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Typing game: choosing two words

I'm creating a game like zType
and I have a problem in validating the input. As you can see in the picture below it select two words. How can I fix this problem, please help.
This is My Game class
import java.awt.Canvas;
import java.awt.event.KeyListener;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.LinkedList;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
public class Game extends Canvas implements Runnable, KeyListener
{
public static final int WIDTH = 640;
public static final int HEIGHT = 680;
public final String TITLE = "Game";
private boolean running = false;
private Thread thread;
private BufferedImage spriteSheet = null;
private BufferedImage background = null;
public int level = 1;
public int fps = 0;
public int score = 0;
private int enemy_count = 15;
private int enemy_killed = 0;
private int enemy_notkilled = 0;
private boolean target = false;
public String t = "";
private Controller c;
private Textures tex;
private LinkedList<Enemy> e = new LinkedList<Enemy>();
private Enemy enemy;
public void init()
{
requestFocus();
try
{
spriteSheet = ImageIO.read(getClass().getResource("/sprite_sheet.png"));
background = ImageIO.read(getClass().getResource("/background.png"));
}
catch(IOException e)
{
e.printStackTrace();
}
tex = new Textures(this);
c = new Controller(tex, this);
addKeyListener(this);
c.createEnemy(enemy_count);
e = c.getEnemy();
}
private synchronized void start()
{
if(running)
return;
running = true;
thread = new Thread(this);
thread.start();
}
private synchronized void stop()
{
if(!running)
return;
running = false;
try
{
thread.join();
}
catch(InterruptedException e)
{
e.printStackTrace();
}
System.exit(1);
}
public void run()
{
init();
long lastTime = System.nanoTime();
final double amountOfTicks= 60.0;
double ns = 1000000000 / amountOfTicks;
double delta = 0;
int frames = 0;
long timer = System.currentTimeMillis();
while(running)
{
long now = System.nanoTime();
delta += (now - lastTime) / ns;
lastTime = now;
if(delta >= 1)
{
update();
delta--;
}
render();
frames++;
if(System.currentTimeMillis() - timer > 1000)
{
timer += 1000;
fps = frames;
frames = 0;
}
}
stop();
}
private void update()
{
c.update();
if(enemy_killed + enemy_notkilled >= enemy_count)
{
e.clear();
t = "";
level++;
enemy_killed = 0;
enemy_notkilled = 0;
c.createEnemy(enemy_count);
}
}
private void render()
{
BufferStrategy bs = this.getBufferStrategy();
if(bs == null)
{
createBufferStrategy(3);
return;
}
Graphics g = bs.getDrawGraphics();
g.drawImage(background, 0, 0, null);
c.render(g);
g.dispose();
bs.show();
}
public void keyPressed(KeyEvent ek)
{
int key = ek.getKeyCode();
char character = Character.toLowerCase(ek.getKeyChar());
boolean result = isValid(key);
if(result && !target)
{
for(int i = 0; i < e.size(); i++)
if(e.get(i).getFirstLetter() == character && e.get(i).getOnScreen())
{
enemy = e.get(i);
t = enemy.getText();
if(enemy.getCurrentIndex() == 0)
enemy.addCurrentIndex();
target = true;
System.out.println("---"+enemy.text);
break;
}
}
else if(result && t.charAt(enemy.getCurrentIndex()) == character)
enemy.addCurrentIndex();
}
public void keyReleased(KeyEvent ek){ }
public void keyTyped(KeyEvent ek){ }
public static void main(String[] args)
{
Game game = new Game();
game.setPreferredSize(new Dimension(WIDTH, HEIGHT));
game.setMaximumSize(new Dimension(WIDTH, HEIGHT));
game.setMinimumSize(new Dimension(WIDTH, HEIGHT));
JFrame frame = new JFrame(game.TITLE);
frame.add(game);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
game.start();
}
public boolean isValid(int key)
{
return key >= 65 && key <= 90 ? true : false;
}
public BufferedImage getSpriteSheet()
{
return spriteSheet;
}
public int getEnemy_count()
{
return enemy_count;
}
public void setEnemy_count(int enemy_count)
{
this.enemy_count = enemy_count;
}
public int getEnemy_killed()
{
return enemy_killed;
}
public void setEnemy_killed(int enemy_killed)
{
this.enemy_killed = enemy_killed;
}
public int getEnemy_notkilled()
{
return enemy_notkilled;
}
public void setEnemy_notkilled(int enemy_notkilled)
{
this.enemy_notkilled = enemy_notkilled;
}
public void addScore(int k)
{
score += k;
}
public void falseTarget()
{
target = false;
}
public String getT()
{
return t;
}
public void setT(String k)
{
t = k;
}
}
This is my Enemy Class
import java.awt.*;
import java.awt.font.TextAttribute;
import java.text.AttributedString;
public class Enemy
{
private double x ,y;
public String text;
private char firstLetter;
private AttributedString as;
private Controller c;
private Textures tex;
private Game game;
private int currentIndex = 0;
private int textLength = 0;
private double speed = 0.0;
private int stringWidth = 0;
private boolean onScreen = false;
public Enemy(double x, double y, double speed, Textures tex, Controller c, Game game, String text, int stringWidth)
{
this.x = x;
this.y = y;
this.tex = tex;
this.text = text;
this.game = game;
this.c = c;
this.speed = speed;
firstLetter = this.text.charAt(0);
textLength = this.text.length();
this.stringWidth = stringWidth;
}
public void update()
{
y += speed;
if(y >= 0)
onScreen = true;
if(currentIndex >= textLength)
{
game.addScore(5);
game.setT("");
c.removeEnemy(this);
game.setEnemy_killed(game.getEnemy_killed() + 1);
game.falseTarget();
}
if(y >= Game.HEIGHT - 50)
{
//game.decreaseHealth();
game.setT("");
c.removeEnemy(this);
game.setEnemy_notkilled(game.getEnemy_notkilled() + 1);
game.falseTarget();
game.t ="";
}
}
public void render(Graphics g)
{
g.drawImage(tex.enemy, (int)x, (int)y, null);
as = new AttributedString(text);
if(currentIndex >= 1)
as.addAttribute(TextAttribute.FOREGROUND, Color.WHITE, 0, currentIndex);
as.addAttribute(TextAttribute.FONT, new Font("Consolas", Font.BOLD, 12), 0, text.length());
g.drawString(as.getIterator(), (int)x + getAdd(stringWidth), (int)y + 13);
}
public double getX()
{
return x;
}
public double getY()
{
return y;
}
public String getText()
{
return text;
}
public char getFirstLetter()
{
return firstLetter;
}
public void addCurrentIndex()
{
currentIndex++;
}
public int getCurrentIndex()
{
return currentIndex;
}
public int getTextLength()
{
return textLength;
}
public int getAdd(int width)
{
return (96 / 2) - (width / 2);
}
public boolean getOnScreen()
{
return onScreen;
}
}

The problem is that you're calling falseTarget() whenever an enemy moves out of the screen. In your example, you assigned target = true when you pressed the 'o' (for the enemy named "owe"), but then a different enemy (maybe "jet", maybe an enemy that is no longer visible) finished "dropping" out of the screen (y >= Game.HEIGHT - 50), so you called falseTarget() - and thus, when you pressed 'i' you started a new enemy ("ice").
What you want to do is call falseTarget() in this case only if the enemy that dropped out of the screen is the one that's currently being targeted:
if(y >= Game.HEIGHT - 50)
{
//game.decreaseHealth();
//game.setT(""); // <-- Commented this line out
c.removeEnemy(this);
game.setEnemy_notkilled(game.getEnemy_notkilled() + 1);
if(game.getT().equals(text)) // <-- Added this if before calling falseTarget()
{ // and clearing the game's current enemy text
game.falseTarget();
game.t ="";
}
}

why wont my program paintComponent() if I set an ImageIcon and Image?

I've tried to find similar questions, but I think I have a unique situation here.
I am programming a game in java, my main class creates a frame which adds a component class which is an extension of JPanel. Basically, I draw these ovals and they move around and do different things, and I want to implement a method inside of one my classes which will use an image instead of an oval. However, anytime I try to create and image from a file, the program will not run the overridden "paintComponent(Graphics g)" method.
My main:
package mikeengine;
import javax.swing.JFrame;
public class MikeEngine {
static final int fx = 1300;
static final int fy = 800;
static final int px = 1292;
static final int py = 767;
static interactivePanel levelPanel;
public static void pause() {
try {
Thread.sleep(10); // wait 10ms
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
JFrame frame = new JFrame("MEngine");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(fx, fy);
frame.setResizable(false);
frame.setVisible(true);
levelPanel = new interactivePanel();
addship();
frame.getContentPane().add(levelPanel);
levelPanel.requestFocusInWindow();
while (true) {
pause();
levelPanel.move();
levelPanel.repaint();
}
}
static void addship() {
PlayerShip ship = new PlayerShip(100, 25, 25, px, 0, py, 0);
ship.setGraphic("C:/Users/asdf/Documents/NetBeansProjects/mikeEngine/src/mikeengine/res/right-arrow.jpg");
levelPanel.addObject(ship);
for (int i = 0; i < 5; i++) {
PlayerShip ship2 = new PlayerShip((int) (Math.random() * 1000) + 100, (int) (Math.random() * 1000) + 100, 25, px, px / 2, py, 0);
ship2.setMovement((int) (Math.random() * 10) / 5, (int) (Math.random() * 10) / 2);
levelPanel.addObject(ship2);
}
}
}
now, if I comment out the line:
ship.setGraphic("C:/Users/asdf/Documents/NetBeansProjects/mikeEngine/src/mikeengine/res/right-arrow.jpg");
everything renders perfectly.
I don't even paint the image that is going to be created. The image variable is just part of a class and it is currently just being created and doing nothing, so I don't understand how it affects the paintcomponentMethod(), if the paintComponent() isn't even told to try to paint the image ever.
The "PlayerShip" class extends the abstract "OnScreenObject" class (you really shouldn't need to see the code for PlayerShip, it only overrides one irrelevant method).
OnScreenObject looks like so:
package mikeengine;
import java.awt.Color;
import java.awt.Image;
import javax.swing.ImageIcon;
public abstract class OnScreenObject {
private ImageIcon graphic;
Image g;
protected int xmin;
protected int ymin;
protected int xsize;
protected int ysize;
protected int rise;
protected int run;
protected int containerYMax;
protected int containerYMin;
protected int containerXMax;
protected int containerXMin;
protected boolean visible;
protected boolean allowedOffscreen;
protected boolean isSelected;
protected Color color;
OnScreenObject(int x, int y, int sizeX, int sizeY, int cxMax, int cxMin, int cyMax, int cyMin) {
xmin = x;
ymin = y;
xsize = sizeX;
ysize = sizeY;
containerXMax = cxMax;
containerXMin = cxMin;
containerYMax = cyMax;
containerYMin = cyMin;
//
rise = 0;
run = 0;
visible = true;
allowedOffscreen = false;
isSelected = false;
}
public int getXMin() {
return xmin;
}
public int getYMin() {
return ymin;
}
public int getXMax() {
return xmin + xsize;
}
public int getYMax() {
return ymin + ysize;
}
public int getXSize() {
return xsize;
}
public int getYSize() {
return ysize;
}
public Color getColor() {
return color;
}
public boolean getAllowedOffscreen() {
return allowedOffscreen;
}
public boolean getVisible() {
return visible;
}
public int getRun() {
return run;
}
public ImageIcon getGraphic() {
return graphic;
}
public boolean isWithin(int x, int y) {
return x >= xmin && x <= getXMax() && y >= ymin && y <= getYMax();
}
public void setXMin(int x) {
xmin = x;
}
public void setYMin(int y) {
ymin = y;
}
public void setXSize(int x) {
xsize = x;
}
public void setYSize(int y) {
ysize = y;
}
public void setGraphic(String setto) {
try{
graphic = new ImageIcon("setto");
g=graphic.getImage();
System.out.println("tried");
} catch(Exception e){
System.out.println("caught:" + e);
}
}
public void setAllowedOffscreen(boolean allowed) {
allowedOffscreen = allowed;
}
public void setMovement(int riseM, int runM) {
rise = riseM * -1;//rise means to go up, and negative will move it up
run = runM;
}
public void nudge(boolean horizontal, int amount) {
if (horizontal) {
run += amount;
} else {
rise += amount;
}
}
public void setVisible(boolean vis) {
visible = vis;
}
public void setColor(Color c) {
color = c;
}
public boolean checkCollide(OnScreenObject other) {
if (other.getYMax() < getYMin()) { //if other object is above this
return false;
}
if (other.getYMin() > getYMax()) {//if other object is below this
return false;
}
if (other.getXMax() < getXMin()) {//if other is to the left
return false;
}
if (other.getXMin() > getXMax()) {//if other is to the right
return false;
}
return true;
}
public void move() {
if (!allowedOffscreen) {
checkEdge();
}
xmin += run;
ymin += rise;
}
protected abstract void checkEdge();
}
The interactivePanel class is the one that extends JPanel:
package mikeengine;
import java.awt.Color;
import java.awt.Graphics;
import java.util.ArrayList;
import javax.swing.JPanel;
public class interactivePanel extends JPanel {
ArrayList<OnScreenObject> objects;
IClick myClick;
Ipress myType;
PlayerShip currentShip;
interactivePanel() {
objects = new ArrayList<>();
myClick = new IClick();
myType = new Ipress();
this.addMouseListener(myClick);
this.addKeyListener(myType);
}
#Override
public void paintComponent(Graphics g) {
System.out.println("painting");
paintBackground(g);
paintObjects(g);
checkClick();
checkPress();
}
public void move() {
System.out.println("here2");
checkDeadShip();//also sets current ship
moveObjects();//also removes invisible
checkCollisions();
} // end method move
private void checkClick() {
if (!myClick.getClicked()) {
return;
}
for (int i = 0; i < objects.size(); i++) {
OnScreenObject current = objects.get(i);
if (current.isWithin(myClick.getX(), myClick.getY())) {
System.out.println("CLICKED");
}
}
}
private void paintBackground(Graphics g) {
g.setColor(Color.black);
g.fillRect(0, 0, getWidth(), getHeight());
}
private void paintObjects(Graphics g) {
for (int i = 0; i < objects.size(); i++) {
OnScreenObject current = objects.get(i);
g.setColor(current.getColor());
g.fillOval(current.getXMin(), current.getYMin(), current.getXSize(), current.getYSize());
}
}
public void addObject(OnScreenObject toAdd) {
objects.add(toAdd);
}
private void checkPress() {
if (myType.getDown()) {
objects.get(0).nudge(false, 3);
}
if (myType.getUp()) {
objects.get(0).nudge(false, -3);
}
if (myType.getLeft()) {
objects.get(0).nudge(true, -3);
}
if (myType.getRight()) {
objects.get(0).nudge(true, 3);
}
if (myType.getSpace()) {
fire();
}
}
private void fire() {
OnScreenObject shotBullet = new Bullet(currentShip.getXMax(), ((currentShip.getYMax() - currentShip.getYMin()) / 2) + currentShip.getYMin(), 5, getWidth(), 0, getHeight(), 0);
int shipBonus = 0;
if (currentShip.getRun() > 0) {
shipBonus = currentShip.getRun();
}
shotBullet.setMovement(0, shipBonus + 5);
addObject(shotBullet);
}
private void checkCollisions() {
for (int i = 0; i < objects.size() - 1; i++) {
for (int j = 0; j < objects.size(); j++) {
if (j != i) {
OnScreenObject current = objects.get(i);
OnScreenObject next = objects.get(j);
if (current.checkCollide(next)) {
objects.remove(i);
if (i < j) {
objects.remove(j - 1);
} else {
objects.remove(j);
}
}
}
}
}
}
private void checkDeadShip() {
if (objects.size() > 0) {
try {
currentShip = (PlayerShip) objects.get(0);
} catch (Exception e) {
System.out.println("GAME OVER!");
}
}
}
private void moveObjects() {
for (int i = 0; i < objects.size(); i++) {
OnScreenObject current = objects.get(i);
current.move();
if (!current.getVisible()) {
objects.remove(i);
}
}
}
}
if I do not have that line commented out, the
System.out.println("painting"); inside of my public void paintComponent(Graphics g) is never run, which is why I assume that paintComponent isn't running.
(I cant post images since I don't have 10 rep, but its just a JFrame with the beige empty panel look when it is not commented out).

EDIT:
In your setGraphic() method, replace the line
graphic = new ImageIcon("setto");
with this:
graphic = new ImageIcon(this.getClass()
.getResource(setto));

how to notify multithread event on swing game

I am supposed to make a little game simulation. in this game there are three button . when user click start tank and car will close each other in 90 degrees when user click shut button tank will throw bullet to car.
i made and a simulation for this. tank throw bullet to car but when bullet crash car i couldn't this. i just need increase score of how many times tank hit car.
here is the source code
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JPanel;
public class Vehicle extends Thread {
private JPanel box;
private int XSIZE;
private int YSIZE;
private int time;
private int x;
private int y;
private int dx = 5;
private int dy = 5;
private int dim;
public Vehicle(JPanel b, int i) {
box = b;
this.dim = i;
if (i == 0) {
x = 0;
y = 100;
time = 1000;
XSIZE = 9;
YSIZE = 20;
} else {
time = 200;
y = box.getSize().height;
x = box.getSize().width / 2;
XSIZE = 6;
YSIZE = 10;
}
}
public void draw() {
Graphics g = box.getGraphics();
g.fillOval(x, y, XSIZE, YSIZE);
g.dispose();
}
public void moveHorizontal() {
if (!box.isVisible())
return;
Graphics g = box.getGraphics();
g.setColor(Color.BLUE);
g.setXORMode(box.getBackground());
g.fillOval(x, y, XSIZE, YSIZE);
x += dx;
Dimension d = box.getSize();
if (x < 0) {
x = 0;
dx = -dx;
}
if (x + XSIZE >= d.width) {
x = d.width - XSIZE;
dx = -dx;
}
g.fillOval(x, y, XSIZE, YSIZE);
g.dispose();
}
public JPanel getBox() {
return box;
}
public void setBox(JPanel box) {
this.box = box;
}
public void moveVertical() {
if (!box.isVisible())
return;
Graphics g = box.getGraphics();
g.setXORMode(box.getBackground());
g.fillOval(x, y, XSIZE, YSIZE);
y += dy;
Dimension d = box.getSize();
if (y < 0) {
y = 0;
dy = -dy;
}
if (y + YSIZE >= d.height) {
y = d.height - YSIZE;
dy = -dy;
}
g.fillOval(x, y, XSIZE, YSIZE);
g.dispose();
}
public void move(int i) {
if (i == 0) {
moveHorizontal();
} else {
moveVertical();
}
}
public int getYSIZE() {
return YSIZE;
}
public void setYSIZE(int ySIZE) {
YSIZE = ySIZE;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public int getXSIZE() {
return XSIZE;
}
public void setXSIZE(int xSIZE) {
XSIZE = xSIZE;
}
public void setY(int y) {
this.y = y;
}
public void run() {
try {
draw();
for (;;) {
move(dim);
sleep(time);
}
} catch (InterruptedException e) {
}
}
}
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JPanel;
public class Bullet extends Thread {
private JPanel box;
private int XSIZE = 3;
public int getXSIZE() {
return XSIZE;
}
public void setXSIZE(int xSIZE) {
XSIZE = xSIZE;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
private int YSIZE = 1;
private int x;
private int y;
private int dx = 3;
public Bullet(JPanel b, Vehicle tank, Vehicle car) {
box = b;
x = tank.getX() + tank.getXSIZE();
if (x >= tank.getBox().getSize().width / 2)
dx = -dx;
y = tank.getY() + tank.getYSIZE() / 2;
;
}
public void draw() {
Graphics g = box.getGraphics();
g.fillOval(x, y, XSIZE, YSIZE);
g.dispose();
}
public void move() {
if (!box.isVisible())
return;
Graphics g = box.getGraphics();
g.setColor(Color.RED);
g.setXORMode(box.getBackground());
g.fillOval(x, y, XSIZE, YSIZE);
x += dx;
Dimension d = box.getSize();
if (x < 0) {
x = 0;
}
if (x + XSIZE >= d.width) {
x = d.width - XSIZE;
}
g.fillOval(x, y, XSIZE, YSIZE);
g.dispose();
}
public void run() {
try {
draw();
for (;;) {
move();
sleep(20);
}
} catch (InterruptedException e) {
}
}
}
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JLabel;
#SuppressWarnings("serial")
public class Tank_Shut_Car_ThreadFrame extends JFrame {
private JPanel canvas;
private boolean isOn = false;
private Vehicle tank;
private Vehicle car;
private JLabel score;
public static int sc = 0;
public Tank_Shut_Car_ThreadFrame() {
setResizable(false);
setSize(600, 400);
setTitle("Tank Shut Car");
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
Container contentPane = getContentPane();
canvas = new JPanel();
contentPane.add(canvas, "Center");
canvas.setLayout(null);
score = new JLabel("0");
score.setBounds(527, 11, 36, 14);
canvas.add(score);
JLabel lblScore = new JLabel("score");
lblScore.setBounds(481, 11, 36, 14);
canvas.add(lblScore);
JPanel p = new JPanel();
addButton(p, "Start", new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (!isOn) {
tank = new Vehicle(canvas, 0);
tank.start();
car = new Vehicle(canvas, 1);
car.start();
isOn = true;
}
}
});
addButton(p, "Shut", new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (isOn) {
Bullet bullet = new Bullet(canvas, tank, car);
bullet.start();
score.setText("" + sc);
}
}
});
addButton(p, "Close", new ActionListener() {
public void actionPerformed(ActionEvent evt) {
canvas.setVisible(false);
System.exit(0);
}
});
contentPane.add(p, "South");
}
public void addButton(Container c, String title, ActionListener a) {
JButton button = new JButton(title);
c.add(button);
button.addActionListener(a);
}
}
import javax.swing.JFrame;
public class Test {
public static void main(String[] args) {
JFrame frame = new Tank_Shut_Car_ThreadFrame();
frame.setVisible(true);
}
}

Okay, so I had a play around with this (just for fun)
Now, this is far from a "proper" or "complete" game engine, but it provides a basic idea of how it might be possible to mix a core thread engine with UI components.
Rather then pasting the entire code, I've uploaded the source it to Tank.zip
But the basic engine looks like this...
public class GameEngine extends Thread {
public static final Object ASSET_LOCK = new Object();
private List<GameAsset> lstAssets;
private GameScreen screen;
public GameEngine(GameScreen screen) {
// Let the thread die when the JVM closes
setDaemon(true);
// Want to be below the UI thread (personal preference)
setPriority(NORM_PRIORITY - 1);
// A list of game assests
lstAssets = new ArrayList<GameAsset>(25);
// A reference to the screen
this.screen = screen;
// Add global key listener, this is simpler to the trying to attach a key listener
// to the screen.
Toolkit.getDefaultToolkit().addAWTEventListener(new EventHandler(), AWTEvent.KEY_EVENT_MASK);
}
public GameAsset[] getAssets() {
synchronized (ASSET_LOCK) {
return lstAssets.toArray(new GameAsset[lstAssets.size()]);
}
}
/*
* Allows for assets to be added
*/
public void addAsset(GameAsset asset) {
synchronized (ASSET_LOCK) {
lstAssets.add(asset);
}
}
#Override
public void run() {
while (true) {
try {
sleep(40);
} catch (InterruptedException ex) {
}
synchronized (ASSET_LOCK) {
GameAsset[] assets = lstAssets.toArray(new GameAsset[lstAssets.size()]);
for (GameAsset asset : assets) {
if (lstAssets.contains(asset)) {
asset.update(this, screen);
}
}
screen.repaint(new ArrayList<GameAsset>(lstAssets));
}
}
}
/**
* Allows the removal of an asset...
*/
public void removeAsset(GameAsset asset) {
synchronized (ASSET_LOCK) {
lstAssets.remove(asset);
}
}
/**
* Key event handling...
*/
protected class EventHandler implements AWTEventListener {
#Override
public void eventDispatched(AWTEvent event) {
KeyEvent keyEvent = (KeyEvent) event;
if (keyEvent.getID() == KeyEvent.KEY_PRESSED) {
synchronized (ASSET_LOCK) {
GameAsset[] assets = lstAssets.toArray(new GameAsset[lstAssets.size()]);
for (GameAsset asset : assets) {
if (lstAssets.contains(asset)) {
asset.processKeyPressed(GameEngine.this, screen, keyEvent);
}
}
}
} else if (keyEvent.getID() == KeyEvent.KEY_RELEASED) {
synchronized (ASSET_LOCK) {
GameAsset[] assets = lstAssets.toArray(new GameAsset[lstAssets.size()]);
for (GameAsset asset : lstAssets) {
if (lstAssets.contains(asset)) {
asset.processKeyReleased(GameEngine.this, screen, keyEvent);
}
}
}
}
}
}
}

Swing is not thread safe. Events should be fired on the event-dispatching thread.
http://www.javamex.com/tutorials/threads/invokelater.shtml

Collision detection using plain arrays and rectangles--java

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.

My Bouncing Ball Does Not Draw

I am having a problem getting my application to draw a Ball when i click on the frame.
I thought my code was correct, and I don't get any errors, but it still doesn't work.
I feel the problem is with the MouseListener implementation and that the application is not handling the MouseEvent properly.
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.*;
public class BouncingBallApp extends JFrame
{
public static void main(String[] args)
{
Container container;
BouncingBallApp bouncingBalls = new BouncingBallApp();
bouncingBalls.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
container = new Container();
BouncingBallPanel BBP = new BouncingBallPanel();
container.add(BBP);
bouncingBalls.addMouseListener(BBP);
//addMouseListener;
bouncingBalls.setBackground( Color.WHITE );
bouncingBalls.setSize(400,300);
bouncingBalls.setVisible( true );
}//end of main method
}//end of BouncingBallApp
class BouncingBallPanel extends JPanel implements MouseListener, Runnable
{
private Ball[] ballArray = new Ball[20];
private int ballCount = 0;
public void run()
{
for(int i = 0; i<ballArray.length; i++){
if(ballArray[i] != null){
ballArray[i].move();}}
repaint();
//delay(1);
}
public void mouseClicked(MouseEvent e)
{
ballArray[ballCount] = new Ball();
ballCount++;
if(ballCount == 1)
(new Thread(new BouncingBallPanel())).start();
}
//empty interface methods
public void mouseExited(MouseEvent e){}
public void mouseReleased(MouseEvent e){}
public void mouseEntered(MouseEvent e){}
public void mousePressed(MouseEvent e){}
public void paintComponent(Graphics g)
{
super.paintComponent( g );
Graphics2D g2d = (Graphics2D) g;
for(int i = 0; i<ballArray.length; i++)
{
if(ballArray[i] != null){
g2d.setColor(ballArray[i].getColor());
g2d.fill(new Ellipse2D.Double(ballArray[i].getX(),ballArray[i].getY(),ballArray
[i].getDiameter(),ballArray[i].getDiameter()));}
}//end of for loop
}
}//end of BouncingBallPanel
class Ball
{
private double x;
private double y;
private double deltaX;
private double deltaY;
private double diameter;
private Color color;
Random random = new Random();
public Ball()
{
x = random.nextInt(400);
y = random.nextInt(300);
deltaX = 2;
deltaY = 2;
diameter = 10;
color = new Color(random.nextInt(256),random.nextInt(256),random.nextInt(256));
}//end of constructor
public double getX(){
return x;}
public double getY(){
return y;}
public double getDiameter(){
return diameter;}
public Color getColor(){
return color;}
public void move()
{
x += deltaX;
y += deltaY;
if (x < 0) {
x = 0;
deltaX = -deltaX;}
else if (x > 400) {
x = 400;
deltaX = -deltaX;}
if (y < 0) {
y = 0;
deltaY = -deltaY;}
else if (y > 300) {
y = 300;
deltaY = -deltaY;}
}//end of method move
}//end of ball

3 Things
No size for container
You are not adding container
No loop to update graphics
The code below is working
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.*;
public class BouncingBallApp extends JFrame {
public static void main(String[] args) {
// Container container;
BouncingBallApp bouncingBalls = new BouncingBallApp();
bouncingBalls.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// container = new Container();
BouncingBallPanel BBP = new BouncingBallPanel();
// container.add(BBP);
bouncingBalls.addMouseListener(BBP);
// addMouseListener;
bouncingBalls.setBackground(Color.WHITE);
bouncingBalls.setSize(400, 300);
BBP.setSize(400, 300);
BBP.setLayout(null);
bouncingBalls.setContentPane(BBP);
/*
* JTextField jtf = new JTextField(); BBP.add(jtf); jtf.setSize(100,
* 20);
*/
bouncingBalls.setVisible(true);
}// end of main method
}// end of BouncingBallApp
class BouncingBallPanel extends JPanel implements MouseListener {
private Ball[] ballArray = new Ball[20];
private int ballCount = 0;
public void mouseClicked(MouseEvent e) {
ballArray[ballCount] = new Ball();
ballCount++;
if (ballCount == 1) {
final Runnable updateGraphics = new Runnable() {
public void run() {
for (int i = 0; i < ballArray.length; i++) {
if (ballArray[i] != null) {
ballArray[i].move();
}
}
repaint();
}
};
Runnable animation = new Runnable() {
public void run() {
while (true) {
try {
EventQueue.invokeLater(updateGraphics);
Thread.sleep(100);
} catch (InterruptedException e) {
return;
}
}
}
};
new Thread(animation).start();
}
}
// empty interface methods
public void mouseExited(MouseEvent e) {
}
public void mouseReleased(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mousePressed(MouseEvent e) {
}
public void paintComponent(Graphics g) {
// super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
for (int i = 0; i < ballArray.length; i++) { if (ballArray[i] !=
null) { System.out.println(" ball " + i + " , " +
ballArray[i].getColor() + " , " + ballArray[i].getX() + " , " +
ballArray[i].getY() + " , " + ballArray[i].getDiameter());
g2d.setColor(ballArray[i].getColor());
g2d.fillRect((int)ballArray[i].getX(), (int)ballArray[i].getY(),
(int)ballArray[i].getDiameter(), (int)ballArray[i].getDiameter()); }
}// end of for loop
}
}// end of BouncingBallPanel
class Ball {
private double x;
private double y;
private double deltaX;
private double deltaY;
private double diameter;
private Color color;
Random random = new Random();
public Ball() {
x = random.nextInt(400);
y = random.nextInt(300);
deltaX = 2;
deltaY = 2;
diameter = 10;
color = new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256));
}// end of constructor
public double getX() {
return x;
}
public double getY() {
return y;
}
public double getDiameter() {
return diameter;
}
public Color getColor() {
return color;
}
public void move() {
x += deltaX;
y += deltaY;
if (x < 0) {
x = 0;
deltaX = -deltaX;
}
else if (x > 400) {
x = 400;
deltaX = -deltaX;
}
if (y < 0) {
y = 0;
deltaY = -deltaY;
}
else if (y > 300) {
y = 300;
deltaY = -deltaY;
}
}// end of method move
}// end of ball