Develop Reference

Why aren't my ArrayList items removing themselves when they disapear?

I am trying to get my Asteroids game in Java to have the ArrayList container be removed once it's off screen. I figured out how to stop having it print when off screen, but can see in my console the array continues to grow. Not sure where to go from here.
I think the way I can get them to be removed when off screen is by either using the remove or set feature with arrayLists. Visually everything is disappearing right, but in the console my ArrayList is still growing. I thought about setting a limit of how long it can be, but not sure if there is a better way than that.
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.util.Iterator;
public class AsteroidGame extends Frame {
private int FrameWidth = 500;
private int FrameHeight = 400;
static public void main(String[] args) {
AsteroidGame world = new AsteroidGame();
world.show();
world.run();
}
public AsteroidGame() {
setTitle("Asteroid Game0");
setSize(FrameWidth, FrameHeight);
addKeyListener(new keyDown());
addWindowListener(new CloseQuit());
}
public void run() {
while (true) {
movePieces();
repaint();
try {
Thread.sleep(100);
} catch (Exception e) {
}
}
}
private ArrayList asteroids = new ArrayList();
private ArrayList rockets = new ArrayList();
private Station station = new Station(FrameWidth / 2, FrameHeight - 20);
public void paint(Graphics g) {
station.paint(g);
Iterator astIt = asteroids.iterator();
while (astIt.hasNext()) {
Asteroid rock = (Asteroid) astIt.next();
if (rock.y >= 400 || rock.x >= 500){
rock = null;
} else {
rock.paint(g);
}
}
Iterator rocIt = rockets.iterator();
while (rocIt.hasNext()) {
Rocket rock = (Rocket) rocIt.next();
if (rock.y >= 400 || rock.x >= 500) {
rock = null;
} else {
rock.paint(g);
}
}
}
public void movePieces() {
if (Math.random() < 0.3) {
Asteroid newRock = new Asteroid(FrameWidth * Math.random(), 20, 10 * Math.random() - 5, 3 + 3 * Math.random());
if (newRock.y >= 500 || newRock.x >= 500){
asteroids.remove(0);
} else{
asteroids.add(newRock);
}
System.out.println(asteroids.size());
}
Iterator astIt = asteroids.iterator();
while (astIt.hasNext()) {
Asteroid rock = (Asteroid) astIt.next();
if (rock.y >= 400 || rock.x >= 500) {
rock = null;
} else {
rock.move();
station.checkHit(rock);
}
}
Iterator rocIt = rockets.iterator();
while (rocIt.hasNext()) {
Rocket rock = (Rocket) rocIt.next();
if (rock.y >= 400 || rock.x >= 500) {
rock = null;
} else {
rock.move(asteroids);
}
}
}
private class gameMover extends Thread {
public void run() {
while (true) {
movePieces();
repaint();
try {
sleep(100);
} catch (Exception e) {
}
}
}
}

Change:
rock = null;
to:
astIt.remove();
Assigning null to the variable that has been assigned the value of an element of a List does absolutely nothing to either the List or the element in it; it only affects the value that the variable holds.
As an aside, nice variable name choice of rock - it is appropraite for both types of object - either an abbreviation of "rocket" or a reasonable synonym for an astroid.

Change rock = null; to asteroids.remove(rock); or astIt.remove();
and it should be fine, also no need to set the variable to null as the garbage collector will take care of it for you.
EDIT
Actually asteroids.remove(rock); will throw an exception as said in the comments of this answer, so nevermind it and use the other.
Also I think when in movePieces() you create a new rock and you check if this new rock is outside the screen, I don't think removing the first asteroid in the ArrayList is correct as you will not add the new rock (which may be right if the rock can actually randomly spawn outside the screen) but you will also remove a maybe fine working asteroid from the ArrayList (and thus from the game and the screen).
So, personally I would change that part of code to:
if (Math.random() < 0.3) {
Asteroid newRock = new Asteroid(FrameWidth * Math.random(), 20, 10 * Math.random() - 5, 3 + 3 * Math.random());
if (!(newRock.y >= 500 || newRock.x >= 500)){
asteroids.add(newRock);
}
System.out.println(asteroids.size());
}
But tell me if this works for you.

Java Asteroids game how to be able to fire multiple shots without having the first shot disappear?

So for my final in Java class, we are making an Asteroid game (except a simpler version that the official one, because not enough time).
The problem is when our ship fires a shot (SPACE bar) we add(shot, x, y), but then when we click SPACE bar again it just takes that shot and puts it back to original x, y. So right now we can only fire off one shot at a time to be on the screen. We would like to be able to be able to fire off multiple shots and have them all be visible and stuff.
Not sure how to do that though. Any help is welcome thank you.
P.S. if needed i will add our code.
P.S.S. sorry for posting this again i thought i could edit the post later, thats why i didn't include the code but apparently not.
package week7Homework;
import acm.program.GraphicsProgram;
import java.util.*;
import java.awt.event.*;
import acm.graphics.*;
import java.awt.Color;
import java.awt.Image;
public class space8bit extends GraphicsProgram
{
/* Initialize everything that is needed */
final int WIN_HEIGHT = 800;
final int WIN_WIDTH = 1900;
GImage space = new GImage("/College/IT219/Week7/src/week7Homework/outerspace.png");
GImage ship = new GImage("/College/IT219/Week7/src/week7Homework/ship.png");
GImage explosion = new GImage("/College/IT219/Week7/src/week7Homework/explosion.png");
GImage [] ast = new GImage[6];
Random rand = new Random();
pewpew shots = new pewpew();
int shipx;
int shipy;
public void init()
{
setSize(WIN_WIDTH, WIN_HEIGHT);
add(space);
ship.setLocation(50,330);
ship.scale(.8);
add(ship);
addKeyListeners( );
//scale explosion
explosion.scale(.5);
}
public void keyPressed(KeyEvent e)
{
int key = e.getKeyCode( );
if (key == KeyEvent.VK_UP)
{ ship.move(0, -15); }
/*else if (key == KeyEvent.VK_SPACE)
{ xMove = MV_AMT; }*/
else if (key == KeyEvent.VK_DOWN)
{ ship.move(0, 15); }
else if (key == KeyEvent.VK_SPACE)
{shipx = (int)ship.getX()+195;
shipy = (int)ship.getY() + 80;
add(shots,shipx,shipy);
}
}
public void asteriods()
{
GImage ast1 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1300,100);
GImage ast2 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1750,250);
GImage ast3 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1650,350);
GImage ast4 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1550,650);
GImage ast5 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1450,600);
GImage ast6 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1350,750);
ast [0] = ast1;
ast [1] = ast2;
ast [2] = ast3;
ast [3] = ast4;
ast [4] = ast5;
ast [5] = ast6;
add(ast[0]);
add(ast[1]);
add(ast[2]);
add(ast[3]);
add(ast[4]);
add(ast[5]);
}
public void run()
{
asteriods();
while(true)
{
pause(120);
int random1x = rand.nextInt(-1+1+6)-9;
int random2x = rand.nextInt(-1+1+6)-15;
int random3x = rand.nextInt(-1+1+6)-25;
int random4x = rand.nextInt(-1+1+6)-16;
int random5x = rand.nextInt(-1+1+6)-8;
int random6x = rand.nextInt(-1+1+6)-13;
ast[0].move(random1x, 0);
ast[1].move(random2x, 0);
ast[2].move(random3x, 0);
ast[3].move(random4x, 0);
ast[4].move(random5x, 0);
ast[5].move(random6x, 0);
shots.move(50, 0);
for (int i = 0; i < ast.length; i++)
{
//integer that gets bounds of all rectangles and ovals in the arrays.
GRectangle asteroidBounds = ast[i].getBounds();
//check for collision with other objects
if (shots.getBounds().intersects(asteroidBounds))
{
int shotX = (int)shots.getX();
int shotY = (int)shots.getY();
pause(10);
remove(ast[i]);
add(explosion, shotX-100, shotY - 50);
remove(shots);
pause(25);
remove(explosion);
}
else if (ship.getY() <= 0)
{
ship.move(0, 15);
}
else if (ship.getY() >= WIN_HEIGHT - 168)
{
ship.move(0, -15);
}
}
}
}
}
ALSO HERE IS A SAMPLE CODE, much shorter but does the same thing. Just press SPACEBAR and you will see what im talking about.
package week7Homework;
import acm.graphics.*;
import acm.program.*;
import java.awt.*;
import java.awt.event.*;
public class collisionTry extends GraphicsProgram
{
final int WIN_WIDTH = 500;
final int WIN_HEIGHT = 500;
GOval ship = new GOval(100, 250, 50, 50);
GImage bullet = new GImage("/College/IT219/Week7/src/week7Homework/bullet.gif", 50, 50);
GImage bullet2;
boolean bulletFired;
public void init()
{
setSize(WIN_WIDTH, WIN_HEIGHT);
addKeyListeners();
}
public void run()
{
GRect rect = new GRect(400, 200, 50, 150);
add(rect);
rect.setColor(Color.BLACK);
rect.setFilled(true);
add(ship);
ship.setColor(Color.BLACK);
ship.setFilled(true);
while (true)
{
pause(50);
rect.move(-1, 0);
//bullet.move(5, 0);
if (bulletFired == true)
{
bullet.move(5, 0);
}
if (bullet.getBounds().intersects(rect.getBounds()))
{
remove(rect);
remove(bullet);
}
}
}//run
public void keyPressed(KeyEvent e)
{
int key = e.getKeyCode();
if(key == KeyEvent.VK_SPACE)
{
int shipX = (int)ship.getX();
int shipY = (int)ship.getY();
add(bullet, shipX+50, shipY+25);
bulletFired = true;
}
else if (key == KeyEvent.VK_UP){
ship.move(0, -5);
}
}
}

It's 'cause you only have 1 bullet in the entire game
if (bulletFired == true) {
bullet.move(5, 0);
}
You're telling that one bullet to go back to (5, 0)
You need to find some way of making a new bullet object each time you press space:
if (key == KeyEvent.VK_SPACE) {
int shipX = (int)ship.getX();
int shipY = (int)ship.getY();
Bullet firedBullet = new Bullet(/* params if any, x? y? */);
add(firedBullet, shipX+50, shipY+25);
bulletFired = true;
}
Though this is my vision of how I'd do things, which probably won't work with your game (I don't know what classes you have, their roles etc). But hopefully you can see what I'm getting at and adapt it.
Now because you have multiple bullets, you also have to take care of their lifetimes. You fired 1000 bullets at the start of the game, they go off-screen. You don't want to waste time drawing them for the rest of the game. So whatever list/array you're using to keep track of objects to draw, you gotta periodically find and remove the ones that have gone off-screen.

Can not complete drawline on JButton [closed]

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So I am making a simple tic tac toe game and ran into a problem at the last minute
I am trying to draw a line at the win location but on the final win location(index), the line gets hidden behind the JButton not entirly sure why it is doing this.
I know alot of people say do not use getGraphics(), and I am wondering if that is the source of my issues they say to override the paintComponent method but that is not working for me either
I have attached a pic of what the result is looking like and code snips of how I am trying to perform these actions
PS I am using a JFrame, if any more code is needed I will be glad to show it
if(win[i] == 264){ // if one of the the combinations equal 'X','X','X' which equals 264, then there is a winner
System.out.println("X is the winner!!!");
System.out.println("Game Over!");
number = i;
draw(); }// call draw method
private void draw(){ // drawing a line at winning location
Graphics2D g1 = (Graphics2D) GUI.getFrame().getGraphics(); // declaring graphics on our Jframe
Stroke stroke3 = new BasicStroke(12f, BasicStroke.CAP_ROUND, BasicStroke.JOIN_MITER); // make our strokes cap off round
if(number == 0){ // statements will determine the win location, so at win0, XXX,
g1.setStroke(stroke3); // we will add stroke to our line
g1.drawLine(0,104,500,104); // draw the line starting at the 0,104 and end it at coordinates 500,104
}
here is a more runnable code, it is alot though
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Stroke;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ButtonModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.border.Border;
import javax.swing.border.LineBorder;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class tic implements Runnable {
final static int row = 3; // our rows
final static int col = 3; // our col
final static int sizeOfBoard = row * col;
// the size of our board is not going to change so we make it final
static JButton[] clickButton;
char[] templateOfBoard; // our board, TicTacToe field, static
char userTurn; // users turn , only one letter, tracks whether it is a X or O
int count; // keeps track of user moves
static JFrame frame; // our JFrame
int number;
public tic(JFrame frame) {
tic.frame = new JFrame("TicTacToe GAME");
clickButton = new JButton[9];
count = 0; // number of turns starts at 0;
number = 0;
setUserTurn('X'); // first turn will always be X
setTemplateOfBoard(new char[sizeOfBoard]); // size of the board we are going to make it
try{
for(int spaces=0; spaces<sizeOfBoard; spaces++){ // size of Board is in the GUI class
getTemplateOfBoard()[spaces] = ' '; // the board is being created, looping through all rows and col
//every index of the board not has a char value equal to a space
//determine if everything came out correctly
//should equal of a total of 9
// 3x3
}
System.out.println("Board template created"); // means the board now has all spaces
}
catch(Exception e){
System.out.println("Could not initalize the board to empty char");
e.printStackTrace();
}
}
public static void main(String[] args){
try{
SwingUtilities.invokeLater(new tic(frame)); // run
}
catch(Exception e){ // wanted to test to ensure that Runnable could be invoked
System.out.println("Could not excute Runnable application");
e.printStackTrace();
}
}
public void run() {
setup(); // going to run out setup method, what our game is made out of
}
public void setup() {
// setting up the Board
// board is composed of JButton
// and a 3x3 frame
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // when the user closes the window JFrame will exit
//going to design the board now
//the dimensations of the board = sizeOfBoard
getFrame().setLayout(new GridLayout(row, col)); // this is the outline rows * col
// sizes out row * col based on what we define those numbers as
//i.e 3x3
getFrame().setBounds(0,0,500,500); // location at 0,0, size 500 x 500
Border border = new LineBorder(Color.DARK_GRAY, 2); // color of JButton border
System.out.println("Your board game is being created!");
try{
getFrame().setVisible(true); // shows the board,
// this is going to display everything to the screen
System.out.println("Board is now visable");
}
catch(Exception e){
System.out.println("Board was not displayed");
}
// 9 different buttons, for every index there will be a button
for(int i =0; i<sizeOfBoard;i++){ // going to fill the board with clickableButtons by looping through every index and placing a button there
final int move = i;
clickButton[i] = new JButton(); // at a certain index there is a new button
clickButton[i].setSize(250,250); // size of each button
clickButton[i].setBackground(Color.WHITE); // color of the JButton
getFrame().add(clickButton[i]); // we are going to add the actual the button at that index on the frame
clickButton[i].setFont(new Font("Arial", Font.BOLD, 70)); // size of the text
clickButton[i].setBorder(border); // adding border
clickButton[i].getModel().addChangeListener(new ChangeListener() { //going to overRide what happens when we rollover and press a Butotn
public void stateChanged(ChangeEvent e) {
ButtonModel button = (ButtonModel) e.getSource(); // manages the state of the button, i.e lets me control what happens to the button
if(clickButton[move] != null){ // if we do not include this argument
// the buttons are not made yet on the new game, meaning clickButton[i] = null
//so boolean(!button.isRollover()) will return true, since on the new game you can not have your mouse hovered over
// but when it returns true, it will return a null value, giving a null pointer exception
// so best thing to do, is to only run these cases below when the buttons are not null
if (button.isRollover()) { // when the mouse hovers over the index
clickButton[move].setBackground(Color.BLACK); // color will equal black
}
else if(!button.isRollover()){ // when the button is not hovered over
clickButton[move].setBackground(Color.WHITE); // color will be whte, just like our background
}
}
}
});
clickButton[i].addActionListener(new ActionListener() {
//our click events, going to override to let it know what we want to happen
//once we click on the button
public void actionPerformed(ActionEvent e) {
clickButton[move].setEnabled(false); //going to disable the button after it is clicked
//ORDER: button gets clicked first, then the test is added
mouseListener(e, move); // our mouseListenerEvent in game class
//
}
});
}
}
public static void playAgain() {
try{
System.out.println("NEW GAME");
SwingUtilities.invokeLater(new tic(frame)); // run the run(class) again
}
catch(Exception e){ // wanted to test to ensure that Runnable could be invoked
System.out.println("Could not excute Runnable application");
e.printStackTrace();
}
}
public static JFrame getFrame() {
return frame;
}
public tic userMove(int moveMade){
getTemplateOfBoard()[moveMade] = getUserTurn();
// index of the board, or in simpler terms, where the user
// inserts there turn i.e X or O, 0-8
//System.out.println(userMove);
//boolean statement to determine the turns
// So user X starts first
//if the turn is X, the nextTurn is now O,
if(getUserTurn() == 'X'){
setUserTurn('O');
}
else {
setUserTurn('X');
}
count++;
return this; // going to return the userTurn
// issue actually entering the userTurn is not giving right value, but using 'this' does
}
// for some odd reason the toString is causing some issues, keep getting #hash code
//saw online to override it like this
// will make the board out of emepty strings
// going to return a string representation of an object
public String toString(){
return new String(getTemplateOfBoard());
}
public void mouseListener(ActionEvent e, int moveMade){
// mouse click events
// what happens after a button is clicked
if(getTemplateOfBoard()[moveMade] == ' '){ // the user can only space a click, so an letter on the field if it is empty
((JButton)e.getSource()).setText(Character.toString(getUserTurn())); // when the button is clicked, we want an X placed there
if (getUserTurn() == 'X'){
UIManager.getDefaults().put("Button.disabledText",Color.RED); // when the but gets disabled the test will turn red
}
else{
UIManager.getDefaults().put("Button.disabledText",Color.BLUE);
}
//calling the method userTurn to determine who goes next
//problem is that is expects a String
//going to override the toString method
userMove(moveMade); // calling userMove in moveMade, moveMade is the index at which the user put either an X or a O
winner(); // we want to check each time to ensure there was/was not a winner
}
}
public tic winner() { // determines who is the winner
//list below defines all the possible win combinations
// the index of where a X or O can be place
// placed the locations to a int value
int win1 = templateOfBoard[0] + templateOfBoard[1] + templateOfBoard[2];
int win2 = templateOfBoard[3] + templateOfBoard[4] + templateOfBoard[5];
int win3 = templateOfBoard[6] + templateOfBoard[7] + templateOfBoard[8];
int win4 = templateOfBoard[0] + templateOfBoard[3] + templateOfBoard[6];
int win5 = templateOfBoard[1] + templateOfBoard[4] + templateOfBoard[7];
int win6 = templateOfBoard[2] + templateOfBoard[5] + templateOfBoard[8];
int win7 = templateOfBoard[0] + templateOfBoard[4] + templateOfBoard[8];
int win8 = templateOfBoard[2] + templateOfBoard[4] + templateOfBoard[6];
int[] win = new int[]{win1,win2,win3,win4,win5,win6,win7,win8};
// making a array to go through all the possibile wins
//possible total of wins is 8
for(int i = 0;i<win.length;i++){
// looping through the win possibilities
if(win[i] == 264){ // if one of the the combinations equal 'X','X','X' which equals 264, then there is a winner
System.out.println("X is the winner!!!");
System.out.println("Game Over!");
number = i;
draw(); // call draw method
return this; // if statement is true, it will return this(gameOver)
}
else if(win[i] == 237 ){ // if one of the the combinations equal 'O','O','O' which equals 234, then there is a winner
System.out.println("O is the winner!!!");
System.out.println("Game Over!");
number = i;
//draw(); // call draw method
return this;
}
if (count == 9) {
// if none of the statements above are true, it automatically comes done to here
//so if there is nine moves and no win, it is a draw
}
}
return this;
// going to return this method ;
}
private void draw(){ // drawing a line at winning location
Graphics2D g1 = (Graphics2D) getFrame().getGraphics(); // declaring graphics on our Jframe
Stroke stroke3 = new BasicStroke(12f, BasicStroke.CAP_ROUND, BasicStroke.JOIN_MITER); // make our strokes cap off round
if(number == 0){ // statements will determine the win location, so at win0, XXX,
g1.setStroke(stroke3); // we will add stroke to our line
g1.drawLine(0,104,500,104); // draw the line starting at the 0,104 and end it at coordinates 500,104
}
else if(number == 1){
g1.setStroke(stroke3);
g1.drawLine(0,257,500,257);
}
else if(number == 2){
g1.setStroke(stroke3);
g1.drawLine(0,411,500,411);
}
else if(number == 3){
g1.setStroke(stroke3);
g1.drawLine(88,0,88,500);
}
else if(number == 4){
g1.setStroke(stroke3);
g1.drawLine(250,0,250,500);
}
else if(number == 5){
g1.setStroke(stroke3);
g1.drawLine(411,0,411,500);
}
else if(number == 6){
g1.setStroke(stroke3);
g1.drawLine(-22,0,500,500);
}
else if(number == 7){
g1.setStroke(stroke3);
g1.drawLine(520,0,0,500);
}
}
// want to be able to access the private variables
//so we will make getter and setter methods for the ones that we need
public char getUserTurn() { // getter method for userTurn
return userTurn;
}
public void setUserTurn(char userTurn) { // setter method
this.userTurn = userTurn;
}
public char[] getTemplateOfBoard() { //getter method
return templateOfBoard;
}
public void setTemplateOfBoard(char[] templateOfBoard) { // setter method
this.templateOfBoard = templateOfBoard;
}
}

Painting over the top of components can be troublesome, you can't override the paintComponent method of the container which contains the components, because this paints in the background, you can't override the paint method of the container, as child components can be painted without the parent container been notified...
You could add a transparent component over the whole lot, but this just introduces more complexity, especially when a component already already exists ...
public class ConnectTheDots {
public static void main(String[] args) {
new ConnectTheDots();
}
public ConnectTheDots() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
PaintPane pp = new PaintPane();
JFrame frame = new JFrame("Test");
frame.setGlassPane(pp);
pp.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new DotsPane(pp));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class PaintPane extends JPanel {
private List<JButton[]> connections;
private JButton lastSelected;
public PaintPane() {
setOpaque(false);
connections = new ArrayList<>(25);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
if (lastSelected != null) {
g2d.setColor(Color.RED);
int x = lastSelected.getX() + ((lastSelected.getWidth() - 8) / 2);
int y = lastSelected.getY() + ((lastSelected.getHeight() - 8) / 2);
g2d.fillOval(x, y, 8, 8);
}
for (JButton[] group : connections) {
g2d.setColor(Color.BLUE);
Point startPoint = group[0].getLocation();
Point endPoint = group[1].getLocation();
startPoint.x += (group[0].getWidth() / 2);
startPoint.y += (group[1].getHeight()/ 2);
endPoint.x += (group[0].getWidth() / 2);
endPoint.y += (group[1].getHeight()/ 2);
g2d.draw(new Line2D.Float(startPoint, endPoint));
}
g2d.dispose();
}
protected void buttonClicked(JButton btn) {
if (lastSelected == null) {
lastSelected = btn;
} else {
connections.add(new JButton[]{lastSelected, btn});
lastSelected = null;
}
revalidate();
repaint();
}
}
public class DotsPane extends JPanel {
private PaintPane paintPane;
public DotsPane(final PaintPane pp) {
paintPane = pp;
ActionListener al = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
JButton btn = (JButton) e.getSource();
paintPane.buttonClicked(btn);
}
};
setLayout(new GridLayout(6, 6));
for (int index = 0; index < 6 * 6; index++) {
JButton btn = new JButton(".");
add(btn);
btn.addActionListener(al);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
}
Take a look at How to Use Root Panes for more details

pattern when using Math.random

I am trying to have a mouse go through rooms to a target room. I am using a graph-like system with an x and y axis. I have a problem where the computer doesn't seem to want to add or subtract from an already existing variable.
Console:
The mouse is in room (5,4)
The mouse is in room (5,6)
The mouse is in room (6,5)
The mouse is in room (5,4)
The mouse is in room (5,6)
The mouse is in room (5,6)
Code for mouse:
package mouse_maze;
public class Mouse {
private int xCord = 5;
private int yCord = 5;
//position of the mouse when it starts
public int getXCord() {
return this.xCord;
}
public int getYCord() {
return this.yCord;
}
public void move() {
//method for the movement of the mouse
boolean verticalMove = Math.random() < .5;
boolean horizontalMove;
if (verticalMove == true)
horizontalMove = false;
else
horizontalMove = true;
int moveBy = 1;
if (Math.random() < .5)
moveBy = -1;
if (verticalMove) {
int test = this.yCord + moveBy;
if(test < 1 || test > 9) return;
this.yCord += moveBy;
}
if (horizontalMove) {
int test = this.xCord + moveBy;
if(test < 1 || test > 9) return;
this.xCord += moveBy;
}
System.out.println("The mouse is in room (" + xCord + "," + yCord + ")");
}
}
Code for maze:
package mouse_maze;
public class Maze {
private boolean onGoing = false;
private int tarX;
private int tarY;
//creates the target for the mouse.
public static void main(String[] args) {
new Maze(6, 8).init();
}
public Maze(int tarX, int tarY) {
this.tarX = tarX;
this.tarY = tarY;
}
public void init() {
this.onGoing = true;
while(this.onGoing)
this.iterate();
}
public void iterate() {
Mouse m = new Mouse();
m.move();
if (m.getXCord() == tarX && m.getYCord() == tarY) {
this.onGoing = false;
System.out.println("The mouse has beat the maze!");
//checks if the mouse has gotten to the target room.
}
}
}

First, learn to use a debugger, or at least learn to debug by whatever means. It is meaningless to always "assume" the problem without actually proving it.
Your whole problem has nothing to do with random etc.
In your iterate() method, you are creating a new mouse every time, instead of having the same mouse keep on moving.

2D Scrolling Game: Firing Bullets. Everything runs properly theres just no image

So heres some code to begin. I first created a class called Bullet. This is where the image should be loaded.
package gameLibrary;
import java.awt.*;
import javax.swing.ImageIcon;
public class Bullet {
int x,y;
Image img;
boolean visible;
public Bullet(int startX, int startY) {
x = startX;
y = startY;
ImageIcon newBullet = new ImageIcon("/resources/bullet.png");
img = newBullet.getImage();
System.out.println("constructor Bullet is called");
visible = true;
}
public void move(){
x = x + 1;
if(x > 854){
System.out.println("Bullet is moving at X = " + x);
visible = false;
}
}
public int getX(){
return x;
}
public int getY() {
return y;
}
public boolean getVisible(){
return visible;
}
public Image getImage(){
return img;
}
}
when the space bar is pressed it calls a method called fire() where a new Bullet(X, Y); is called and then stores it in an ArrayList.
public void fire(){
if(ammo > 0) {
Bullet z = new Bullet(left + 60, y + 70);
bullets.add(z);
ammo--;
}
}
public static ArrayList getBullets(){
return bullets;
}
This code moves the bullet across the screen.
ArrayList bullets = Character.getBullets();
for(int i = 0; i < bullets.size(); i++){
Bullet m = (Bullet) bullets.get(i);
if(m.getVisible() == true){
m.move();
}if(m.getVisible() == false) {
bullets.remove(i);
}
}
And Finally code for the print method.
ArrayList bullets = Character.getBullets();
for(int i = 0; i < bullets.size(); i++){
Bullet m = (Bullet) bullets.get(0);
g2d.drawImage(m.getImage(),m.getX(),m.getY(), null);
}
I cant find where I went wrong. the functioning of the bullet is all working as far as I can tell its just the printing of the image on the screenAny suggestions is much appreciated.

Normally resources are loaded with Class.getResource
ImageIcon newBullet = new ImageIcon(Bullet.class.getResource("resources/bullet.png"));
Of course the resources folder should be in the same package (i.e. in the same folder) as your Bullet class.
That code should always work whether your game is in a jar or not.

I think your resource path is not in the good format.
ImageIcon icon = new ImageIcon("gameLibrary.resources.bullet.png");
if this doesn't work try this code to get your png path:
import java.io.File;
public class GetPath
{
public static void main(String[] args)
{
System.out.println("The user directory: " + System.getProperty("user.dir"));
File fubar = new File("Fubar.txt");
System.out.println("Where Java thinks file is located: " + fubar.getAbsolutePath());
}
}
Tell me what happens.