I am making John Conway's game of life and I cannot figure out how to change the period or in this case the timelength in the time.scheduleAtFixedRate(task, 0, timelength) in my code while the the program is running. I am trying to change the timelength using a jslider in my code but it does not change at all. In the code some of is creates the graphis which can be ignored and alot of the other code is for stuff such as jtextfields and jbutton.
//Game of Life
package ics_sad_majorproject.gameoflifejava_1;
import java.util.Timer;
import java.util.TimerTask;
import java.awt.Image;
import java.awt.Graphics;
import java.awt.Color;
import javax.swing.SwingUtilities;
public class GameOfLife extends javax.swing.JFrame {
int intperiod = 100;
int wid = 50, hei = 50;
boolean[][] currentMove = new boolean[hei][wid], nextMove = new boolean[hei][wid];
boolean play;
public static int intpopulation = 0;
Image offScrImg;
Graphics offScrGraph;
public static int intGeneration = 0;
Timer time = new Timer();
public GameOfLife() {
initComponents();
offScrImg = createImage(jPanel2.getWidth(), jPanel2.getHeight());
offScrGraph = offScrImg.getGraphics();
TimerTask task = new TimerTask(){
public void run() {
if(play == true){
intGeneration++;
jLabel6.setText( "Generation: " + intGeneration );
for(int i = 0; i < hei; i++){
for(int j = 0; j < wid; j++){
nextMove[i][j] = decide(i,j);
}
}
for(int i = 0; i < hei; i++){
for (int j = 0; j < wid; j++){
currentMove[i][j] = nextMove[i][j];
}
}
repain();
}
}
};
time.scheduleAtFixedRate(task, 0, intperiod);
repain();
}
private boolean decide(int i, int j){
int neighbors = 0;
if(j > 0){
if(currentMove[i][j-1]) neighbors++;
if(i>0) if(currentMove[i-1][j-1]) neighbors++;
if(i<hei-1) if(currentMove[i+1][j-1]) neighbors++;
}
if(j < wid - 1){
if(currentMove[i][j+1]) neighbors++;
if(i>0) if(currentMove[i-1][j+1]) neighbors++;
if(i<hei-1) if(currentMove[i+1][j+1]) neighbors++;
}
if(i>0) if(currentMove[i-1][j]) neighbors++;
if(i<hei-1) if(currentMove[i+1][j]) neighbors++;
if(currentMove[i][j]&& neighbors < 2)intpopulation--;
if(currentMove[i][j]&& neighbors > 3)intpopulation--;
if(currentMove[i][j] && neighbors == 3)intpopulation--;
if(neighbors == 3) intpopulation++;
jLabel5.setText("Population: " + Integer.toString(intpopulation));
if(neighbors == 3) return true;
if(currentMove[i][j] && neighbors == 2)return true;
return false;
}
private void repain(){
offScrGraph.setColor(Color.BLACK);
offScrGraph.fillRect(0, 0, jPanel2.getWidth(), jPanel2.getHeight());
for (int i = 0; i < hei; i++){
for (int j = 0; j < wid; j++){
if(currentMove[i][j])
{
offScrGraph.setColor(Color.getHSBColor((float) Math.random(), .8f, .8f));
int x = j * jPanel2.getWidth()/wid;
int y = i * jPanel2.getHeight()/hei;
offScrGraph.fillRect(x, y, jPanel2.getWidth()/wid, jPanel2.getHeight()/hei);
}
}
}
offScrGraph.setColor(Color.BLACK);
for (int i = 1; i < hei; i++){
int y = i * jPanel2.getHeight()/hei;
offScrGraph.drawLine(0, y, jPanel2.getWidth(), y);
}
for (int j = 1; j < wid; j++){
int x = j * jPanel2.getWidth()/wid;
offScrGraph.drawLine(x, 0, x, jPanel2.getHeight());
}
jPanel2.getGraphics().drawImage(offScrImg, 0, 0, jPanel2);
}
private void jSlider1StateChanged(javax.swing.event.ChangeEvent evt) {
jLabel4.setText(Integer.toString(jSlider1.getValue()) + " milisecounds");
intperiod = jSlider1.getValue();
}
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
currentMove = new boolean[hei][wid];
intGeneration = 0;
intpopulation = 0;
jLabel6.setText( "Generation: " + intGeneration );
jLabel5.setText( "population: " + intpopulation );
repain();
}
private void jPanel2MouseClicked(java.awt.event.MouseEvent evt) {
int j = wid * evt.getX() / jPanel2.getWidth();
int i = hei * evt.getY() / jPanel2.getHeight();
currentMove[i][j] = true;
intpopulation++;
jLabel5.setText("Population: " + Integer.toString(intpopulation));
repain();
}
private void jPanel2ComponentResized(java.awt.event.ComponentEvent evt) {
offScrImg = createImage(jPanel2.getWidth(), jPanel2.getHeight());
offScrGraph = offScrImg.getGraphics();
repain();
}
private void jPanel2MouseDragged(java.awt.event.MouseEvent evt) {
int j = wid * evt.getX() / jPanel2.getWidth();
int i = hei * evt.getY() / jPanel2.getHeight();
if(SwingUtilities.isLeftMouseButton(evt)){
currentMove[i][j] = true;
intpopulation++;
}else currentMove[i][j] = false;
}
private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
play = !play;
if(play) jButton3.setText("Pause");
else jButton3.setText("play");
repain();
}
private void jTextField4ActionPerformed(java.awt.event.ActionEvent evt) {
String text = jTextField4.getText();
hei = Integer.valueOf(text);
jTextField4.setText("Height: "+ Integer.toString(hei));
currentMove = new boolean[hei][wid];
nextMove = new boolean[hei][wid];
repain();
}
private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {
String text = jTextField1.getText();
wid = Integer.valueOf(text);
jTextField1.setText( "Width: "+ Integer.toString(wid));
currentMove = new boolean[hei][wid];
nextMove = new boolean[hei][wid];
repain();
}
}
what follows is the entire GameOfLife.java.
Please copy and paste it 1:1 in your current file.
Then recompile the project! (The 'Hammer with a broom'-button).
If you now run your app, everything is supposed to run as you wanted. It runs perfectly and without any NPEs on my machine...
// code here is used to design the Jframe
package ics_sad_majorproject.gameoflifejava_1;
import java.util.Timer;
import java.util.TimerTask;
import java.awt.Image;
import java.awt.Graphics;
import java.awt.Color;
import javax.swing.SwingUtilities;
public class GameOfLife extends javax.swing.JFrame {
int intperiod = 100;
int wid = 50, hei = 50;
boolean[][] currentMove = new boolean[hei][wid], nextMove = new boolean[hei][wid];
boolean play;
public static int intpopulation = 0;
Image offScrImg;
Graphics offScrGraph;
public static int intGeneration = 0;
Timer time = new Timer();
// DiabolicWords
// make task globally reachable in order to be able to set it from everywhere
TimerTask task;
public GameOfLife() {
initComponents();
offScrImg = createImage(jPanel2.getWidth(), jPanel2.getHeight());
offScrGraph = offScrImg.getGraphics();
// DiabolicWords
// start timer and task for the first time
this.restartTimerTask();
repain();
}
// DiabolicWords
// put the (re)creation of the TimerTask in a separate method
private void restartTimerTask() {
// DiabolicWords
// if a task already exists, cancel()
if (task != null) {
task.cancel();
}
// DiabolicWords
// create a new task
task = new TimerTask() {
public void run() {
if (play == true) {
intGeneration++;
jLabel6.setText("Generation: " + intGeneration);
for (int i = 0; i < hei; i++) {
for (int j = 0; j < wid; j++) {
nextMove[i][j] = decide(i, j);
}
}
for (int i = 0; i < hei; i++) {
for (int j = 0; j < wid; j++) {
currentMove[i][j] = nextMove[i][j];
}
}
repain();
}
}
};
// DiabolicWords
// run the new task
time.scheduleAtFixedRate(task, 0, intperiod);
}
private boolean decide(int i, int j) {
int neighbors = 0;
if (j > 0) {
if (currentMove[i][j - 1]) {
neighbors++;
}
if (i > 0) {
if (currentMove[i - 1][j - 1]) {
neighbors++;
}
}
if (i < hei - 1) {
if (currentMove[i + 1][j - 1]) {
neighbors++;
}
}
}
if (j < wid - 1) {
if (currentMove[i][j + 1]) {
neighbors++;
}
if (i > 0) {
if (currentMove[i - 1][j + 1]) {
neighbors++;
}
}
if (i < hei - 1) {
if (currentMove[i + 1][j + 1]) {
neighbors++;
}
}
}
if (i > 0) {
if (currentMove[i - 1][j]) {
neighbors++;
}
}
if (i < hei - 1) {
if (currentMove[i + 1][j]) {
neighbors++;
}
}
if (currentMove[i][j] && neighbors < 2) {
intpopulation--;
}
if (currentMove[i][j] && neighbors > 3) {
intpopulation--;
}
if (currentMove[i][j] && neighbors == 3) {
intpopulation--;
}
if (neighbors == 3) {
intpopulation++;
}
jLabel5.setText("Population: " + Integer.toString(intpopulation));
if (neighbors == 3) {
return true;
}
if (currentMove[i][j] && neighbors == 2) {
return true;
}
return false;
}
private void repain() {
offScrGraph.setColor(Color.BLACK);
offScrGraph.fillRect(0, 0, jPanel2.getWidth(), jPanel2.getHeight());
for (int i = 0; i < hei; i++) {
for (int j = 0; j < wid; j++) {
if (currentMove[i][j]) {
offScrGraph.setColor(Color.getHSBColor((float) Math.random(), .8f, .8f));
int x = j * jPanel2.getWidth() / wid;
int y = i * jPanel2.getHeight() / hei;
offScrGraph.fillRect(x, y, jPanel2.getWidth() / wid, jPanel2.getHeight() / hei);
}
}
}
offScrGraph.setColor(Color.BLACK);
for (int i = 1; i < hei; i++) {
int y = i * jPanel2.getHeight() / hei;
offScrGraph.drawLine(0, y, jPanel2.getWidth(), y);
}
for (int j = 1; j < wid; j++) {
int x = j * jPanel2.getWidth() / wid;
offScrGraph.drawLine(x, 0, x, jPanel2.getHeight());
}
jPanel2.getGraphics().drawImage(offScrImg, 0, 0, jPanel2);
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
jPanel2 = new javax.swing.JPanel();
jButton2 = new javax.swing.JButton();
jButton3 = new javax.swing.JButton();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jTextField1 = new javax.swing.JTextField();
jTextField4 = new javax.swing.JTextField();
jSlider1 = new javax.swing.JSlider();
jLabel4 = new javax.swing.JLabel();
jLabel5 = new javax.swing.JLabel();
jLabel6 = new javax.swing.JLabel();
jLabel1.setText("jLabel1");
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel2.setBackground(new java.awt.Color(102, 102, 102));
jPanel2.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
public void mouseDragged(java.awt.event.MouseEvent evt) {
jPanel2MouseDragged(evt);
}
});
jPanel2.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
jPanel2MouseClicked(evt);
}
});
jPanel2.addComponentListener(new java.awt.event.ComponentAdapter() {
public void componentResized(java.awt.event.ComponentEvent evt) {
jPanel2ComponentResized(evt);
}
});
javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
jPanel2.setLayout(jPanel2Layout);
jPanel2Layout.setHorizontalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 0, Short.MAX_VALUE)
);
jPanel2Layout.setVerticalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 387, Short.MAX_VALUE)
);
jButton2.setText("Reset");
jButton2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});
jButton3.setText("play");
jButton3.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton3ActionPerformed(evt);
}
});
jLabel2.setText("Time Slider");
jLabel3.setText("Grid: ");
jTextField1.setText("width:50");
jTextField1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jTextField1ActionPerformed(evt);
}
});
jTextField4.setText("height: 50");
jTextField4.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jTextField4ActionPerformed(evt);
}
});
jSlider1.setMajorTickSpacing(10);
jSlider1.setMaximum(500);
jSlider1.setMinimum(1);
jSlider1.setMinorTickSpacing(1);
jSlider1.setPaintTicks(true);
jSlider1.setValue(3000);
jSlider1.addChangeListener(new javax.swing.event.ChangeListener() {
public void stateChanged(javax.swing.event.ChangeEvent evt) {
jSlider1StateChanged(evt);
}
});
jLabel4.setText("100 milisecounds");
jLabel5.setText("Population : 0");
jLabel6.setText("Generation: 0");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
.addGap(323, 323, 323)
.addComponent(jLabel4))
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, layout.createSequentialGroup()
.addComponent(jButton3, javax.swing.GroupLayout.PREFERRED_SIZE, 181, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(21, 21, 21)
.addComponent(jLabel2)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jSlider1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(jLabel3)
.addGap(2, 2, 2)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 63, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jTextField4, javax.swing.GroupLayout.PREFERRED_SIZE, 66, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel5)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel6)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 129, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGap(0, 294, Short.MAX_VALUE)))
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap()
.addComponent(jPanel2, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton3)
.addComponent(jLabel2))
.addComponent(jSlider1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel3, javax.swing.GroupLayout.PREFERRED_SIZE, 17, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jTextField4, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel5)
.addComponent(jLabel6)
.addComponent(jButton2)))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel4))
);
pack();
}// </editor-fold>
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
currentMove = new boolean[hei][wid];
intGeneration = 0;
intpopulation = 0;
jLabel6.setText("Generation: " + intGeneration);
jLabel5.setText("population: " + intpopulation);
repain();
}
private void jPanel2MouseClicked(java.awt.event.MouseEvent evt) {
int j = wid * evt.getX() / jPanel2.getWidth();
int i = hei * evt.getY() / jPanel2.getHeight();
currentMove[i][j] = true;
intpopulation++;
jLabel5.setText("Population: " + Integer.toString(intpopulation));
repain();
}
private void jPanel2ComponentResized(java.awt.event.ComponentEvent evt) {
offScrImg = createImage(jPanel2.getWidth(), jPanel2.getHeight());
offScrGraph = offScrImg.getGraphics();
repain();
}
private void jPanel2MouseDragged(java.awt.event.MouseEvent evt) {
int j = wid * evt.getX() / jPanel2.getWidth();
int i = hei * evt.getY() / jPanel2.getHeight();
if (SwingUtilities.isLeftMouseButton(evt)) {
currentMove[i][j] = true;
intpopulation++;
} else {
currentMove[i][j] = false;
}
}
private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
play = !play;
if (play) {
jButton3.setText("Pause");
} else {
jButton3.setText("play");
}
repain();
}
private void jTextField4ActionPerformed(java.awt.event.ActionEvent evt) {
String text = jTextField4.getText();
hei = Integer.valueOf(text);
jTextField4.setText("Height: " + Integer.toString(hei));
currentMove = new boolean[hei][wid];
nextMove = new boolean[hei][wid];
repain();
}
private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {
String text = jTextField1.getText();
wid = Integer.valueOf(text);
jTextField1.setText("width: " + Integer.toString(wid));
currentMove = new boolean[hei][wid];
nextMove = new boolean[hei][wid];
repain();
}
private void jSlider1StateChanged(javax.swing.event.ChangeEvent evt) {
jLabel4.setText(Integer.toString(jSlider1.getValue()) + " milisecounds");
intperiod = jSlider1.getValue();
// DiabolicWords
// the intperiod was changed. Restart the timer and task.
this.restartTimerTask();
}
public static void main(String args[]) {
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(GameOfLife.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(GameOfLife.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(GameOfLife.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(GameOfLife.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new GameOfLife().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton2;
private javax.swing.JButton jButton3;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JLabel jLabel5;
private javax.swing.JLabel jLabel6;
private javax.swing.JPanel jPanel2;
private javax.swing.JSlider jSlider1;
private javax.swing.JTextField jTextField1;
private javax.swing.JTextField jTextField4;
// End of variables declaration
}