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I am writing a code of game bean machine(Galton box), its mechanism that one ball fall and move randomly until it get to one of the slots (randomly) and then another ball comes doing the same thing and so on, the problem is that all balls fall at the same time which something I do not want, I want each ball to fall when the current one finishes its travel..can anyone helps me ! Thanks..
here is the code:
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Random;
import java.util.Scanner;
import java.lang.Iterable;
import javax.swing.*;
public class BallPanel extends JPanel {
int x=1, y=1;
Collection <Ball> ball;
public static void main(String [] args){
// create the list
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JFrame frame= new JFrame("Bean game");
frame.add(new BallPanel());
frame.setSize(300,500);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
public BallPanel() {
JPanel panel = new JPanel();
ball=new ArrayList<>();
for(int i=1;i<=4;i++){
ball.add(new Ball(x,y));
x++;
y++;
}
Timer timer = new Timer(400, new ActionListener()
{
public void actionPerformed(ActionEvent e) {
for (Ball b: ball) {
b.move();repaint();
}
}
});
timer.start();
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int raduis=10;
int i=0;
int width=(getWidth()/8);
int space=(getWidth()-8*30)/2;
g.setColor(Color.BLACK);
for(i=0;i<=8;i++){
g.drawLine(space+(30*i),getHeight()-5*(raduis) ,space+(30*i) ,getHeight() );
if(i!=0 && i!=8)
g.fillOval(space+(30*i)-5, getHeight()-5*(raduis)-5, 10, 10);
if(i==0){
g.drawLine(space,getHeight()-5*(raduis) , space+((8)*15)-(raduis/2)-15 , getHeight()-15-(5*raduis)-(30*(8-2))-raduis/2);
g.drawLine(space+((8)*15)-(raduis/2)-15 , getHeight()-15-(5*raduis)-(30*(8-2))-raduis/2 , space+((8)*15)-(raduis/2)-15 , getHeight()/2-8*8);//vertical line
}
if(i==8){
g.drawLine(space+(30*i), getHeight()-5*(raduis), space+((8)*15)+(raduis/2)+15, getHeight()-15-(5*raduis)-(30*(8-2))-raduis/2);
g.drawLine(space+((8)*15)+(raduis/2)+15 , getHeight()-15-(5*raduis)-(30*(8-2))-raduis/2 , space+((8)*15)+(raduis/2)+15 , getHeight()/2-8*8);//vertical line
}
}
int o=1;
for(i=1;i<=8-2;i++){
int k=2;
for(int j=i;j<=8-2;j++){
g.fillOval(space+((i+k)*15)-raduis/2, getHeight()-(5*raduis)-(30*o)-raduis/2, raduis, raduis);
k=k+2;
}o++;
}
for (Ball b : ball) {
b.draw(g);
}
}
public class Ball {
Random rand=new Random();
private int n;
private int raduis = 10;
private int moveRaduis=12;
private int L = 0;
private int R = 0;
private int D = 0;
int x, y;
public Ball(int x, int y){
this.x=x;
this.y=y;
}
public void draw(Graphics g) {
g.setColor(Color.RED);
g.fillOval(getWidth()/2 -raduis/2 + R + L, 0 + D , moveRaduis, moveRaduis);
}
public void move() {
n=1+rand.nextInt(100);
if(n<=51){
D+=15;
if(D<=(getHeight()-15-(5*raduis)-(30*(8-2))-raduis/2))
L=0;
else if(D>getHeight()-15-(5*raduis)-(30*(8-2))-raduis/2 && D<getHeight()-5*(raduis))
{
D+=15;
L-=15;
}
else if(D>=getHeight()-5*(raduis))
{
if(D==31*15)D-=15;
D=D;
}
}
else if (n>=51 && n<=100){
D+=15;
if(D<=getHeight()-15-(5*raduis)-(30*(8-2))-raduis/2)
R=0;
else if(D>getHeight()-15-(5*raduis)-(30*(8-2))-raduis/2 && D<getHeight()-5*(raduis))
{
D+=15;
R+=15;
}
else if(D>=getHeight()-5*(raduis)){
if(D==31*15)D-=15;
D=D;
}
}
}
}
}
So, your movement code moves all the balls on each iteration, what you need to do is have an "active" ball, for example...
private Ball activeBall;
Timer timer = new Timer(400, new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (activeBall != null && activeBall.hasCompleted()) {
activeBall = null;
}
if (activeBall == null && ball.size() > 0) {
activeBall = ball.remove(0);
}
if (activeBall != null) {
activeBall.move();
repaint();
}
}
});
You'll need to add in some kind of check to determine the ball has completed it's run though
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I created a GUI named Menu class for my Start, Help and Exit button. my problem is my game won't start, it hangs everytime I press the Start button. Can someone check my error and explain it to me because its my case study at school.
package spaceSip;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
public class Menu extends JFrame implements ActionListener
{
private JLabel titleL;
private JButton startB, helpB, exitB;
static JFrame frame1 = new JFrame();
public Menu()
{
frame1.setSize(500,250);
Container mainP = frame1.getContentPane();
mainP.setLayout(null);
titleL = new JLabel("WELCOME");
startB = new JButton("Start");
helpB = new JButton("Help");
exitB = new JButton("Exit");
mainP.add(titleL);
titleL.setFont(new Font("Chiller",Font.BOLD,50));
titleL.setBounds(100, 30, 200, 50);
mainP.add(startB);
startB.setMnemonic(KeyEvent.VK_S);
startB.setBounds(200, 80, 100, 20);
mainP.add(helpB);
helpB.setMnemonic(KeyEvent.VK_H);
helpB.setBounds(200, 100, 100, 20);
mainP.add(exitB);
exitB.setMnemonic(KeyEvent.VK_E);
exitB.setBounds(200, 120, 100, 20);
startB.addActionListener(this);
helpB.addActionListener(this);
exitB.addActionListener(this);
frame1.setVisible(true);
frame1.setResizable(false);
}
public void actionPerformed(ActionEvent e)
{
String key = e.getActionCommand();
if(key == "Start")
{
frame1.dispose();
new SpaceShipMain();
}
else if(key == "Help")
{
}
else
System.exit(0);
}
public static void main(String[]args)
{
new Menu();
}
}
package spaceSip;
import javax.swing.*;
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
public class SpaceShipMain implements MouseListener
{
private JFrame background;
private SpaceShipPanel back;
public static boolean paused;
public static boolean crashed;
public static boolean started;
public static boolean playedOnce;
public boolean goingUp;
private double upCount;
public static int distance;
public static int maxDistance;
public final int XPOS;
public final int NUMRECS;
public final int RECHEIGHT;
public final int RECWIDTH;
private int moveIncrement;
private int numSmoke;
private ArrayList<SpaceShipImage> toprecs;
private ArrayList<SpaceShipImage> bottomrecs;
private ArrayList<SpaceShipImage> middlerecs;
private ArrayList<SpaceShipImage> smoke;
private SpaceShipImage helicopter;
public SpaceShipMain()
{
NUMRECS = 100;
RECHEIGHT = 70;
RECWIDTH = 30;
XPOS = 200;
playedOnce = false;
maxDistance = 0;
load(new File("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/Best.txt"));
initiate();
}
public void load(File file)
{
try
{
Scanner reader = new Scanner(file);
while(reader.hasNext())
{
int value = reader.nextInt();
if(value > maxDistance)
maxDistance = value;
}
}
catch(IOException i )
{
System.out.println("Error. "+i);
}
}
public void save()
{
FileWriter out;
try
{
out = new FileWriter("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/Best.txt");
out.write("" + maxDistance);
out.close();
}
catch(IOException i)
{
System.out.println("Error: "+i.getMessage());
}
}
public void initiate()
{
if(!playedOnce)
{
background = new JFrame("Space Ship Game");
background.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //closes the program when the window is closed
background.setResizable(false); //don't allow the user to resize the window
background.setSize(new Dimension(800,500));
background.setVisible(true);
back = new SpaceShipPanel("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/starfield.jpg");
background.add(back);
back.addMouseListener(this);
}
playedOnce = true;
goingUp = false;
paused = false;
crashed = false;
started = false;
distance = 0;
upCount = 0;
moveIncrement = 2;
numSmoke = 15;
toprecs = new ArrayList<SpaceShipImage>();
middlerecs = new ArrayList<SpaceShipImage>();
bottomrecs = new ArrayList<SpaceShipImage>();
smoke = new ArrayList<SpaceShipImage>();
helicopter = new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rocketship.GIF",XPOS,200);
for(int x = 0; x < NUMRECS; x++)
toprecs.add(new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rec2.JPG",RECWIDTH*x,5));
for(int x = 0; x < NUMRECS; x++)
bottomrecs.add(new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rec2.JPG",RECWIDTH*x,410));
middlerecs.add(new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid2.jpg",1392,randomMidHeight()));
middlerecs.add(new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid2.jpg",1972,randomMidHeight()));
drawRectangles();
}
public void drawRectangles()
{
long last = System.currentTimeMillis();
long lastCopter = System.currentTimeMillis();
long lastSmoke = System.currentTimeMillis();
long lastSound = System.currentTimeMillis();
int firstUpdates = 0;
double lastDistance = (double)System.currentTimeMillis();
while(true)
{
if(!paused && !crashed && started && (double)System.currentTimeMillis() - (double)(2900/40) > lastDistance)
{
lastDistance = System.currentTimeMillis();
distance++;
}
if(!paused && !crashed && started && System.currentTimeMillis() - 10 > lastCopter)
{
lastCopter = System.currentTimeMillis();
updateCopter();
updateMiddle();
}
if(!paused && !crashed && started && System.currentTimeMillis() - 100 > last)
{
last = System.currentTimeMillis();
updateRecs();
}
if(!paused && !crashed && started && System.currentTimeMillis() - 75 > lastSmoke)
{
lastSmoke = System.currentTimeMillis();
if (firstUpdates < numSmoke)
{
firstUpdates++;
smoke.add(new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/smoke.GIF",187,helicopter.getY()));
for(int x = 0; x < firstUpdates; x++)
smoke.set(x,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/smoke.GIF",smoke.get(x).getX() - 12, smoke.get(x).getY()));
}
else
{
for(int x = 0; x < numSmoke - 1; x++)
smoke.get(x).setY(smoke.get(x+1).getY());
smoke.set(numSmoke - 1,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/smoke.GIF",187,helicopter.getY()));
}
}
back.updateImages(middlerecs,helicopter,smoke);
}
}
public void updateRecs()
{
for(int x = 0; x < (NUMRECS - 1); x++) //move all but the last rectangle 1 spot to the left
{
toprecs.set(x,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rec2.JPG",RECWIDTH*x,toprecs.get(x+1).getY()));
bottomrecs.set(x,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rec2.JPG",RECWIDTH*x,bottomrecs.get(x+1).getY()));
}
}
public void randomDrop()
{
toprecs.get(26).setY(toprecs.get(26).getY() + (463 - bottomrecs.get(26).getY()));
bottomrecs.get(26).setY(463);
}
public int randomMidHeight()
{
int max = 10000;
int min = 0;
for(int x = 0; x < NUMRECS; x++)
{
if(toprecs.get(x).getY() > min)
min = (int)toprecs.get(x).getY();
if(bottomrecs.get(x).getY() < max)
max = (int)bottomrecs.get(x).getY();
}
min += RECHEIGHT;
max -= (RECHEIGHT + min);
return min + (int)(Math.random() * max);
}
//moves the randomly generated middle rectangles
public void updateMiddle()
{
if(middlerecs.get(0).getX() > -1 * RECWIDTH)
{
middlerecs.set(0,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid.gif",middlerecs.get(0).getX() - (RECWIDTH/5), middlerecs.get(0).getY()));
middlerecs.set(1,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid.gif",middlerecs.get(1).getX() - (RECWIDTH/5), middlerecs.get(1).getY()));
}
else
{
middlerecs.set(0,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid.gif",middlerecs.get(1).getX() - (RECWIDTH/5), middlerecs.get(1).getY()));
middlerecs.set(1,new SpaceShipImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/asteroid.gif",middlerecs.get(0).getX() + 580,randomMidHeight()));
}
}
public boolean shoot()
{
for(int x = 3; x <= 7; x++)
if(helicopter.getY() >= bottomrecs.get(x).getY())
return true;
for(int y = 3; y <= 7; y++)
if(helicopter.getY() <= toprecs.get(y).getY())
return true;
for(int z = 0; z <= 1; z++)
if(isInMidRange(z))
return true;
return false;
}
public boolean isInMidRange(int num)
{
Rectangle middlecheck = new Rectangle((int)middlerecs.get(num).getX(),(int)middlerecs.get(num).getY(),RECWIDTH,RECHEIGHT);
Rectangle coptercheck = new Rectangle((int)helicopter.getX(),(int)helicopter.getY(),70,48); //asteroid X and y bump
return middlecheck.intersects(coptercheck);
}
public void crash()
{
crashed = true;
if(distance > maxDistance)
{
maxDistance = distance;
save();
}
int reply = JOptionPane.showConfirmDialog(null, " RESTART ?", "GAME OVER", JOptionPane.YES_NO_OPTION);
if(reply == JOptionPane.YES_OPTION)
initiate();
else
System.exit(0);
initiate();
}
//moves the spaceship
public void updateCopter()
{
upCount += .10;
if(goingUp)
{
if(upCount < 3.5)
helicopter.setPosition(XPOS,(double)(helicopter.getY() - (.3 + upCount)));
else
helicopter.setPosition(XPOS,(double)(helicopter.getY() - (1.2 + upCount)));
helicopter.setImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rocketship.GIF");
}
else
{
if(upCount < 1)
helicopter.setPosition(XPOS,(double)(helicopter.getY() + upCount));
else
helicopter.setPosition(XPOS,(double)(helicopter.getY() + (1.2 + upCount)));
helicopter.setImage("C:\\Users/Travelmate/workspace/GAME/src/spaceSip/rocketship.GIF");
}
if(shoot())
crash();
}
//Called when the mouse exits the game window
public void mouseExited(MouseEvent e)
{
paused = true;
}
//Called when the mouse enters the game window
public void mouseEntered(MouseEvent e)
{
}
//Called when the mouse is released
public void mouseReleased(MouseEvent e)
{
goingUp = false;
upCount = -1;
if(paused)
paused = false;
}
//Called when the mouse is pressed
public void mousePressed(MouseEvent e)
{
if (!started)
started = true;
goingUp = true;
upCount = 0;
}
//Called when the mouse is released
public void mouseClicked(MouseEvent e)
{
}
}
package spaceSip;
import java.awt.Image;
import javax.swing.ImageIcon;
public class SpaceShipImage
{
private Image image; //The picture
private double x; //X position
private double y; //Y position
//Construct a new Moving Image with image, x position, and y position given
public SpaceShipImage(Image img, double xPos, double yPos)
{
image = img;
x = xPos;
y = yPos;
}
//Construct a new Moving Image with image (from file path), x position, and y position given
public SpaceShipImage(String path, double xPos, double yPos)
{
this(new ImageIcon(path).getImage(), xPos, yPos);
//easiest way to make an image from a file path in Swing
}
//They are set methods. I don't feel like commenting them.
public void setPosition(double xPos, double yPos)
{
x = xPos;
y = yPos;
}
public void setImage(String path)
{
image = new ImageIcon(path).getImage();
}
public void setY(double newY)
{
y = newY;
}
public void setX(double newX)
{
x = newX;
}
//Get methods which I'm also not commenting
public double getX()
{
return x;
}
public double getY()
{
return y;
}
public Image getImage()
{
return image;
}
}
package spaceSip;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Image;
import java.util.ArrayList;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
class SpaceShipPanel extends JPanel
{
private Image background;
private ArrayList<SpaceShipImage> middle;
private SpaceShipImage copter;
private ArrayList<SpaceShipImage> smoke;
//Constructs a new ImagePanel with the background image specified by the file path given
public SpaceShipPanel(String img)
{
this(new ImageIcon(img).getImage());
//The easiest way to make images from file paths in Swing
}
//Constructs a new ImagePanel with the background image given
public SpaceShipPanel(Image img)
{
background = img;
Dimension size = new Dimension(img.getWidth(null), img.getHeight(null));
//Get the size of the image
//Thoroughly make the size of the panel equal to the size of the image
//(Various layout managers will try to mess with the size of things to fit everything)
setPreferredSize(size);
setMinimumSize(size);
setMaximumSize(size);
setSize(size);
middle = new ArrayList<SpaceShipImage>();
smoke = new ArrayList<SpaceShipImage>();
}
//This is called whenever the computer decides to repaint the window
//It's a method in JPanel that I've overwritten to paint the background and foreground images
public void paintComponent(Graphics g)
{
//Paint the background with its upper left corner at the upper left corner of the panel
g.drawImage(background, 0, 0, null);
//Paint each image in the foreground where it should go
for(SpaceShipImage img : middle)
g.drawImage(img.getImage(), (int)(img.getX()), (int)(img.getY()), null);
for(SpaceShipImage img : smoke)
g.drawImage(img.getImage(), (int)(img.getX()), (int)(img.getY()), null);
if(copter != null)
g.drawImage(copter.getImage(), (int)(copter.getX()), (int)(copter.getY()), null);
drawStrings(g);
}
public void drawStrings(Graphics g)
{
g.setColor(Color.WHITE);
g.setFont(new Font("Arial",Font.BOLD,20));
g.drawString("Distance: " + SpaceShipMain.distance,30,440);
g.setFont(new Font("Arial",Font.BOLD,20));
if (SpaceShipMain.distance > SpaceShipMain.maxDistance)
g.drawString("Best: " + SpaceShipMain.distance,650,440);
else
g.drawString("Best: " + SpaceShipMain.maxDistance,650,440);
if(SpaceShipMain.paused)
{
g.setFont(new Font("Chiller",Font.BOLD,72));
g.drawString("Paused",325,290);
g.setFont(new Font("Chiller",Font.BOLD,30));
g.drawString("Click to unpause.",320,340);
}
}
//Replaces the list of foreground images with the one given, and repaints the panel
public void updateImages(ArrayList<SpaceShipImage> newMiddle,SpaceShipImage newCopter,ArrayList<SpaceShipImage> newSmoke)
{
copter = newCopter;
middle = newMiddle;
smoke = newSmoke;
repaint(); //This repaints stuff... you don't need to know how it works
}
}
You compare Strings with equals(value equality) not with ==(reference equality). For more information read this previous question How do I compare strings in Java?
As #AndrewThompson always advice don't use NullLayout
Java GUIs might have to work on a number of platforms, on different
screen resolutions & using different PLAFs. As such they are not
conducive to exact placement of components. To organize the
components for a robust GUI, instead use layout managers, or
combinations of
them1, along
with layout padding & borders for white
space2.
As you say that your gui is blocked, that may be cause some of your execution code takes too more time and it's executed in the same thread as gui stuff (The Event Dispatch Thread). As you have a while(true) that's block the gui so use a SwingTimer for execute repeatidly task or if that code that takes long time execute it in a background thread using a Swing Worker. Here you have a complete example. When you perform custom painting you should override paintComponent and in first line you have to call super.paintComponent(..) to follow correct chaining. Read more in Painting in AWT-Swing.
Another error i see is that you are adding components after calling setVisible(true) without calling revalidate() repaint(). So i recommend to first add components to container then call setVisible(true) at final step.
I am making a JFrame holding several images that refresh using repaint(). The problem, however, was that the more images I added (or as the area that was being rendered increased) the framerate drastically decreased.
I was initially attempting to reduce the lag that Swing's unpredictable Timer experiences, but was unsuccessful. This time, I tried to call
repaint()
every 10 milliseconds based on system time. (To bypass the timer, desktop.screenPaint.drawWindow(); is called instead of repaint())
while(true)
{
long starttime = System.currentTimeMillis();
while(System.currentTimeMillis()-starttime < 10)
{
}
desktop.screenPaint.drawWindow();
desktop2.screenPaint.drawWindow();
}
Each "desktop" is just one of the draggable windows that you see if you run the code below. I noticed that when only "desktop" is added to "frame," there is no flickering. However, when "desktop2" is also added, flickering does not go away until the time until each refresh is set to 20 or more milliseconds. It is extremely strange, because when I was still using the timer, even thought the wait was set to 10 milliseconds, the framerate would lower to a frame every 20 milliseconds! I tested a little and noticed a trend: you will get flickering until the wait time to the amount of time that the 10 millisecond timer lagged behind. My question: Why is this happening? And is there any way to prevent the flickering, other than going back to the timer?
import javax.swing.JFrame;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.SwingUtilities.*;
import static java.awt.GraphicsDevice.WindowTranslucency.*;
import java.io.File;
import java.io.IOException;
public class Display extends JPanel
{
public static int width, height;
public static JFrame frame = new JFrame("");
private static int rh = 10;
public static Display desktop = new Display();
public static Display desktop2 = new Display();
public static void main(String[] args)
{
Dimension screen = new Dimension();
screen = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
width = (int)screen.getWidth();
height = (int)screen.getHeight();
frame.setLayout(null);
frame.setLocation(0, 0);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(null);
desktop.setBounds(0, 0, 620, 500+rh);
desktop2.setBounds(1000, 200, 620, 500+rh);
frame.add(desktop);
frame.add(desktop2);
frame.setUndecorated(true);
frame.setSize(width, height);
frame.setVisible(true);
while(true)
{
long starttime = System.currentTimeMillis();
while(System.currentTimeMillis()-starttime < 10)
{
}
desktop.screenPaint.drawWindow();
//desktop2.screenPaint.drawWindow();
}
}
private BufferedImage image;
private Graphics2D g;
public Listener screenPaint = new Listener();
private Display identify;
public Display()
{
identify = this;
image = new BufferedImage(620, 500+rh, BufferedImage.TYPE_INT_RGB);
g = (Graphics2D)image.getGraphics();
Timer timer = new Timer(1, screenPaint);
timer.start();
addMouseListener(new mMouse());
addMouseWheelListener(new wWheel());
setFocusable(true);
}
private BufferedImage toCompatibleImage(BufferedImage image)
{
GraphicsConfiguration gfx_config = GraphicsEnvironment.
getLocalGraphicsEnvironment().getDefaultScreenDevice().
getDefaultConfiguration();
if (image.getColorModel().equals(gfx_config.getColorModel()))
return image;
BufferedImage new_image = gfx_config.createCompatibleImage(
image.getWidth(), image.getHeight(), image.getTransparency());
}
public void paint(Graphics view)
{
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
view.drawImage(toCompatibleImage(image), 0, 0, 620, 500+rh, null);
view.dispose();
}
private class Listener implements ActionListener
{
int y = 0;
int wy = 0;
int b = 500;
int c = 1500;
int iy = (int)(wy/(c/(double)b));
int a = -1;
int i = -1;
int j = -1;
boolean d = false;
boolean u = false;
int f = 0;
public void moveY(int sy)
{
f += sy;
}
public void actionPerformed(ActionEvent e)
{
//drawWindow();
}
public void drawWindow()
{
int lx = (int)(identify.getLocation().getX());
int ly = (int)(identify.getLocation().getY());
g.setColor(Color.white);
g.fillRect(0, 0, 620, 500+rh);
g.drawImage(new ImageIcon("image.png").getImage(), 0, wy+rh, 610, c, null);
if(c > b)
{
if(d || Mouse.withinRect(610+lx, (int)(-wy/(c/(double)b))+rh+ly, 10, (int)Math.ceil(Math.pow(b, 2)/(double)c)))
{
if(Mouse.pressLeft())
{
if(!d)d = true;
if(a == -1)a = Mouse.y()-(int)(-wy/(c/(double)b));
y = (int)((Mouse.y()-a)*(c/(double)b));
f = y;
g.setColor(Color.black);
}
else
{
if(d)d = false;
if(a != -1)a = -1;
g.setColor(new Color(60, 60, 60));
}
}
else
{
g.setColor(Color.gray);
if(a != -1)a = -1;
}
if(y == f){}
else if(y < f)
{
y += (int)((f-y)*0.1);
if(y < f)y++;
}
else
{
y -= (int)((y-f)*0.1);
if(y > f)y--;
}
if(y < 0)
{
y = 0;
f = 0;
}
else if(y > c-b)
{
y = c-b;
f = y;
}
wy = -y;
if(u || Mouse.withinRect(lx, ly, 620, 10))
{
if(Mouse.pressLeft())
{
if(!u)u = true;
if(i == -1)i = Mouse.x()-lx;
if(j == -1)j = Mouse.y()-ly;
identify.setLocation(Mouse.x()-i, Mouse.y()-j);
}
else
{
if(u)u = false;
if(i != -1)i = -1;
if(j != -1)j = -1;
}
}
else
{
if(u)u = false;
if(i != -1)i = -1;
if(j != -1)j = -1;
}
int scrollBarLength = (int)Math.ceil(Math.pow(b, 2)/(double)c);
g.fillRect(610, (int)(-wy/(c/(double)b))+rh, 10, scrollBarLength);
}
else
{
g.setColor(new Color(200, 200, 200));
g.fillRect(610, rh, 10, b);
}
g.setColor(new Color(50, 50, 50));
g.fillRect(0, 0, 620, rh);
if(identify == desktop)
repaint();
else if(false)
{}
}
}
}
public static boolean LMPress, LMRelease = false;
public static boolean LMRight, LMLeft = false;
private class mMouse extends MouseAdapter
{
public void mousePressed(MouseEvent e)
{
LMPress = true; LMRelease = false;
if(SwingUtilities.isRightMouseButton(e))
{
LMRight = true;
LMLeft = false;
}
else if(SwingUtilities.isLeftMouseButton(e))
{
LMLeft = true;
LMRight = false;
}
}
public void mouseReleased(MouseEvent e)
{
LMRelease = true; LMPress = false;
if(SwingUtilities.isRightMouseButton(e))
{
LMRight = true;
LMLeft = false;
}
else if(SwingUtilities.isLeftMouseButton(e))
{
LMLeft = true;
LMRight = false;
}
}
}
private class wWheel implements MouseWheelListener
{
public void mouseWheelMoved(MouseWheelEvent e)
{
int notches = e.getWheelRotation();
if (e.getScrollType() == MouseWheelEvent.WHEEL_UNIT_SCROLL) {}
e.getScrollAmount();
screenPaint.moveY(e.getUnitsToScroll()*60); //desired pixel jump: 120
}
}
}
Mouse class:
import java.awt.*;
import java.awt.event.*;
public class Mouse {
public static int x() {
PointerInfo a = MouseInfo.getPointerInfo();
Point b = a.getLocation();
return (int) b.getX();
}
public static int y() {
PointerInfo a = MouseInfo.getPointerInfo();
Point b = a.getLocation();
return (int) b.getY();
}
public static boolean withinRect(int x, int y, int w, int h) {
if (x() >= x && x() < x + w && y() >= y && y() < y + h) return true;
else return false;
}
public static boolean press() {
return Display.LMPress;
}
public static boolean release() {
return Display.LMRelease;
}
public static boolean pressLeft() {
if (Display.LMPress && Display.LMLeft)
return true;
else return false;
}
public static boolean releaseLeft() {
if (Display.LMRelease && Display.LMLeft)
return true;
else return false;
}
public static boolean pressRight() {
if (Display.LMPress && Display.LMRight)
return true;
else return false;
}
public static boolean releaseRight() {
if (Display.LMRelease && Display.LMRight)
return true;
else return false;
}
}
Updating the view at 1 kHz is unrealistic; instead, consider the alternatives cited here. See this AnimationTest for an example of self-timing to determine your animation budget.
Addendum: The while(true) loop at the top is running at 100 Hz.
The available resolution of System.currentTimeMillis() may vary by platform.
Addendum: I am reopening this question because I was not able to fix it. Any more help?
Absent a Minimal, Complete, Tested and Readable Example, it's hard to say. You appear to be overriding paint(); was noted in Painting in AWT and Swing: The Paint Methods, "Swing programs should override paintComponent()." Moreover, you need to invoke super.paintComponent(), as shown here, to avoid visual artifacts.
basically i have been following a Java tutorial to make a basic maze game where i generate a random maze which is saved to a file then i print it out using Jpanel however i keep getting this error when i compile.
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at maze.Map.getMap(Map.java:43)
at maze.Board.paint(Board.java:40)
However i am not sure why, i believe it is something to do with my Y integer but if i set it to 0 it causes my program to print out wrong(just prints the same column instead of changing rows).
I need the Y value in Map.java:43 to increase like my x value does however it provides me with the Exception error.
Code:
Map Class
package maze;
import java.awt.Image;
import java.io.File;
import java.util.*;
import javax.swing.ImageIcon;
public class Map {
private Scanner m;
private Image wall, ground;
//number of columns
private String Map[] = new String[20];
public Map() {
//sets ground to a texture
ImageIcon img = new ImageIcon("C:\\MazeGraphics\\ground.png");
ground = img.getImage();
//sets wall texture
img = new ImageIcon("C:\\MazeGraphics\\wall.png");
wall = img.getImage();
openFile();
readFile();
closeFile();
}
public Image getGround() {
// gives grass texture for screen
return ground;
}
public Image getWall() {
// gives wall texture for screen
return wall;
}
public String getMap(int x, int y) {
//compares string to find graphic to use
String index= Map[y].substring(x, x+1);
return index;
}
public void openFile() {
try {
m = new Scanner(new File("C:\\MazeGraphics\\Maze.txt"));
} catch (Exception e) {
System.out.println("Error Loading Map");
}
}
public void readFile() {
for(int i = 0; i < 20; i++)
{
while(m.hasNext()){
Map[i] = m.next();
}
}
}
public void closeFile() {
m.close();
}
}
Board Class:
package maze;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Board extends JPanel implements ActionListener {
private Timer timer;
private Map m;
private Player p;
public Board()
{
MazeGeneration maz=new MazeGeneration();
//runs Map class
m = new Map();
p = new Player();
//listens for key presses
addKeyListener(new Al());
//knows to add key listener to the frame
setFocusable(true);
timer = new Timer(25, this);
timer.start();
}
public void actionPerformed(ActionEvent e) {
repaint();
}
public void paint(Graphics g) {
super.paint(g);
//paints the board row by row
for (int y = 0; y < 20; y++)
{
for (int x = 0; x < 20; x++)
{
//places graphic depending on the letter.
if (m.getMap(x, y).equals("g"))
{
g.drawImage(m.getGround(), y * 32, x * 32, null);
}
if (m.getMap(x, y).equals("w"))
{
g.drawImage(m.getWall(), y * 32,x * 32, null);
}
}
}
g.drawImage(p.getPlayer(), p.gettileX() * 32, p.gettileY() * 32, null);
}
public class Al extends KeyAdapter {
//moving the player
public void keyPressed(KeyEvent e, char maz[][], int r, int c) {
int keycode = e.getKeyCode();
if (keycode == KeyEvent.VK_W) {
//if not a wall can move
if (!m.getMap(p.gettileX(), p.gettileY() - 1).equals("w")) {
p.move(0, -1);
}
}
if (keycode == KeyEvent.VK_S) {
if (!m.getMap(p.gettileX(), p.gettileY() + 1).equals("w")) {
p.move(0, 1);
}
}
if (keycode == KeyEvent.VK_A) {
if (!m.getMap(p.gettileX() - 1, p.gettileY()).equals("w")) {
p.move(-1, 0);
}
}
if (keycode == KeyEvent.VK_D) {
if (!m.getMap(p.gettileX() + 1, p.gettileY() ).equals("w")) {
p.move(1, 0);
}
}
}
}
}
The issue is in this code: In your readFile() method, your issue arises during reading your file:
for(int i = 0; i < 20; i++)
{
while(m.hasNext()){
Map[i] = m.next();
}
}
You are assigning the value only to the 0'th index. To explain, for the first for loop, the index i is at zero. The inner loop "iterates" through the Scanner m until there is no element next. Therefore, Map[0] contains the last element on the file.
Your solution is as follows:
int i = 0;
while (m.hasNext()) {
Map[i++] = m.next();
}
I hope this helps.
I am almost done with my first little java game for my final project. It is a sidescroller where you have to shoot/avoid asteroids. My last problem is figuring out how to make my array of asteroids collide with the player's lasers. Here's what I have so far, there's an "AWT-EventQueue-0" java.lang.NullPointerException" on line 137, that I can't deal with. Any help is appreciated.
Edit: I added in my other classes, I realize it would be hard to judge the functionality of my code if I didn't show you where it came from.
package ShooterGame;
import java.applet.Applet;
import java.applet.AudioClip;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.util.Random;
import javax.swing.*;
public class Board extends JPanel implements ActionListener
{
Enemy[] baddies = new Enemy[10000];
Player p;
Image img;
int y;
Timer time;
boolean lost = false;
static Font font = new Font("SanSerif", Font.BOLD, 24);
public AudioClip theme, bang, laser;
static ArrayList<Enemy> enemies;
public static int score = 0;
public static int lives = 5;
public Board()
{
p = new Player();
addKeyListener(new ActionListener());
setFocusable(true);
ImageIcon i = new ImageIcon("images/background.png");
img = i.getImage();
time = new Timer(5, this);
time.start();
for(int j = 0; j < baddies.length; j++)
{
Random ran = new Random();
y = ran.nextInt(365)+1;
baddies[j]= new Enemy((100*j + 700), y, "images/asteroid.gif");
}
theme = Applet.newAudioClip(getClass().getResource("theme.mid"));
theme.play();
bang = Applet.newAudioClip(getClass().getResource("bang.wav"));
}
public void actionPerformed(ActionEvent e)
{
checkCollisions();
ArrayList<?> bullets = Player.getBullets();
for(int i = 0; i < bullets.size(); i++)
{
Bullet b = (Bullet)bullets.get(i);
if(b.isVisible() == true)
{
b.move();
}
else
{
bullets.remove(i);
}
}
p.move();
for(int i = 0; i < baddies.length; i++)
{
if(p.x > 400)
{
baddies[i].move(p.getdx());
}
}
repaint();
}
public void paint(Graphics g)
{
super.paint(g);
Graphics2D g2d = (Graphics2D) g;
if(lost)
{
g2d.drawString("You Lose!", 300, 300);
}
if((p.getX() - 590) % 2400 == 0 || (p.getX() - 590) % 2400 == 1)
{
p.nx = 0;
}
if((p.getX() - 1790) % 2400 == 0 ||(p.getX() - 1790) % 2400 == 1)
{
p.nx2 = 0;
}
g2d.drawImage(img, 685-p.nx2, 0, null);
if(p.getX() >= 590)
{
g2d.drawImage(img, 685-p.nx, 0, null);
}
g2d.drawImage(p.getImage(), p.edge, p.getY(), null);
ArrayList<?> bullets = Player.getBullets();
for(int i = 0; i < bullets.size(); i++)
{
Bullet b = (Bullet)bullets.get(i);
g2d.drawImage(b.getImg(), b.getX(), b.getY(), null);
}
for(int i = 0; i < baddies.length; i++)
{
if(baddies[i].isAlive == true)
{
g2d.drawImage(baddies[i].getImg(), baddies[i].getX(), baddies[i].getY(), null);
}
}
g2d.setColor(Color.white);
g2d.drawString("Score: " + score, 0, 320);
g2d.drawString("Lives: " + lives, 80, 320);
}
public void checkCollisions()
{
Rectangle[] rect = new Rectangle[baddies.length];
for(int i = 0; i < baddies.length; i++)
{
Enemy e = (Enemy)baddies[i];
rect[i] = e.getBounds();
}
ArrayList<?> bullets = Player.getBullets();
for (int i = 0; i < bullets.size(); i++)
{
Bullet b = (Bullet) bullets.get(i);
Rectangle b1 = b.getBounds();
if (rect[i].intersects(b1) && baddies[i].isAlive())
{
score++;
baddies[i].isAlive = false;
baddies[i].isVisible = false;
bang.play();
}
Rectangle h = p.getBounds();
if (h.intersects(rect[i]))
{
if(baddies[i].isAlive() == true)
{
lives--;
if(lives < 0)
{
lost = true;
theme.stop();
System.exit(1);
}
}
}
}
}
private class ActionListener extends KeyAdapter
{
public void keyReleased(KeyEvent e)
{
p.keyReleased(e);
}
public void keyPressed(KeyEvent e)
{
p.keyPressed(e);
}
}
}
Enemy
package ShooterGame;
import java.awt.*;
import javax.swing.ImageIcon;
public class Enemy
{
int x, y;
Image img;
boolean isAlive = true;
boolean isVisible = true;
public Enemy(int startX, int startY, String location)
{
x = startX;
y = startY;
ImageIcon l = new ImageIcon(location);
img = l.getImage();
}
public Rectangle getBounds()
{
return new Rectangle(x, y, 60, 60);
}
public int getX()
{
return x;
}
public int getY()
{
return y;
}
public boolean isAlive()
{
return isAlive;
}
public boolean isVisible()
{
return isVisible;
}
public Image getImg()
{
return img;
}
public void move(int dx)
{
x = x - dx;
}
}
Bullet
package ShooterGame;
import java.applet.Applet;
import java.awt.*;
import javax.swing.ImageIcon;
import java.applet.AudioClip;
public class Bullet
{
int x, y;
Image img;
boolean visible;
public Bullet(int startX, int startY)
{
x = startX;
y = startY;
ImageIcon newBullet = new ImageIcon("images/bullet.gif");
img = newBullet.getImage();
visible = true;
}
public Rectangle getBounds()
{
return new Rectangle(x, y, 9, 5);
}
public int getX()
{
return x;
}
public int getY()
{
return y;
}
public Image getImg()
{
return img;
}
public boolean isVisible()
{
return visible;
}
public void move()
{
x = x + 2;
if(x > 700)
{
visible = false;
}
}
public void setVisible(boolean isVisible)
{
visible = isVisible;
}
}
Player
package ShooterGame;
import java.applet.Applet;
import java.applet.AudioClip;
import java.awt.*;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import javax.swing.ImageIcon;
public class Player
{
int x, dx, y, dy, nx2, nx, edge, ceiling;
Image player;
ImageIcon ib = new ImageIcon("images/player1back.gif");
ImageIcon i = new ImageIcon("images/playerstill.gif");
ImageIcon f = new ImageIcon("images/playerforward.gif");
ImageIcon up = new ImageIcon("images/playerup.gif");
ImageIcon down = new ImageIcon("images/playerdown.gif");
public AudioClip laser;
static ArrayList<Bullet> bullets;
public Player()
{laser = Applet.newAudioClip(getClass().getResource("laser.wav"));
player = ib.getImage();
x = 75;
nx = 0;
nx2 = 685;
y = 172;
edge = 150;
ceiling = 0;
bullets = new ArrayList<Bullet>();
}
public static ArrayList<Bullet> getBullets()
{
return bullets;
}
public void fire()
{
Bullet z = new Bullet((edge + 60), (y+17));
bullets.add(z);
}
public Rectangle getBounds()
{
return new Rectangle(edge, y, 43, 39);
}
public void move()
{
y = y + dy;
if(y < ceiling)
{
y = ceiling;
}
if(y > 290)
{
y = 290;
}
if(dx != -1)
{
if(edge + dx <= 151)
{
edge = edge + dx;
}
else
{
x = x + dx;
nx2 = nx2 + dx;
nx = nx + dx;
}
}
else
{
if(edge + dx > 0)
{
edge = edge + dx;
}
}
}
public int getX()
{
return x;
}
public int getdx()
{
return dx;
}
public int getY()
{
return y;
}
public Image getImage()
{
return player;
}
public void keyPressed(KeyEvent e)
{
int key = e.getKeyCode();
if(key == KeyEvent.VK_RIGHT)
{
dx = 2;
player = f.getImage();
}
if(key == KeyEvent.VK_UP)
{
dy = -1;
player = up.getImage();
}
if(key == KeyEvent.VK_DOWN)
{
dy = 1;
player = down.getImage();
}
if(key == KeyEvent.VK_SPACE)
{
fire();
laser.play();
}
}
public void keyReleased(KeyEvent e)
{
int key = e.getKeyCode();
if(key == KeyEvent.VK_RIGHT)
{
dx = 1;
player = ib.getImage();
}
if(key == KeyEvent.VK_UP)
{
dy = 0;
player = ib.getImage();
}
if(key == KeyEvent.VK_DOWN)
{
dy = 0;
player = ib.getImage();
}
}
}
Frame
package ShooterGame;
import javax.swing.*;
public class Frame
{
public AudioClip theme;
public Frame()
{
JFrame frame = new JFrame();
frame.add(new Board());
frame.setTitle("SideShooter");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(700,365);
frame.setVisible(true);
frame.setLocationRelativeTo(null);
}
public static void main(String[] args)
{
new Frame();
}
}
Ok, so the problem is the line mentioned in the other answer, but I believe it is that all the enemies may not be initialised before it checks collisions. Because you are making 10000 of them to start with, I think your action performed method may be checking collisions before they have all be created.
One thing to try could be to bring down the amount of enemies you have and see if it still keeps happening, try 100 or 1000, but this still won't fix the issue.
You really want to be change your game to run in it's own loop though, at the moment you are only checking collisions when the player performs an action. so if the player stops moving, no collision detection...
I would suggest that you find a book called 'Killer Game Programming in Java', there are free ebook version, and just read the first 2 chapters about making a game loop. The book is a bit old, but the basics of the loop are very good.
This question here also contains a very simple loop, and some suggestions in the comments about how to make it better.
The error is on the line
rect[i] = e.getBounds();
Are you not initializing the bounds of your Enemy class correctly? Alternatively, the Enemy you pulled out of the array could be null.