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How can I implement a thread that gets user input?

I've implemented a thread that get user input by keyboard. However, when user sets input my program returns an IllegalThreadStateException error, at line 23.
import java.util.Scanner;
public class Main {
static MyThread myThread = new MyThread();
static public boolean answered = false;
public static void main(String[] args) {
String s = "";
while (!s.equalsIgnoreCase("q")) {
int seconds = 0, average = 5;
if (seconds > average) {
myThread.stop();
String phrase = choosePhrase(seconds, average);
System.out.println(phrase);
Scanner keyboard = new Scanner(System.in);
s = keyboard.nextLine();
} else {
long createdMillis = System.currentTimeMillis();
myThread.start();
while (!answered && seconds < average) {
long nowMillis = System.currentTimeMillis();
seconds = (int) ((nowMillis - createdMillis) / 1000);
}
}
}
}
private static String choosePhrase(int seconds, int average) {
if (seconds > average + 10) {
return "¿D?";
} else if (seconds > average + 5) {
return "¿E?";
} else {
return "¿F?";
}
}
}
class MyThread extends Thread {
static String[] questions = {"¿A?", "¿B?", "¿C?"};
public void run() {
System.out.println("MyThread running");
Double d = Math.random() * 100;
int n = (int) (Math.ceil(d) % 3);
String question = questions[n];
System.out.println(question);
Scanner keyboard = new Scanner(System.in);
String s = keyboard.nextLine();
stop();
}
}
Why am I getting this exception? How do I make the thread gets and exits correctly to main function?

To make a thread exits proprely you have to use myThread.interrupt();

I've solved the issue with your suggestions:
import javax.swing.JOptionPane;
public class Main {
public static void main(String[] args) {
Latency latency = new Latency();
latency.start();
}
}
class Latency {
int seconds = 0, average = 5;
MyThread myThread;
ObjectToPass o = new ObjectToPass();
public void start() {
String s = "";
Thread t = null;
while (!s.equalsIgnoreCase("q")) {
// The program has just begun, or user has answered a question,
// or term has expired.
seconds = 0;
if (myThread != null) {
myThread.shutdown();
myThread = null;
}
if (o.answered) {
o.answered = false;
myThread = new MyThread(o, new String[]{"¿A?", "¿B?", "¿C?"});
} else {
myThread = new MyThread(o, new String[]{"¿D?", "¿E?", "¿F?"});
}
t = new Thread(myThread);
t.start();
long createdMillis = System.currentTimeMillis();
while (!this.o.getPlay() && seconds < average) {
long nowMillis = System.currentTimeMillis();
seconds = (int) ((nowMillis - createdMillis) / 1000);
}
}
}
}
class ObjectToPass {
boolean answered = true;
public synchronized boolean getPlay() {
return answered;
}
public synchronized void setPlay(boolean answered) {
this.answered = answered;
}
}
class MyThread implements Runnable {
ObjectToPass o;
static String[] questions;
public MyThread(ObjectToPass o, String[] questions) {
this.o = o;
this.questions = questions;
}
public void run() {
// System.out.println("MyThread running");
Double d = Math.random() * 100;
int n = (int) (Math.ceil(d) % 3);
String question = questions[n];
System.out.println(question);
// Scanner keyboard = new Scanner(System.in);
// String s = keyboard.nextLine();
Object[] options = {"Yes", "No"};
int oo = JOptionPane.showOptionDialog(null,
question, "Question", JOptionPane.YES_OPTION,
JOptionPane.NO_OPTION, null, options, options[0]);
this.o.setPlay(true);
}
public void shutdown() {
Thread.currentThread().interrupt();
return;
}
}

Lottery Program Ignores Function

I'm meant to write a program that lists one random number after the other, which it does (along with a beep). However, it ignores a fundamental function needed for the program to run correctly. The ask() function does what it implies, it asks the user to input an integer between the range (1000-9999) which is then compared to the winning number (random) to see if the user correctly guessed it and thus won. I've only recently started writing in Java so I'm not very sure if there's a basic mistake I'm making. Any help would be appreciated!
package edu.pupr.pega4;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Date;
import java.util.Scanner;
import javax.swing.JOptionPane;
import javax.swing.Timer;
public class Pega4Driver {
public static void main(String[] args) {
Pega4 test = new Pega4(2000, true);
test.start();
JOptionPane.showMessageDialog(null, "Quit program?");
JOptionPane.showMessageDialog(null, "Perdiste!!!");
System.exit(0);
}
}
class Pega4 {
private int interval; //Time interval for new number to appear
private boolean beep; //BEEP
private int number; //The input number
private int tiradas = 1; //Counter
private int winNum; //The winning number
//Constructor
public Pega4(int interval, boolean beep) {
this.interval = interval;
this.beep = beep;
}
//Returns a random number within a specified range
public double getRandomIntegerBetweenRange(double min, double max){
double x = (int)(Math.random()*((max-min)+1))+min;
return x;
}
public void start() {
class Pega4Inner implements Asker, ActionListener {
Scanner input = new Scanner(System.in);
Date now = new Date();
#Override
public void ask() {
System.out.println("Entrar numero deseado: ");
number = input.nextInt();
//Input Validation
if (number < 1000 || number > 9999)
{
System.out.println("Entrada invalida. Entrar numero deseado: ");
number = input.nextInt();
}
System.out.println(now);
}
#Override
public void actionPerformed(ActionEvent e) {
winNum = (int) getRandomIntegerBetweenRange(1000, 9999);
System.out.println("Tirada #" + (tiradas++) + ": " + winNum);
if (beep)
Toolkit.getDefaultToolkit().beep();
if (winNum == number)
{
JOptionPane.showMessageDialog(null, "Ganaste!!!");
System.exit(0);
}
}
}
ActionListener listener = new Pega4Inner();
Timer timer = new Timer(interval, listener);
timer.start();
}
}
The Pega4Inner class implements an interface named Asker created by me. Its code is as follows:
package edu.pupr.pega4;
public interface Asker {
void ask();
}

You would need to actually call your ask() method from somewhere :)
I think a proper point to do that in your current code would be in the beginning of your actionPerformed() method in Pega4Inner :
public void actionPerformed(ActionEvent e) {
ask();
winNum = (int) getRandomIntegerBetweenRange(1000, 9999);
…
EDIT
Based on your requirement to call ask() only once, one way to do it is by taking this method out of your inner class and put it in your outer class, then call it explicitly in your driver class. So your Pega4 class could look like this :
class Pega4 {
private int interval; //Time interval for new number to appear
private boolean beep; //BEEP
private int number; //The input number
private int tiradas = 1; //Counter
private int winNum; //The winning number
//Constructor
Date now = new Date();
Scanner input = new Scanner(System.in);
public Pega4(int interval, boolean beep) {
this.interval = interval;
this.beep = beep;
}
//Returns a random number within a specified range
public double getRandomIntegerBetweenRange(double min, double max) {
double x = (int) (Math.random() * ((max - min) + 1)) + min;
return x;
}
public void ask() {
System.out.println("Entrar numero deseado: ");
number = input.nextInt();
//Input Validation
while (number < 1000 || number > 9999) { // not IF here
System.out.println("Entrada invalida. Entrar numero deseado: ");
number = input.nextInt();
}
System.out.println(now);
}
public void start() {
class Pega4Inner implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
// ask();
winNum = (int) getRandomIntegerBetweenRange(1000, 9999);
System.out.println("Tirada #" + (tiradas++) + ": " + winNum);
if (beep) {
Toolkit.getDefaultToolkit().beep();
}
if (winNum == number) {
JOptionPane.showMessageDialog(null, "Ganaste!!!");
System.exit(0);
}
}
}
ActionListener listener = new Pega4Inner();
Timer timer = new Timer(interval, listener);
timer.start();
}
}
And then in your Pega4Driver class :
...
Pega4 test = new Pega4(2000, true);
test.ask();
test.start();
...

Stop, close, end, thread in java based on condition

I am not sure how to get this working. I want one this tread to stop once (startNumber == 0 || !Player.cCounting). !Player.cCounting is a boolean that is accessed. If either condition is met I want the loop to stop.
public class Console {
static long lastTime;
static boolean cCounting = true;
static long seconds = 0;
static long delta = 0;
static int startNumber = (int) Level.cookieTime / 1000;
Thread countDown;
public Console() {
cookieCountDown();
lastTime = System.currentTimeMillis();
}
public void cookieCountDown() {
countDown = new Thread(new Runnable() {
#Override
public void run() {
startNumber = (int) Level.cookieTime / 1000;
while (startNumber != 0) {
cCounting = Game.enter;
//System.out.println(cCounting);
try {
Thread.sleep(0);
} catch (InterruptedException e) {
e.printStackTrace();
}
while (startNumber > 0 && cCounting) {
long now = System.currentTimeMillis();
delta = now - lastTime;
if (delta >= 1000) {
delta = 0;
lastTime = System.currentTimeMillis();
System.out.println("cookie " + startNumber);// print countdown;
startNumber--;
System.out.println(Player.cCounting);
if (Player.cCounting = false) {
end();
}
}
}
}
}
});
countDown.start();
}
public void end() {
System.out.println(startNumber);
System.out.println(cCounting);
if (startNumber == 0 || !Player.cCounting) {
System.out.println("stop");
//countDown.interrupt();
//countDown.stop();
}
}
}

You just need to exit your loop. Replace your end(); method call with return;. and make startNumber and Player.cCounting volatile e.g. volatile static int startNumber

Class countdown timer doesn't reset

I have a class countdown timer that I want to reset but when it resets it wont start again.
Basicaly when the counter gets to 0 (when the status is "done"), sets x = 1 and then in the activity checks if x = 1 , and then the counter resets. When the reset method from within the class is called it shows that it has reset but it wont start counting again
Timer class:
public class countdown_timer {
private long pls;
private long millisInFuture;
private long countDownInterval;
private boolean status;
int x = 0;
public countdown_timer(long pMillisInFuture, long pCountDownInterval) {
this.millisInFuture = pMillisInFuture;
this.countDownInterval = pCountDownInterval;
this.pls = pMillisInFuture;
status = false;
Initialize();
}
public void Stop() {
status = false;
}
public int GetNumberX() {
return x;
}
public void Reset() {
millisInFuture = pls;
x=0;
}
public void Start() {
status = true;
}
public void Initialize() {
final Handler handler = new Handler();
Log.v("status", "starting");
final Runnable counter = new Runnable() {
public void run() {
long sec = millisInFuture / 1000;
if (status) {
if (millisInFuture <= 0) {
Log.v("status", "done");
x = 1;
} else {
Log.v("status", Long.toString(sec) + " seconds remain");
millisInFuture -= countDownInterval;
handler.postDelayed(this, countDownInterval);
}
} else {
Log.v("status", Long.toString(sec) + " seconds remain and timer has stopped!");
handler.postDelayed(this, countDownInterval);
}
}
};
handler.postDelayed(counter, countDownInterval);
}
Activity that uses the timer class:
mycounterup = new countdown_timer(startcard, 1000);
xup = mycounterup.GetNumberX();
if (xup == 1) {
mycounterup.Reset();
mycounterup.Start();
Thanks for any help.

try changing your start method as and one thing more i don't know if its a typo or what change mycounter.Start(); to mycounterup.Start();
public void Start() {
status = true;
Initialize();
}
save the counter state so that next time if you have to pause or resume the thing you are able to do it also

You should change your Reset method:
public void Reset() {
millisInFuture = pls;
x=0;
Initialize();
}

Dispatch an event to main java

I have a CountDownTimer class that when it finishes counting down it should dispatch an event to main java (or any class that uses it) letting it know it has finished.
Here is my class:
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.Label;
public class CountTimer {
private Label targetText;
private String direction;
private int minutes;
private int seconds;
private int totalSeconds;
private int timeTotal;
private int timeLoaded;
private Boolean test;
Timer timer;
public CountTimer(int min,int sec,String dir,Label targetTextField)
{
minutes = min * 60;
seconds = sec;
timeTotal = minutes + seconds;
if (dir == "down") {
totalSeconds = minutes + seconds;
}
else {
totalSeconds = 0;
}
if (targetTextField != null) {
targetText = targetTextField;
}
direction = dir;
}
public void start()
{
timer = new Timer(){
public void run(){
timeLoaded += 1;
if (direction == "up") {
totalSeconds++;
}
else {
totalSeconds--;
}
seconds = totalSeconds % 60;
minutes = (int) Math.floor(totalSeconds / 60);
String minutesDisplay = (minutes < 10) ? "0" + Integer.toString(minutes) : Integer.toString(minutes);
String secondsDisplay= (seconds < 10) ? "0" + Integer.toString(seconds): Integer.toString(seconds);
if (targetText != null) {
targetText.setText( minutesDisplay + ":" + secondsDisplay);
}
if (test=true) {
consoleLog(minutesDisplay + ":" + secondsDisplay);
}
if(timeTotal == timeLoaded) {
//DISPATCH CUSTOM EVENT TO MAIN.JAVA HERE
Window.alert("OK");
timer.cancel();
}
}
};
timer.scheduleRepeating(1000);
}
public int getTimeTotal()
{
return timeTotal;
}
public int getTimeLoaded()
{
return timeLoaded;
}
public int getProg()
{
return (int) Math.floor(timeLoaded/timeTotal*100);
}
public native final void consoleLog(String msg)/*-{
console.log(msg);
}-*/;
}
Please help, how can i do this?

I believe you are looking to implement the Publish-Subscribe pattern.
http://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern
You can allow your object to have subscribers register with it. Once you have finished your operation it can then notify the subscribers that it has finished.
Example:
public interface Subscriber {
public void notify();
}
public class Publisher {
private ArrayList<Subscriber> subscribers = new ArrayList<>();
public void addSubscriber(Subscriber s) {
subscribers.add(s);
}
public void doWork() {
System.sleep(100);
notifyAll();
}
private void notifyAll() {
for(Subscriber s : subscribers) {
s.notify();
}
}
}

There are several options.
If you have this requirement frequently, or you need to notify multiple Activities/widgets, you may consider using an EventBus:
How to use the GWT EventBus
Alternatively, your CountTimer can simply call a public static method in your main class:
MyApp.doSomething();