我正在开发一款游戏＆＃34;当我点击Canvas时遇到问题。 KeyManager无法加载并崩溃。但是当尝试使用KeyEvent加载它时，它可以正常工作。
我的代码是：
//Click Event
public class MouseManager implements MouseListener {
private GameState gameState;
private Game game;
public boolean enter;
public MouseManager(){
}
@Override
public void mouseClicked(MouseEvent e){
if (State.getState().toString().contains("MenuState")) {
for (int x = 187; x < 287; x++) {
for (int y = 400; y < 430; y++) {
if (e.getX() == x && e.getY() == y) {
this.gameState = new GameState(this.game);
State.setState(this.gameState);
break;
}
}
}
} else {
return;
}
}
@Override
public void mouseEntered(MouseEvent e){
}
@Override
public void mouseExited(MouseEvent e){
}
@Override
public void mousePressed(MouseEvent e){
}
@Override
public void mouseReleased(MouseEvent e){
}
}
//Game State class
public GameState(Game game){
super(game);
this.player = new Player(game, 100.0F, 100.0F);
this.friend = new Friend(100.0F, 100.0F);
this.world = new World("res/worlds/world1.txt");
}
//State class
private static State currentState = null;
protected Game game;
public static void setState(State state){
currentState = state;
}
public static State getState(){
return currentState;
}
public State(Game game){
this.game = game;
}
public abstract void tick();
public abstract void render(Graphics paramGraphics);
//GameState class
public class GameState extends State {
private Player player;
private Friend friend;
private World world;
public GameState(Game game){
super(game);
this.player = new Player(game, 100.0F, 100.0F);
this.friend = new Friend(100.0F, 100.0F);
this.world = new World("res/worlds/world1.txt");
}
public void tick(){
this.world.tick();
this.player.tick(); //line 25
this.friend.tick();
}
public void render(Graphics g){
this.world.render(g);
this.player.render(g);
this.friend.render(g);
}
//Player
public class Player extends Creature {
private Game game;
private int onMoveDown = 0;
private int onMoveUp = 0;
private int onMoveLeft = 0;
private int onMoveRight = 0;
public Player(Game game, float x, float y){
super(x, y, 64, 64);
this.game = game;
}
private void getInput(){
this.xMove = 0.0F;
this.yMove = 0.0F;
float vol = -40.0F;
SpriteAngel angel = new SpriteAngel(ImageLoader.loadImage("/sprites/angel.png"));
if (this.game.getKeyManager().up) { //line 31
this.yMove = (-this.speed);
onMoveLeft = 0;
onMoveRight = 0;
onMoveDown = 0;
if (onMoveUp == 6) {
Assets.player = angel.crop(80, 192, 80, 64);
}
if (onMoveUp == 12) {
Assets.player = angel.crop(160, 192, 80, 64);
}
if (onMoveUp == 15) {
Assets.player = angel.crop(240, 192, 80, 64);
}
if (onMoveUp == 21) {
onMoveUp = 0;
}
onMoveUp++;
Sounds.playSound("res/sounds/walk.wav", vol);
}
if (this.game.getKeyManager().down) {
this.yMove = this.speed;
onMoveLeft = 0;
onMoveRight = 0;
onMoveUp = 0;
if (onMoveDown == 6) {
Assets.player = angel.crop(80, 0, 80, 64);
}
if (onMoveDown == 12) {
Assets.player = angel.crop(160, 0, 80, 64);
}
if (onMoveDown == 15) {
Assets.player = angel.crop(240, 0, 80, 64);
}
if (onMoveDown == 21) {
onMoveDown = 0;
}
onMoveDown++;
Sounds.playSound("res/sounds/walk.wav", vol);
}
if (this.game.getKeyManager().left) {
this.xMove = (-this.speed);
onMoveRight = 0;
onMoveUp = 0;
onMoveDown = 0;
if (onMoveLeft == 6) {
Assets.player = angel.crop(80, 64, 80, 64);
}
if (onMoveLeft == 12) {
Assets.player = angel.crop(160, 64, 80, 64);
}
if (onMoveLeft == 15) {
Assets.player = angel.crop(240, 64, 80, 64);
}
if (onMoveLeft == 21) {
onMoveLeft = 0;
}
onMoveLeft++;
Sounds.playSound("res/sounds/walk.wav", vol);
}
if (this.game.getKeyManager().right) {
this.xMove = this.speed;
onMoveLeft = 0;
onMoveUp = 0;
onMoveDown = 0;
if (onMoveRight == 6) {
Assets.player = angel.crop(80, 128, 80, 64);
}
if (onMoveRight == 12) {
Assets.player = angel.crop(160, 128, 80, 64);
}
if (onMoveRight == 15) {
Assets.player = angel.crop(240, 128, 80, 64);
}
if (onMoveRight == 21) {
onMoveRight = 0;
}
onMoveRight++;
Sounds.playSound("res/sounds/walk.wav", vol);
}
if (this.game.getKeyManager().shift) {
setSpeed(DEFAULT_SPEED + 1.7F);
} else {
setSpeed(DEFAULT_SPEED);
}
}
public void tick(){
getInput(); //line 132
move();
}
public void render(Graphics g){
g.drawImage(Assets.player, (int) this.x, (int) this.y, null);
}
//Game.java:53
private void tick(){
this.keyManager.tick();
this.mouseManager.tick();
if (State.getState() != null) {
State.getState().tick();
}
}
在线出错
if (this.game.getKeyManager().up) {
}
Loader class
this.display.getCanvas().addMouseListener(this.mouseManager);
错误
Exception in thread "Thread-0" java.lang.NullPointerException
at com.gmail.cadox8.deud.entities.creatures.Player.getInput(Player.java:31)
at com.gmail.cadox8.deud.entities.creatures.Player.tick(Player.java:132)
at com.gmail.cadox8.deud.states.GameState.tick(GameState.java:25)
at com.gmail.cadox8.deud.Game.tick(Game.java:53)
at com.gmail.cadox8.deud.Game.run(Game.java:89)
at java.lang.Thread.run(Unknown Source)
//编辑代码
答案 0 :(得分：0)
你的mouseClicked（）有点奇怪，我想你的意思是
@Override
public void mouseClicked(MouseEvent e){
if (State.getState().toString().contains("MenuState")) {
if (e.getX() >= 187
&& e.getX() < 287
&& e.getY() >= 400
&& e.getY() < 430) {
this.gameState = new GameState(this.game);
State.setState(this.gameState);
}
}
} else {
return;
}
}
但这可能不是你问题的原因，请查看Game.java:89 什么是null。
答案 1 :(得分：0)
注册mouseListener时，请尝试如下：.addMouseListener（this）; 我自己有点新鲜，但似乎我过去就这样做了。