionCommand);
if (dir != null) {
directionJListModel.addElement(dir);
}
}
};
JPanel directionBtnPanel = new JPanel(new GridLayout(0, 1, 0, 10));
for (Direction dir : Direction.values()) {
JButton dirBtn = new JButton(dir.toString());
dirBtn.addActionListener(directionBtnListener);
directionBtnPanel.add(dirBtn);
}
add(directionBtnPanel);
add(new JScrollPane(directionJList));
add(startTimerButton);
}
private class StartTimerBtnAction extends AbstractAction {
protected static final int MAX_COUNT = 20;
public StartTimerBtnAction(String title) {
super(title);
}
#Override
public void actionPerformed(ActionEvent arg0) {
startTimerButton.setEnabled(false);
int delay = 100;
new Timer(delay, new ActionListener() {
private int count = 0;
private Direction dir = null;
#Override
public void actionPerformed(ActionEvent e) {
if (count == MAX_COUNT) {
count = 0; // restart
return;
} else if (count == 0) {
if (directionJListModel.size() == 0) {
((Timer)e.getSource()).stop();
startTimerButton.setEnabled(true);
return;
}
// extract from "queue"
dir = (Direction) directionJListModel.remove(0);
}
System.out.println(dir); // do movement here
count++;
}
}).start();
}
}
private static void createAndShowGui() {
TimerPlay mainPanel = new TimerPlay();
JFrame frame = new JFrame("TimerPlay");
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();
}
});
}
}
enum Direction {
UP, DOWN, LEFT, RIGHT;
}
For reference, this example manages four instances of Timer, two of which run (interleaved) while hovering in any corner. You might compare it to your approach. This related answer discusses animation in a similar tile-based game.
put all Icons in some form of array
create a single Swing Timer with a short delay
in Swing ActionListener, take each `Icon from the array, getBounds from screen, move Icon one step
repeat until target reached.

using events and listeners properly with awt and setVisible()

Below, i have two events that are supposed to occur at their specified intervals. but as odd as it is, one is just not occuring.
class MyFrame extends JFrame implements ActionListener
{
private ActionListener listener;
private Timer t1;
private ActionListener listener2;
private Timer t2;
private String recentUpdate = "NULL";
private String recentPrinted ="NULL";
public MyFrame()
{
Dimension d = Toolkit.getDefaultToolkit().getScreenSize();// gets the maximum size of the screen
setSize(d.width,(d.height/100)*10);//sets it to max. need to change this
// this shit find the max size of screen and puts it bottom left
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
GraphicsDevice defaultScreen = ge.getDefaultScreenDevice();
Rectangle rect = defaultScreen.getDefaultConfiguration().getBounds();
int x = (int)rect.getMinX();
int y = (int)rect.getMaxY()-getHeight();
setLocation(x,y-30);
setTitle("ALERT::OUTAGE");
MyPanel panel = new MyPanel();
add(panel);
listener = this; //I THINK THIS just says wait for the timer
t1 = new Timer(50000,listener); // time for each repaint
t1.start(); //go
listener2 = this;
t2 = new Timer(10000,listener2); //time to wait before setting visible again
t2.start();
}
public void actionPerformed(ActionEvent event)
{
repaint();
}
public void newUpdate(ActionEvent q)
{
// TODO Auto-generated method stub
this.setVisible(true);
System.out.println("Woopee!");
//checkForNewUpdate();
}
Basically, I have a program which takes text from a webpage and displays it marquee style across the page. it repaints and moves 5 points left each time, allowing it to look fluid in animation.
When the frame is closed, it is hidden in the background. hide_on_close
when checkForUPdate is run, if there is an update then the page will reappear.
The probelm i have now is i can have 2 events and 2 timers. but im note sure how they work. How can i set it so that repaint will trigger on the Event and checkforUpdate() will occur on the ActionEvent q
Both timers end up triggering the same method, actionPerformed. There's nothing in your code to invoke newUpdate.
needed to define the listeners. i didnt know how to combine timers with events
listener = new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
checkForNewUpdate();
}
};
//I THINK THIS just says wait for the timer
t1 = new Timer(3000,listener); // time for each repaint
t1.start(); //go
listener2 = new ActionListener()
{
public void actionPerformed(ActionEvent q)
{repaint();}
};
t2 = new Timer(50,listener2); //time to wait before setting visible again
t2.start();
}
public void actionPerformed(ActionEvent event)
{
checkForNewUpdate();
System.out.println("Woopee!");
/**System.out.println(t2.getActionListeners().toString());*/ // just for testing
}

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