I have an application that is works fine and the JFrame for it is launched in the constructor of a GameInitializer class which takes in some config parameters. I have tried to create a GUI in which allows the user to specify these config parameters and then click submit. When the user clicks submit a new GameInitializer object is created. The error I am getting is:
Exception in thread "AWT-EventQueue-0" java.lang.Error: Cannot call invokeAndWait from the event dispatcher thread
at java.awt.EventQueue.invokeAndWait(Unknown Source)
at javax.swing.SwingUtilities.invokeAndWait(Unknown Source)
at game.player.humanplayer.view.HumanView.update(HumanView.java:43)
once submit is called this code is executed:
values assigned to parames...
new GameInitializer(userName, player, Constants.BLIND_STRUCTURE_FILES.get(blindStructure), handState);
Then code in the GameInitializer constructor is:
public GameInitializer(String playerName, AbstractPlayer opponent, String blindStructureConfig, AbstractHandState handState){
beginGame(playerName, opponent, blindStructureConfig, handState);
}
public static void beginGame(String playerName, AbstractPlayer opponent, String blindStructureConfig, AbstractHandState handState){
AbstractDealer dealer;
BlindStructure.initialize(blindStructureConfig);
AbstractPlayer humanPlayer = new HumanPlayer(playerName, handState);
AbstractPlayer[] players = new AbstractPlayer[2];
players[0] = humanPlayer;
players[1] = opponent;
handState.setTableLayout(players);
for(AbstractPlayer player : players){
player.initialize();
}
dealer = new Dealer(players, handState);
dealer.beginGame();
}
It basically cascades down and eventually calls this piece of code in the HumanView class:
public void update(final Event event, final ReadableHandState handState, final AbstractPlayer player) {
try {
SwingUtilities.invokeAndWait(new Runnable() {
public void run() {
gamePanel.update(event, handState, player);
validate();
}
});
} catch (InterruptedException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
if(event.equals(Event.HAND_ENDING)){
try {
if(handState.wonByShowdown() || handState.isSplitPot()){
Thread.sleep(3500);
}
else{
Thread.sleep(1000);
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
Do you have any idea why?
The point of invokeAndWait() is for another thread to wait for something to be done in the event dispatching thread (EDT). Since this code is already executing on the EDT, it's sufficient to call it directly rather than creating a Runnable.
So this code should not be surrounded by anything:
gamePanel.update(event, handState, player);
validate();
It looks like you're already in the Swing thread, so you're asking the Swing thread to wait while you do code in the Swing thread. This won't work. You need to remove the code surrounding
gamePanel.update(event, handState, player);
validate();
Related
tl, dr;
I have a GUI thread that creates an object of another class (the seconds class has implemented Runnable, but here we don't execute the run() method, instead, we call a normal method) and calls a method. In that method, the first thread (current thread) is called again (to show sth on the LCD), then sends some data to the Internet, and waits 3 seconds for the server response. The problem is that the information is printed after 3 seconds. I know about the stack and program counter, but I wonder if there is another option that I can do my job.
I have the main method, which runs 3 threads (for short, I just write the requisite code. Tell me to add more, if needed):
public static void main(String[] args) throws UnknownHostException, InterruptedException {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
GUI.getInstance().setVisible(true); //GUI is singleton, using swing and JFrame
} catch (Exception e) {
e.printStackTrace();
}
}
});
MQTTConnection.getInstance().tryToConnect(); //It's the connection class, which has a thread (the thread is handled by a library that keeps the connection alive. I have no threads there) and is a singleton too.
Thread t1 = new Thread(new SendDataThread()); //A thread which sends some data every 20 seconds.
t1.start();
}
And in SendDataThread, I have a function that creates some random data and sends them (using the MQTTConnection class).
This is the SendDataThread:
public class SendDataThread implements Runnable {
public void sendLog() {
boolean serverOnline = false;
StringBuilder data = new StringBuilder();
data.append(createData());
GUI.getInstance().printNeutral(data.toString()); //Prints BLACK on a `JTextPane`
if(MQTTConnection.getInstance().publishLog(MQTTConnection.getInstance().MQTT_PUBLISH_ESP_SEND_LOG, data.toString())) //This line has a 3 second timeout. If the server doesn't respond, it will return false. I've added the 3 seconds timeout too. Please continue reading.
serverOnline = true;
if(serverOnline)
GUI.getInstance().printOK("Server Submitted"); //Prints in GREEN
else
GUI.getInstance().printProblem("Check your connection!"); //Prints in RED
GUI.getInstance().printNeutral("-------------------------------------------------");
}
#Override
public void run() {
while(true) {
sendLog();
try {
Thread.sleep(20000); //sleeps 20 about seconds
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
//.....
}
And this is the 3 seconds timeout method, in MQTTConnection:
boolean publishLog(String topic, String data){
mqtt_responds = false;
publish(topic, data);
System.out.println("MQTT is connected");
long lastTime = System.currentTimeMillis();
while(System.currentTimeMillis() - lastTime < callback_timeout) {
if(mqtt_responds){
mqtt_responds = false;
System.out.println("Server submitted");
return true;
}
try {
Thread.sleep(200);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("Timeout");
return false;
}
Till now, everything work right. The problem starts where I have a button in the GUI class, which the user can manually send random logs:
JButton sendLogBtn = new JButton("Send Log");
sendLogBtn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
SendDataThread sdt = new SendDataThread();
sdt.sendLog();
}
});
sendLogBtn.setBounds(10, 331, 89, 23);
panel.add(sendLogBtn);
This button creates an object of SendDataThread and calls the sendLog() method. The issue happens here: after sendLog() is called, sendLog(), calls this GUI thread again:
--> GUI.getInstance().printNeutral(data.toString()); //Prints BLACK on a `JTextPane`
But the log is printed after 3 seconds (After the sendLog() method has finished working, the timeout!)
How can I fix this?
In the button's actionPerformed you are calling sendLog. sendLog does exactly what you said, ie reports some logs and waits about 3 seconds (assuming callback_timeout is about equal to 3000).
To fix this, you need to make sure that the 3sec blocking is not on the EDT and also to make sure that the logs are instead posted on the EDT.
As a quick workaround you can do:
sendLogBtn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
new Thread(() -> new SendDataThread().sendLog()).start();
}
});
and then, as always, post your logs in the EDT like for example:
SwingUtilities.invokeLater(() -> GUI.getInstance().printNeutral(...));
AND
SwingUtilities.invokeLater(() -> GUI.getInstance().printProblem(...));
AND
SwingUtilities.invokeLater(() -> GUI.getInstance().printOk(...));
As for the question in your comment, I don't really understand what you are asking, but I should say that (as far as I know) the EDT is a Thread where all the Swing code is (and should be) posted on for execution. This way the Swing code does not have to be synchronized, because all GUI related stuff is executed sequentially (on the EDT). AWT for example was not intended to be single threaded as far as I know. Swing is however single threaded.
I'm creating a program for a game that clicks in random intervals for X seconds with Y time between each click. Here is the code that does this.
try {
Util.autoCode rand = new Util.autoCode();
Robot robot = new Robot();
int NoC;
NoC = Integer.parseInt(this.numberOfClicksTF.getText().trim());
if (NoC == 0) {
while (NoC == 0) {
// robot.mousePress(InputEvent.BUTTON1_MASK);
System.out.println("Infinite Press");
Thread.sleep(rand.clickDelay());
System.out.println("Infinite Release");
// robot.mouseRelease(InputEvent.BUTTON1_MASK);
Thread.sleep(rand.interval());
break;
}
} else {
for (int i = 0; i < NoC; i++) {
//robot.mousePress(InputEvent.BUTTON1_MASK);
System.out.println("Click Press");
Thread.sleep(rand.clickDelay());
System.out.println("Click Release");
// robot.mouseRelease(InputEvent.BUTTON1_MASK);
Thread.sleep(rand.interval());
}
}
} catch (AWTException ex) {
Logger.getLogger(MainFrame.class
.getName()).log(Level.SEVERE, null, ex);
} catch (NumberFormatException ex) {
Logger.getLogger(MainFrame.class
.getName()).log(Level.SEVERE, null, ex);
} catch (InterruptedException ex) {
Logger.getLogger(MainFrame.class.getName()).log(Level.SEVERE, null, ex);
}
I commented out the mouse press and release just so I could do a check to make sure the timing was right, and that it would perform each click. This code is started by JButton in a JFrame. Whenever I press the start button, it starts the code and nothing but force closing it in Netbeans will stop it. The goal is to have a start button initiate, and a stop button interrupt the code, but not close the JFrame. I have been looking everywhere and haven't been able to find a straight answer.
Any help is welcomed and appreciated!
You need tu use SwingWorker, for example:
in your JFrame you may have a SwingWorker and it "builder" method:
private SwingWorker worker;
private SwingWorker getWorker() {
worker = worker == null ? worker = new SwingWorker() {
#Override
protected Object doInBackground() throws Exception {
while (true) {
System.out.println("doInBackground!");
Thread.sleep(1000);
}
}
} : worker;
return worker;
}
now, in the swing main thread (used for visual components updates) you need to call the SwingWorker with your background task:
private void jButtonActionPerformed(java.awt.event.ActionEvent evt) {
if (getWorker().getState().equals(SwingWorker.StateValue.STARTED)) {
worker.cancel(true);
worker = null;
} else {
getWorker().execute();
}
}
You can click on the button as many times as you wish, the app will create and run a SwingWorker or kill and set to null the current SwingWorker.
Literally ran into your exact same problem this week trying to make almost the same thing. First, let me suggest reading up on multithreading in Java. It may seem complicated, but trust me it's necessary to understand why your program is not working. (I'll give a run down of what's happening below)
Essentially, your GUI is running on an Event Dispatcher Thread that needs to be separated from your robot. That is because when you call thread.sleep(), you essentially tell the GUI thread to sleep too, resulting in loss of GUI control. Start your robot and GUI in separate threads and have your JButtons invoke methods to get your robot thread to start and stop. For example:
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
new GUI();
}
});
}
To create your GUI(I don't know what your GUI is like, so I just wrote new GUI() to substitute for how you created yours), that way it's in the thread it's supposed to be in. Then in your eventListener, spawn a new thread holding the robot object everytime the start button is pressed:
if(actionEvent.getSource().equals(playButton)) { //listening for the play button
if(robotThread == null) {
autoClicker= new AutoClicker();
Thread = new Thread(autoClicker);
Thread.start();
}
}
And initiate your robot object in the autoClicker() class like you did, and have autoClicker implement runnable.
public class AutoClicker implements Runnable{
private Robot robot;
public void run(){
try {
robot = new Robot();
} catch (AWTException e) {e.printStackTrace();}
//you need to learn about synchronization first
while(true){
synchronized(this){
//do clicks and stuff here
}
}
}
}
This way, your GUI and robots are in separate threads. In order to make JButtons start and stop your robot, you're going to need to learn synchronization to know how to properly multithread.
Another thing is that you should probably use the wait() method instead of sleep(), as sleep() would cause a lot more problems that's too much to go through in a single answer. Again, you need to learn concurrency/synchronization first.
If you want comment below and we can work out a way for me to DM you my code I'm working on right now, which is the exact same thing as you're trying to make. I can explain every part of it to you to help you on your way.
I am new to java
I have a function runner inside PhotoPoster class (PhotoPoster class is a Jframe with lots of buttons and other GUI elements)
it contains a START button when I click on START it executes the runner function which runs an activity & thats takes a very long time
and other GUI components are not accessible unless the runner functions completes.
I want this to work in separate thread or any other solution to help me
what I currently do is
I have made a another class GuiWorker.java
public class GuiWorker extends SwingWorker<Integer, Integer>{
public GuiWorker() throws IOException {
}
protected Integer doInBackground() throws Exception {
PhotoPoster photoPoster = new PhotoPoster();
photoPoster.ruuner();
return 0;
}
protected void done() {
System.out.println("done");
}
}
PhotoPoster.java
on button click
private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {
// PhotoPoster photoPoster = new PhotoPoster();
//ruuner();
EventQueue.invokeLater( new Runnable() {
#Override
public void run() {
try {
new GuiWorker().execute();
} catch (IOException ex) {
Logger.getLogger(PhotoPoster.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
it gives system out done but not performing runner function activity
Please Help me to sort out this error or any other solution
It looks as though you are queuing your long running thread back onto the Event Dispatch Thread, which means that even though you are doing invokeLater it will still block the thread.
You need to use a SwingWorker.
need to make a music player as my simple java project. it opens up a file and loads the name in the text field.when play is pressed, the name is encircled in the textfield and when pause is pressed , the encircling suspends . play pause are JTogglebuttons and i have a button names stop. using multithreading, i m able to play and pause the string but after i press Stop once.. if again i open up a new music file and press play, it shows an illegalthreadstateexception.Please help me out here.. Note: i havent yet put in the code for playing music in it.. i will put it in once this problem is solved . thanks a lot for ur
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import sun.audio.*;
public class search extends Thread implements ActionListener
{
JFrame f;
JButton stop,open;
JToggleButton play;
JTextField tf,text;
JTextArea ta;
JLabel lab,lab1;
String str,dest;
JScrollPane scrol;
File fl;
int myfl=0,myfl1=0,myfl2=0;
search()
{
f=new JFrame("Music Player");
f.setLayout(null);
f.setSize(620,300);
play=new JToggleButton("play");
play.setBounds(100,150,270,30);
play.addActionListener(this);
f.add(play);
play.setEnabled(false);
stop=new JButton("stop");
stop.setBounds(400,150,120,30);
stop.addActionListener(this);
f.add(stop);
stop.setEnabled(false);
open=new JButton("open");
open.setBounds(100,200,420,30);
open.addActionListener(this);
f.add(open);
tf=new JTextField();
tf.setBounds(25,50,565,40);
tf.setFont(new Font("DK BabySitter",Font.BOLD,20));
tf.setHorizontalAlignment(JTextField.CENTER);
f.add(tf);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void actionPerformed(ActionEvent ae)
{
if(ae.getActionCommand().equals("open"))
{
FileDialog fd=new FileDialog(f,"Open Box",FileDialog.LOAD);
fd.setSize(300,300);
fd.setVisible(true);
String s1="mp3";
str=fd.getFile();
dest=fd.getDirectory()+fd.getFile();
if(str.toLowerCase().endsWith(s1))
{
tf.setText(str);
//pause.setEnabled(true);
play.setEnabled(true);
stop.setEnabled(true);
}
else
{
JOptionPane.showMessageDialog(f, "Select a valid file format");
}
}
if(ae.getActionCommand().equals("stop"))
{
play.setLabel("play");
myfl1=1;
tf.setText(" ");
stop();
}
if(ae.getActionCommand().equals("play"))
{
try
{
play.setLabel("pause");
if(myfl==1 && myfl1==0)
{
resume();
}
if(myfl==0 || myfl1==1)
{
start();
}
}
catch(IllegalThreadStateException e)
{
tf.setText("error a gya re");
Thread newth= new Thread();
newth.start();
}
}
if(ae.getActionCommand().equals("pause"))
{
play.setLabel("play");
myfl=1;
suspend();
}
}
public void run()
{
try
{
String rot=tf.getText();
char rotn[]=new char[rot.length()];
int flag=rot.length();
int move=0;
rotn=rot.toCharArray();
tf.setText(" ");
for(;;)
{
for(;;)
{
sleep(100);
tf.setText( tf.getText() + rotn[move]);
move++;
if(move==(flag-1))
{
move=0;
break;
}
}
tf.setText(" ");
}
}
catch(Exception e)
{
tf.setText("error occured");
}
}
public static void main(String args[])
{
try {
// Set System L&F
UIManager.setLookAndFeel(
UIManager.getSystemLookAndFeelClassName());
}
catch (UnsupportedLookAndFeelException e) {
// handle exception
}
catch (ClassNotFoundException e) {
// handle exception
}
catch (InstantiationException e) {
// handle exception
}
catch (IllegalAccessException e) {
// handle exception
}
new search();
}
}
You should not use Thread.stop(), Thread.suspend() or Thread.resume(). These methods are deprecated and explicitly documented to have severe implications (like potential deadlocks etc). See also Why are Thread.stop, Thread.suspend and Thread.resume Deprecated?.
In this specific case the exception occurs because you cannot start() a Thread more than once. You need to code your thread (or better yet: don't extend Thread, but implement Runnable) so that it handles the pause, start, stop etc of your application correctly without using the deprecated and dangerous methods of Thread.
The reason you're getting this error is that you're attempting to manually manipulate the state of the thread you're running in.
The methods you're using here are all deprecated - stop, resume, suspend - these should all be avoided.
A better way to think about how your program is running is that a thread is either alive or it isnt. It may not do anything within the actual run method while alive, but at no point are you pausing/suspending/stopping the actual thread - you're only pausing/stopping the application logic within.
A very quick fix to what you're seeing is to replace all stop/suspend/resume with the following:
private volatile boolean paused = false;
private void pausePlayer(boolean pause) {
this.paused = pause;
}
then everywhere you need to pause the player use:
pausePlayer(true);
and when you want to resume it use:
pausePlayer(false);
In the run method replace the 2nd for loop with:
for (; ; ) {
while(!paused) {
// do your work
Note though that I believe there are larger structural issues with the program as it stands - mixing normal Threads with Swing can be problematic. I would suggest you investigate using a SwingWorker instead, as this is explicitly designed for the sort of thing you're trying to do.
I have a program where I am loading a file while at the same time I am displaying a window to inform the user that the file is being loaded. I decided to make a FileLoader class that was a SwingWorker which actually handled loading the file and a ProgressWindow that implements PropertyChangeListener to inform the user about the status of the SwingWorker that was passed into it.
My code currently looks like this:
FileLoader loader = new FileLoader(filePath);
new ProgressWindow(loader, "Loading File", "Loading File");
//ProgressWindow's constructor calls loader.execute() inherited from SwingWorker
doc = loader.get(); //GUI Freezes when called
The problem is that whenever I call loader.get(), it freezes the GUI, thus the progress bar in the Progress Window doesn't run and the whole thing is pointless. As far as I can tell, this is because the thread controlling the GUI is the same thread that calls loader.get(), which goes on hold while loader.execute() is running.
So far, I've tried creating a new thread for either the loader.get() command or the loader.execute() method, and calling SwingUtilities.invokeLater() on the thread, but then the whole program freezes.
I've considered creating a ChangeListener for when SwingWorker.isDone() and then running loader.get(), but this would require some reworking of my code that I would rather not do.
Could anyone tell me what the best way is to get this to work?
get() is like join() in that it will block until called, and will wait for the SwingWorker to finish before being called. Using it wrongly can completely nullify all the advantages of using a SwingWorker in the first place.
Solution: Don't call get() until you know that the SwingWorker is done with its processing, by either calling it in the SwingWorker's done() method, or if you need to call it from the calling code, then in a PropertyChangeListener that has been added to the SwingWorker when the SwingWorker's "state" property is SwingWorker.StateValue.DONE.
Something like:
final FileLoader loader = new FileLoader(filePath);
loader.addPropertyChangeListener(new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if ("state".equals(evt.getPropertyName())) {
// since DONE is enum, no need for equals(...) method
if (evt.getNewValue() == SwingWorker.StateValue.DONE) {
try {
loader.get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
}
}
});
new ProgressWindow(loader, "Loading File", "Loading File");
Note: code not compiled nor tested
Edit: try/catch added.
So far, I've tried creating a new thread for either the loader.get() command or the loader.execute() method, and calling SwingUtilities.invokeLater() on the thread, but then the whole program freezes.
If you call SwingUtilities.invokeLater() on the thread that will execute the thread in the EDT which freezes the GUI. Instead, run the thread by calling it's start() method and only use SwingUtilities.invokeLater() when you need to update the progress bar in the PropertyChangeListener.
I have create a WorkerThread class which take care of Threads and GUI current/main thread .
i have put my GUI application in construct() method of WorkerThread when an event fire to start XXXServer then all threads are activate and GUI work smoothlly wihout freeze. have a look.
/**
* Action Event
*
* #see java.awt.event.ActionListener#actionPerformed(java.awt.event.ActionEvent)
*/
public void actionPerformed(ActionEvent ae) {
log.info("actionPerformed begin..." + ae.getActionCommand());
try {
if (ae.getActionCommand().equals(btnStart.getText())) {
final int portNumber = 9990;
try {
WorkerThread workerThread = new WorkerThread(){
public Object construct(){
log.info("Initializing the Server GUI...");
// initializing the Server
try {
xxxServer = new XXXServer(portNumber);
xxxServer.start();
btnStart.setEnabled(false);
} catch (IOException e) {
// TODO Auto-generated catch block
log.info("actionPerformed() Start button ERROR IOEXCEPTION..." + e.getMessage());
e.printStackTrace();
}
return null;
}
};workerThread.start();
} catch (Exception e) {
log.info("actionPerformed() Start button ERROR..." + e.getMessage());
e.printStackTrace();
}
} else if (ae.getActionCommand().equals(btnStop.getText())) {
log.info("Exit..." + btnStop.getText());
closeWindow();
}
} catch (Exception e) {
log
.info("Error in ServerGUI actionPerformed==="
+ e.getMessage());
}
}