Olá
Estou escrevendo um código e recentemente me ocorreu um erro que não consigo resolver.
É o NullPointerExeception. Bom, básicamente quando eu vou rodar o meu programa a janela fica completamente em branco e aparece a seguinte mensagem de erro :
Exception in thread “Thread-0” java.lang.NullPointerException
at com.dudu.world.World.render(World.java:48)
at com.dudu.main.Game.render(Game.java:107)
at com.dudu.main.Game.run(Game.java:131)
at java.base/java.lang.Thread.run(Thread.java:834)
Irei colocar abaixo o código para que alguém possa entender e me ajudar.
[CÓDIGO]
package com.dudu.world;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
public class World {
private Tile[] tiles;
public static int WIDTH,HEIGHT;
public World(String path) {
try {
BufferedImage map = ImageIO.read(getClass().getResource(path));
int[] pixels = new int[map.getWidth()*map.getHeight()];
WIDTH = map.getWidth();
HEIGHT = map.getHeight();
tiles = new Tile[map.getWidth()*map.getHeight()];
map.getRGB(0, 0, map.getWidth(), map.getHeight(),pixels, 0, map.getWidth());
for(int xx = 0; xx < map.getWidth(); xx++){
for(int yy = 0; yy < map.getHeight(); yy++){
int pixelAtual = pixels[xx + (yy*map.getWidth())];
if(pixelAtual == 0xFF000000){
tiles[xx + (yy * WIDTH)] = new FloorTile(xx*16,yy*16,Tile.TILE_FLOOR);
}else if(pixelAtual == 0xFFFFFFFF) {
tiles[yy + (xx * WIDTH)] = new WallTile(yy*16,xx*16,Tile.TILE_WALL);
}else if(pixelAtual == 0xFFFFFF) {
tiles[yy + (xx * WIDTH)] = new WallTile(yy*16,xx*16,Tile.TILE_FLOOR);
}else {
tiles[yy + (xx * WIDTH)] = new WallTile(yy*16,xx*16,Tile.TILE_FLOOR);
}
}
}
}catch (IOException e) {
e.printStackTrace();
}
}
public void render(Graphics g) {
for(int xx = 0; xx < WIDTH; xx++ ) {
for(int yy = 0; yy < HEIGHT; yy++) {
Tile tile = tiles[xx + (yy*WIDTH)];
tile.render(g);
}
}
}
}
[CÓDIGO]
package com.dudu.main;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import com.dudu.entities.Entity;
import com.dudu.entities.Player;
import com.dudu.graficos.Spritesheet;
import com.dudu.world.World;
public class Game extends Canvas implements Runnable,KeyListener{
/**
*
*/
private static final long serialVersionUID = 1L;
public static JFrame frame;
private Thread thread;
private boolean isRunning = true;
private final int WIDTH = 240;
private final int HEIGHT = 160;
private final int SCALE = 3;
private BufferedImage image;
public List<Entity> entities;
public static Spritesheet spritesheet;
public static World world;
private Player player;
public Game(){
addKeyListener(this);
setPreferredSize(new Dimension(WIDTH*SCALE,HEIGHT*SCALE));
initFrame();
image = new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB);
entities = new ArrayList<Entity>();
spritesheet = new Spritesheet("/spritesheet.png");
world = new World("/map.png");
player = new Player(0,0,16,16,spritesheet.getSprite(36, 0, 16, 16));
entities.add(player);
}
public void initFrame() {
frame = new JFrame("Teste #1");
frame.add(this);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.pack();
}
public synchronized void start() {
thread = new Thread(this);
isRunning = true;
thread.start();
}
public synchronized void stop() {
isRunning = false;
try {
thread.join();
}catch (InterruptedException e) {
e.printStackTrace();
}
}
public static void main(String[] args){
Game game = new Game();
game.start();
}
public void tick() {
requestFocus();
for(int i = 0; i < entities.size(); i++) {
Entity e = entities.get(i);
e.tick();
}
}
public void render() {
BufferStrategy bs = this.getBufferStrategy();
if(bs== null) {
this.createBufferStrategy(3);
return;
}
Graphics g = image.getGraphics();
g.setColor(new Color(0,0,0));
g.fillRect(0, 0, WIDTH,HEIGHT);
//Graphics2D g2 = (Graphics2D) g;
world.render(g);
for(int i = 0; i < entities.size(); i++) {
Entity e = entities.get(i);
e.render(g);
g.dispose();
g = bs.getDrawGraphics();
g.drawImage(image, 0, 0, WIDTH*SCALE,HEIGHT*SCALE,null);
bs.show();
}
}
public void run() {
long lastTime = System.nanoTime();
double amountOfTicks = 60.0;
double ns = 1000000000 / amountOfTicks;
double delta = 0;
int frames = 0;
double timer = System.currentTimeMillis();
while (isRunning) {
long now = System.nanoTime();
delta+= (now - lastTime) / ns;
lastTime = now;
if(delta >= 1) {
tick();
render();
frames++;
delta--;
}
if(System.currentTimeMillis() - timer >= 1000) {
System.out.println("Fps: "+ frames);
frames = 0;
timer+=1000;
}
}
stop();
}
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyPressed(KeyEvent e) {
if(e.getKeyCode() == KeyEvent.VK_RIGHT||
e.getKeyCode() == KeyEvent.VK_D) {
player.right = true;
}else if(e.getKeyCode() == KeyEvent.VK_LEFT||
e.getKeyCode() == KeyEvent.VK_A){
player.left = true;
}
if(e.getKeyCode() == KeyEvent.VK_UP||
e.getKeyCode() == KeyEvent.VK_W) {
player.up = true;
}else if(e.getKeyCode() == KeyEvent.VK_DOWN||
e.getKeyCode() == KeyEvent.VK_S) {
player.down = true;
}
}
@Override
public void keyReleased(KeyEvent e) {
if(e.getKeyCode() == KeyEvent.VK_RIGHT||
e.getKeyCode() == KeyEvent.VK_D) {
player.right = false;
}else if(e.getKeyCode() == KeyEvent.VK_LEFT||
e.getKeyCode() == KeyEvent.VK_A){
player.left = false;
}
if(e.getKeyCode() == KeyEvent.VK_UP||
e.getKeyCode() == KeyEvent.VK_W) {
player.up = false;
}else if(e.getKeyCode() == KeyEvent.VK_DOWN||
e.getKeyCode() == KeyEvent.VK_S) {
player.down = false;
}
}
}
[CÓDIGO]
package com.dudu.main;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import com.dudu.entities.Entity;
import com.dudu.entities.Player;
import com.dudu.graficos.Spritesheet;
import com.dudu.world.World;
public class Game extends Canvas implements Runnable,KeyListener{
/**
*
*/
private static final long serialVersionUID = 1L;
public static JFrame frame;
private Thread thread;
private boolean isRunning = true;
private final int WIDTH = 240;
private final int HEIGHT = 160;
private final int SCALE = 3;
private BufferedImage image;
public List<Entity> entities;
public static Spritesheet spritesheet;
public static World world;
private Player player;
public Game(){
addKeyListener(this);
setPreferredSize(new Dimension(WIDTH*SCALE,HEIGHT*SCALE));
initFrame();
image = new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB);
entities = new ArrayList<Entity>();
spritesheet = new Spritesheet("/spritesheet.png");
world = new World("/map.png");
player = new Player(0,0,16,16,spritesheet.getSprite(36, 0, 16, 16));
entities.add(player);
}
public void initFrame() {
frame = new JFrame("Teste #1");
frame.add(this);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.pack();
}
public synchronized void start() {
thread = new Thread(this);
isRunning = true;
thread.start();
}
public synchronized void stop() {
isRunning = false;
try {
thread.join();
}catch (InterruptedException e) {
e.printStackTrace();
}
}
public static void main(String[] args){
Game game = new Game();
game.start();
}
public void tick() {
requestFocus();
for(int i = 0; i < entities.size(); i++) {
Entity e = entities.get(i);
e.tick();
}
}
public void render() {
BufferStrategy bs = this.getBufferStrategy();
if(bs== null) {
this.createBufferStrategy(3);
return;
}
Graphics g = image.getGraphics();
g.setColor(new Color(0,0,0));
g.fillRect(0, 0, WIDTH,HEIGHT);
//Graphics2D g2 = (Graphics2D) g;
world.render(g);
for(int i = 0; i < entities.size(); i++) {
Entity e = entities.get(i);
e.render(g);
g.dispose();
g = bs.getDrawGraphics();
g.drawImage(image, 0, 0, WIDTH*SCALE,HEIGHT*SCALE,null);
bs.show();
}
}
public void run() {
long lastTime = System.nanoTime();
double amountOfTicks = 60.0;
double ns = 1000000000 / amountOfTicks;
double delta = 0;
int frames = 0;
double timer = System.currentTimeMillis();
while (isRunning) {
long now = System.nanoTime();
delta+= (now - lastTime) / ns;
lastTime = now;
if(delta >= 1) {
tick();
render();
frames++;
delta--;
}
if(System.currentTimeMillis() - timer >= 1000) {
System.out.println("Fps: "+ frames);
frames = 0;
timer+=1000;
}
}
stop();
}
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyPressed(KeyEvent e) {
if(e.getKeyCode() == KeyEvent.VK_RIGHT||
e.getKeyCode() == KeyEvent.VK_D) {
player.right = true;
}else if(e.getKeyCode() == KeyEvent.VK_LEFT||
e.getKeyCode() == KeyEvent.VK_A){
player.left = true;
}
if(e.getKeyCode() == KeyEvent.VK_UP||
e.getKeyCode() == KeyEvent.VK_W) {
player.up = true;
}else if(e.getKeyCode() == KeyEvent.VK_DOWN||
e.getKeyCode() == KeyEvent.VK_S) {
player.down = true;
}
}
@Override
public void keyReleased(KeyEvent e) {
if(e.getKeyCode() == KeyEvent.VK_RIGHT||
e.getKeyCode() == KeyEvent.VK_D) {
player.right = false;
}else if(e.getKeyCode() == KeyEvent.VK_LEFT||
e.getKeyCode() == KeyEvent.VK_A){
player.left = false;
}
if(e.getKeyCode() == KeyEvent.VK_UP||
e.getKeyCode() == KeyEvent.VK_W) {
player.up = false;
}else if(e.getKeyCode() == KeyEvent.VK_DOWN||
e.getKeyCode() == KeyEvent.VK_S) {
player.down = false;
}
}
}
Sou novo na programação e sei muito pouco, espero que possam ajudar.