将按钮添加到 Java Applet
Add a button to Java Applet
我想使用此代码向页面添加一个按钮，当游戏状态为 Dead 或 Win 时显示。此按钮将让用户重新开始或继续到下一个级别。我的动作侦听器尚未完全编码，因为我什至无法让按钮在页面上可见。我尝试使用
在按钮中编码
setLayout(new FlowLayout());
this.add(sOver);
sOver = new Button("Start Over");
sOver.addActionListener(this);
但这会在游戏更改状态时导致错误。
package androidGame;
import java.applet.Applet;
import java.awt.event.*;
import java.applet.AudioClip;
import java.awt.Button;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Random;
import java.net.*;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.Clip;
import androidGame.framework.Animation;
import java.applet.Applet;
import java.applet.AudioClip;
import java.net.URL;
public class StartingClass extends Applet implements Runnable, KeyListener, ActionListener {
enum GameState {
Running, Dead, Win
}
GameState state = GameState.Running;
private static Robot robot;
public static Heliboy hb, hb2, hb3, hb4, hb5, hb6, hb7, hb8, hb9, hb10, hb11, hb12, hb13, hb14, hb15, hb16;
public static int score = 0;
public static int rHealth = 120;
private Font font = new Font(null, Font.BOLD, 30);
private Image image, currentSprite, character, character2, character3,
characterDown, characterJumped, background, heliboy, heliboy2,
heliboy3, heliboy4, heliboy5;
public static Image tilegrassTop, tilegrassBot, tilegrassLeft,
tilegrassRight, tiledirt, tilefire, tiledoor;
private Graphics second;
private URL base;
private static Background bg1, bg2;
private Animation anim, hanim;
int level = 1;
AudioClip clip;
Button next, sOver;
private ArrayList<Tile> tilearray = new ArrayList<Tile>();
@Override
public void init() {
setSize(800, 480);
setBackground(Color.BLACK);
setFocusable(true);
addKeyListener(this);
Frame frame = (Frame) this.getParent().getParent();
frame.setTitle("Robot Mania");
try {
base = getDocumentBase();
} catch (Exception e) {
// TODO: handle exception
}
// Image Setups
character = getImage(base, "data/character.png");
character2 = getImage(base, "data/character2.png");
character3 = getImage(base, "data/character3.png");
characterDown = getImage(base, "data/down.png");
characterJumped = getImage(base, "data/jumped.png");
heliboy = getImage(base, "data/heliboy.png");
heliboy2 = getImage(base, "data/heliboy2.png");
heliboy3 = getImage(base, "data/heliboy3.png");
heliboy4 = getImage(base, "data/heliboy4.png");
heliboy5 = getImage(base, "data/heliboy5.png");
background = getImage(base, "data/spacebackground.png");
tiledirt = getImage(base, "data/tiledirt.png");
tilegrassTop = getImage(base, "data/tilegrasstop.png");
tilegrassBot = getImage(base, "data/tilegrassbot.png");
tilegrassLeft = getImage(base, "data/tilegrassleft.png");
tilegrassRight = getImage(base, "data/tilegrassright.png");
tilefire = getImage(base, "data/tilefire.png");
tiledoor = getImage(base, "data/tiledoor.png");
anim = new Animation();
anim.addFrame(character, 1250);
anim.addFrame(character2, 50);
anim.addFrame(character3, 50);
anim.addFrame(character2, 50);
hanim = new Animation();
hanim.addFrame(heliboy, 100);
hanim.addFrame(heliboy2, 100);
hanim.addFrame(heliboy3, 100);
hanim.addFrame(heliboy4, 100);
hanim.addFrame(heliboy5, 100);
hanim.addFrame(heliboy4, 100);
hanim.addFrame(heliboy3, 100);
hanim.addFrame(heliboy2, 100);
currentSprite = anim.getImage();
}
@Override
public void start() {
//Sound.MAIN.loop();
bg1 = new Background(0, 0);
bg2 = new Background(2160, 0);
robot = new Robot();
// Initialize Tiles
try {
loadMap("data/map"+ level +".txt");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Random random = new Random();
int randomInt = random.nextInt(500);
hb = new Heliboy(700, 360);
hb2 = new Heliboy(900 + randomInt, 360);
hb3 = new Heliboy(2300 + randomInt, 360);
hb4 = new Heliboy(2900 + randomInt, 360);
hb5 = new Heliboy(3400 + randomInt, 360);
hb6 = new Heliboy(3900 + randomInt, 360);
hb7 = new Heliboy(4300 + randomInt, 360);
hb8 = new Heliboy(4700 + randomInt, 360);
hb9 = new Heliboy(5000 + randomInt, 360);
hb10 = new Heliboy(5300 + randomInt, 360);
hb11 = new Heliboy(5700 + randomInt, 360);
hb12 = new Heliboy(6000 + randomInt, 360);
hb13 = new Heliboy(6300 + randomInt, 360);
hb14 = new Heliboy(6700 + randomInt, 360);
hb15 = new Heliboy(7000 + randomInt, 360);
hb16 = new Heliboy(7200 + randomInt, 360);
Thread thread = new Thread(this);
thread.start();
}
private void loadMap(String filename) throws IOException {
ArrayList lines = new ArrayList();
int width = 0;
int height = 0;
BufferedReader reader = new BufferedReader(new FileReader(filename));
while (true) {
String line = reader.readLine();
// no more lines to read
if (line == null) {
reader.close();
break;
}
if (!line.startsWith("!")) {
lines.add(line);
width = Math.max(width, line.length());
}
}
height = lines.size();
for (int j = 0; j < 12; j++) {
String line = (String) lines.get(j);
for (int i = 0; i < width; i++) {
if (i < line.length()) {
char ch = line.charAt(i);
Tile t = new Tile(i, j, Character.getNumericValue(ch));
tilearray.add(t);
}
}
}
}
@Override
public void run() {
if (state == GameState.Running) {
while (true) {
robot.update();
if (robot.isJumped()) {
currentSprite = characterJumped;
} else if (robot.isJumped() == false
&& robot.isDucked() == false) {
currentSprite = anim.getImage();
}
ArrayList projectiles = robot.getProjectiles();
for (int i = 0; i < projectiles.size(); i++) {
Projectile p = (Projectile) projectiles.get(i);
if (p.isVisible() == true) {
p.update();
} else {
projectiles.remove(i);
}
}
updateTiles();
hb.update();
hb2.update();
hb3.update();
hb4.update();
hb5.update();
hb6.update();
hb7.update();
hb8.update();
hb9.update();
hb10.update();
hb11.update();
hb12.update();
hb13.update();
hb14.update();
hb15.update();
hb16.update();
bg1.update();
bg2.update();
animate();
repaint();
try {
Thread.sleep(17);
} catch (InterruptedException e) {
e.printStackTrace();
}
if (rHealth == 0) {
state = GameState.Dead;
Sound.MAIN.stop();
//Sound.DIE.play();
sOver = new Button("Start Over");
this.add(sOver);
sOver.addActionListener(this);
sOver.setVisible(true);
revalidate();
repaint();
}
if (robot.getCenterY() > 500) {
state = GameState.Dead;
Sound.MAIN.stop();
//Sound.DIE.play();
sOver = new Button("Start Over");
this.add(sOver);
sOver.addActionListener(this);
sOver.setVisible(true);
revalidate();
repaint();
}
if (score == 5){
state = GameState.Win;
Sound.MAIN.stop();
//Sound.WIN.play();
next = new Button("Next Level");
this.add(next);
next.addActionListener(this);
next.setVisible(true);
revalidate();
repaint();
}
}
}
}
public void animate() {
anim.update(10);
hanim.update(50);
}
@Override
public void update(Graphics g) {
if (image == null) {
image = createImage(this.getWidth(), this.getHeight());
second = image.getGraphics();
}
second.setColor(getBackground());
second.fillRect(0, 0, getWidth(), getHeight());
second.setColor(getForeground());
paint(second);
g.drawImage(image, 0, 0, this);
}
@Override
public void paint(Graphics g) {
if (state == GameState.Running) {
g.drawImage(background, bg1.getBgX(), bg1.getBgY(), this);
g.drawImage(background, bg2.getBgX(), bg2.getBgY(), this);
paintTiles(g);
ArrayList projectiles = robot.getProjectiles();
for (int i = 0; i < projectiles.size(); i++) {
Projectile p = (Projectile) projectiles.get(i);
g.setColor(Color.BLUE);
g.fillRect(p.getX(), p.getY(), 10, 5);
}
g.drawImage(currentSprite, robot.getCenterX() - 61,
robot.getCenterY() - 63, this);
g.drawImage(hanim.getImage(), hb.getCenterX() - 48,
hb.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb2.getCenterX() - 48,
hb2.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb3.getCenterX() - 48,
hb3.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb4.getCenterX() - 48,
hb4.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb5.getCenterX() - 48,
hb5.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb6.getCenterX() - 48,
hb6.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb7.getCenterX() - 48,
hb7.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb8.getCenterX() - 48,
hb8.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb9.getCenterX() - 48,
hb9.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb10.getCenterX() - 48,
hb10.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb11.getCenterX() - 48,
hb11.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb12.getCenterX() - 48,
hb12.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb13.getCenterX() - 48,
hb13.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb14.getCenterX() - 48,
hb14.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb15.getCenterX() - 48,
hb15.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb16.getCenterX() - 48,
hb16.getCenterY() - 48, this);
g.setFont(font);
g.setColor(Color.WHITE);
g.drawString("Health: " + Integer.toString(rHealth), 5, 30);
g.drawString("Score: " + Integer.toString(score), 650, 30);
} else if (state == GameState.Dead) {
//setLayout(new FlowLayout());
g.setColor(Color.BLACK);
g.fillRect(0, 0, 800, 480);
g.setColor(Color.WHITE);
g.drawString("You're Dead!", 300, 200);
g.drawString("Score: " + score, 300, 250);
}
else if (state == GameState.Win) {
g.setColor(Color.BLACK);
g.fillRect(0, 0, 800, 480);
g.setColor(Color.WHITE);
g.drawString("You Beat this level!", 300, 200);
g.drawString("Score: " + score, 300, 250);
level++;
}
}
private void updateTiles() {
for (int i = 0; i < tilearray.size(); i++) {
Tile t = (Tile) tilearray.get(i);
t.update();
}
}
private void paintTiles(Graphics g) {
for (int i = 0; i < tilearray.size(); i++) {
Tile t = (Tile) tilearray.get(i);
g.drawImage(t.getTileImage(), t.getTileX(), t.getTileY(), this);
}
}
@Override
public void keyPressed(KeyEvent e) {
switch (e.getKeyCode()) {
case KeyEvent.VK_UP:
break;
case KeyEvent.VK_DOWN:
currentSprite = characterDown;
if (robot.isJumped() == false) {
robot.setDucked(true);
robot.setSpeedX(0);
}
break;
case KeyEvent.VK_LEFT:
robot.moveLeft();
robot.setMovingLeft(true);
break;
case KeyEvent.VK_RIGHT:
robot.moveRight();
robot.setMovingRight(true);
break;
case KeyEvent.VK_SPACE:
robot.jump();
break;
case KeyEvent.VK_CONTROL:
if (robot.isDucked() == false && robot.isJumped() == false
&& robot.isReadyToFire()) {
robot.shoot();
robot.setReadyToFire(false);
}
break;
}
}
@Override
public void keyReleased(KeyEvent e) {
switch (e.getKeyCode()) {
case KeyEvent.VK_UP:
break;
case KeyEvent.VK_DOWN:
currentSprite = anim.getImage();
robot.setDucked(false);
break;
case KeyEvent.VK_LEFT:
robot.stopLeft();
break;
case KeyEvent.VK_RIGHT:
robot.stopRight();
break;
case KeyEvent.VK_SPACE:
break;
case KeyEvent.VK_CONTROL:
robot.setReadyToFire(true);
Sound.GUN.play();
break;
}
}
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
public static Background getBg1() {
return bg1;
}
public static Background getBg2() {
return bg2;
}
public static Robot getRobot() {
return robot;
}
@Override
public void actionPerformed(ActionEvent evt) {
if (evt.getSource() == next)
level ++;
{
}
if (evt.getSource() == sOver)
level = 1;
{
}
}
}
我收到的错误消息是：
Exception in thread "AWT-EventQueue-1" java.lang.NullPointerException
at java.awt.Container.addImpl(Unknown Source)
at java.awt.Container.add(Unknown Source)
at androidGame.StartingClass.paint(StartingClass.java:372)
at androidGame.StartingClass.update(StartingClass.java:305)
at sun.awt.RepaintArea.updateComponent(Unknown Source)
at sun.awt.RepaintArea.paint(Unknown Source)
at sun.awt.windows.WComponentPeer.handleEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access0(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
this.add(sOver);
sOver = new Button("Start Over");
我想错误就在这里。在将它添加到小程序之前，您必须初始化 sOver。所以这样说：
sOver = new Button("Start Over");
this.add(sOver);
让我们看看它是否有效。
我想使用此代码向页面添加一个按钮，当游戏状态为 Dead 或 Win 时显示。此按钮将让用户重新开始或继续到下一个级别。我的动作侦听器尚未完全编码，因为我什至无法让按钮在页面上可见。我尝试使用
在按钮中编码setLayout(new FlowLayout());
this.add(sOver);
sOver = new Button("Start Over");
sOver.addActionListener(this);
但这会在游戏更改状态时导致错误。
package androidGame;
import java.applet.Applet;
import java.awt.event.*;
import java.applet.AudioClip;
import java.awt.Button;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Random;
import java.net.*;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.Clip;
import androidGame.framework.Animation;
import java.applet.Applet;
import java.applet.AudioClip;
import java.net.URL;
public class StartingClass extends Applet implements Runnable, KeyListener, ActionListener {
enum GameState {
Running, Dead, Win
}
GameState state = GameState.Running;
private static Robot robot;
public static Heliboy hb, hb2, hb3, hb4, hb5, hb6, hb7, hb8, hb9, hb10, hb11, hb12, hb13, hb14, hb15, hb16;
public static int score = 0;
public static int rHealth = 120;
private Font font = new Font(null, Font.BOLD, 30);
private Image image, currentSprite, character, character2, character3,
characterDown, characterJumped, background, heliboy, heliboy2,
heliboy3, heliboy4, heliboy5;
public static Image tilegrassTop, tilegrassBot, tilegrassLeft,
tilegrassRight, tiledirt, tilefire, tiledoor;
private Graphics second;
private URL base;
private static Background bg1, bg2;
private Animation anim, hanim;
int level = 1;
AudioClip clip;
Button next, sOver;
private ArrayList<Tile> tilearray = new ArrayList<Tile>();
@Override
public void init() {
setSize(800, 480);
setBackground(Color.BLACK);
setFocusable(true);
addKeyListener(this);
Frame frame = (Frame) this.getParent().getParent();
frame.setTitle("Robot Mania");
try {
base = getDocumentBase();
} catch (Exception e) {
// TODO: handle exception
}
// Image Setups
character = getImage(base, "data/character.png");
character2 = getImage(base, "data/character2.png");
character3 = getImage(base, "data/character3.png");
characterDown = getImage(base, "data/down.png");
characterJumped = getImage(base, "data/jumped.png");
heliboy = getImage(base, "data/heliboy.png");
heliboy2 = getImage(base, "data/heliboy2.png");
heliboy3 = getImage(base, "data/heliboy3.png");
heliboy4 = getImage(base, "data/heliboy4.png");
heliboy5 = getImage(base, "data/heliboy5.png");
background = getImage(base, "data/spacebackground.png");
tiledirt = getImage(base, "data/tiledirt.png");
tilegrassTop = getImage(base, "data/tilegrasstop.png");
tilegrassBot = getImage(base, "data/tilegrassbot.png");
tilegrassLeft = getImage(base, "data/tilegrassleft.png");
tilegrassRight = getImage(base, "data/tilegrassright.png");
tilefire = getImage(base, "data/tilefire.png");
tiledoor = getImage(base, "data/tiledoor.png");
anim = new Animation();
anim.addFrame(character, 1250);
anim.addFrame(character2, 50);
anim.addFrame(character3, 50);
anim.addFrame(character2, 50);
hanim = new Animation();
hanim.addFrame(heliboy, 100);
hanim.addFrame(heliboy2, 100);
hanim.addFrame(heliboy3, 100);
hanim.addFrame(heliboy4, 100);
hanim.addFrame(heliboy5, 100);
hanim.addFrame(heliboy4, 100);
hanim.addFrame(heliboy3, 100);
hanim.addFrame(heliboy2, 100);
currentSprite = anim.getImage();
}
@Override
public void start() {
//Sound.MAIN.loop();
bg1 = new Background(0, 0);
bg2 = new Background(2160, 0);
robot = new Robot();
// Initialize Tiles
try {
loadMap("data/map"+ level +".txt");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Random random = new Random();
int randomInt = random.nextInt(500);
hb = new Heliboy(700, 360);
hb2 = new Heliboy(900 + randomInt, 360);
hb3 = new Heliboy(2300 + randomInt, 360);
hb4 = new Heliboy(2900 + randomInt, 360);
hb5 = new Heliboy(3400 + randomInt, 360);
hb6 = new Heliboy(3900 + randomInt, 360);
hb7 = new Heliboy(4300 + randomInt, 360);
hb8 = new Heliboy(4700 + randomInt, 360);
hb9 = new Heliboy(5000 + randomInt, 360);
hb10 = new Heliboy(5300 + randomInt, 360);
hb11 = new Heliboy(5700 + randomInt, 360);
hb12 = new Heliboy(6000 + randomInt, 360);
hb13 = new Heliboy(6300 + randomInt, 360);
hb14 = new Heliboy(6700 + randomInt, 360);
hb15 = new Heliboy(7000 + randomInt, 360);
hb16 = new Heliboy(7200 + randomInt, 360);
Thread thread = new Thread(this);
thread.start();
}
private void loadMap(String filename) throws IOException {
ArrayList lines = new ArrayList();
int width = 0;
int height = 0;
BufferedReader reader = new BufferedReader(new FileReader(filename));
while (true) {
String line = reader.readLine();
// no more lines to read
if (line == null) {
reader.close();
break;
}
if (!line.startsWith("!")) {
lines.add(line);
width = Math.max(width, line.length());
}
}
height = lines.size();
for (int j = 0; j < 12; j++) {
String line = (String) lines.get(j);
for (int i = 0; i < width; i++) {
if (i < line.length()) {
char ch = line.charAt(i);
Tile t = new Tile(i, j, Character.getNumericValue(ch));
tilearray.add(t);
}
}
}
}
@Override
public void run() {
if (state == GameState.Running) {
while (true) {
robot.update();
if (robot.isJumped()) {
currentSprite = characterJumped;
} else if (robot.isJumped() == false
&& robot.isDucked() == false) {
currentSprite = anim.getImage();
}
ArrayList projectiles = robot.getProjectiles();
for (int i = 0; i < projectiles.size(); i++) {
Projectile p = (Projectile) projectiles.get(i);
if (p.isVisible() == true) {
p.update();
} else {
projectiles.remove(i);
}
}
updateTiles();
hb.update();
hb2.update();
hb3.update();
hb4.update();
hb5.update();
hb6.update();
hb7.update();
hb8.update();
hb9.update();
hb10.update();
hb11.update();
hb12.update();
hb13.update();
hb14.update();
hb15.update();
hb16.update();
bg1.update();
bg2.update();
animate();
repaint();
try {
Thread.sleep(17);
} catch (InterruptedException e) {
e.printStackTrace();
}
if (rHealth == 0) {
state = GameState.Dead;
Sound.MAIN.stop();
//Sound.DIE.play();
sOver = new Button("Start Over");
this.add(sOver);
sOver.addActionListener(this);
sOver.setVisible(true);
revalidate();
repaint();
}
if (robot.getCenterY() > 500) {
state = GameState.Dead;
Sound.MAIN.stop();
//Sound.DIE.play();
sOver = new Button("Start Over");
this.add(sOver);
sOver.addActionListener(this);
sOver.setVisible(true);
revalidate();
repaint();
}
if (score == 5){
state = GameState.Win;
Sound.MAIN.stop();
//Sound.WIN.play();
next = new Button("Next Level");
this.add(next);
next.addActionListener(this);
next.setVisible(true);
revalidate();
repaint();
}
}
}
}
public void animate() {
anim.update(10);
hanim.update(50);
}
@Override
public void update(Graphics g) {
if (image == null) {
image = createImage(this.getWidth(), this.getHeight());
second = image.getGraphics();
}
second.setColor(getBackground());
second.fillRect(0, 0, getWidth(), getHeight());
second.setColor(getForeground());
paint(second);
g.drawImage(image, 0, 0, this);
}
@Override
public void paint(Graphics g) {
if (state == GameState.Running) {
g.drawImage(background, bg1.getBgX(), bg1.getBgY(), this);
g.drawImage(background, bg2.getBgX(), bg2.getBgY(), this);
paintTiles(g);
ArrayList projectiles = robot.getProjectiles();
for (int i = 0; i < projectiles.size(); i++) {
Projectile p = (Projectile) projectiles.get(i);
g.setColor(Color.BLUE);
g.fillRect(p.getX(), p.getY(), 10, 5);
}
g.drawImage(currentSprite, robot.getCenterX() - 61,
robot.getCenterY() - 63, this);
g.drawImage(hanim.getImage(), hb.getCenterX() - 48,
hb.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb2.getCenterX() - 48,
hb2.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb3.getCenterX() - 48,
hb3.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb4.getCenterX() - 48,
hb4.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb5.getCenterX() - 48,
hb5.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb6.getCenterX() - 48,
hb6.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb7.getCenterX() - 48,
hb7.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb8.getCenterX() - 48,
hb8.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb9.getCenterX() - 48,
hb9.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb10.getCenterX() - 48,
hb10.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb11.getCenterX() - 48,
hb11.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb12.getCenterX() - 48,
hb12.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb13.getCenterX() - 48,
hb13.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb14.getCenterX() - 48,
hb14.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb15.getCenterX() - 48,
hb15.getCenterY() - 48, this);
g.drawImage(hanim.getImage(), hb16.getCenterX() - 48,
hb16.getCenterY() - 48, this);
g.setFont(font);
g.setColor(Color.WHITE);
g.drawString("Health: " + Integer.toString(rHealth), 5, 30);
g.drawString("Score: " + Integer.toString(score), 650, 30);
} else if (state == GameState.Dead) {
//setLayout(new FlowLayout());
g.setColor(Color.BLACK);
g.fillRect(0, 0, 800, 480);
g.setColor(Color.WHITE);
g.drawString("You're Dead!", 300, 200);
g.drawString("Score: " + score, 300, 250);
}
else if (state == GameState.Win) {
g.setColor(Color.BLACK);
g.fillRect(0, 0, 800, 480);
g.setColor(Color.WHITE);
g.drawString("You Beat this level!", 300, 200);
g.drawString("Score: " + score, 300, 250);
level++;
}
}
private void updateTiles() {
for (int i = 0; i < tilearray.size(); i++) {
Tile t = (Tile) tilearray.get(i);
t.update();
}
}
private void paintTiles(Graphics g) {
for (int i = 0; i < tilearray.size(); i++) {
Tile t = (Tile) tilearray.get(i);
g.drawImage(t.getTileImage(), t.getTileX(), t.getTileY(), this);
}
}
@Override
public void keyPressed(KeyEvent e) {
switch (e.getKeyCode()) {
case KeyEvent.VK_UP:
break;
case KeyEvent.VK_DOWN:
currentSprite = characterDown;
if (robot.isJumped() == false) {
robot.setDucked(true);
robot.setSpeedX(0);
}
break;
case KeyEvent.VK_LEFT:
robot.moveLeft();
robot.setMovingLeft(true);
break;
case KeyEvent.VK_RIGHT:
robot.moveRight();
robot.setMovingRight(true);
break;
case KeyEvent.VK_SPACE:
robot.jump();
break;
case KeyEvent.VK_CONTROL:
if (robot.isDucked() == false && robot.isJumped() == false
&& robot.isReadyToFire()) {
robot.shoot();
robot.setReadyToFire(false);
}
break;
}
}
@Override
public void keyReleased(KeyEvent e) {
switch (e.getKeyCode()) {
case KeyEvent.VK_UP:
break;
case KeyEvent.VK_DOWN:
currentSprite = anim.getImage();
robot.setDucked(false);
break;
case KeyEvent.VK_LEFT:
robot.stopLeft();
break;
case KeyEvent.VK_RIGHT:
robot.stopRight();
break;
case KeyEvent.VK_SPACE:
break;
case KeyEvent.VK_CONTROL:
robot.setReadyToFire(true);
Sound.GUN.play();
break;
}
}
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
public static Background getBg1() {
return bg1;
}
public static Background getBg2() {
return bg2;
}
public static Robot getRobot() {
return robot;
}
@Override
public void actionPerformed(ActionEvent evt) {
if (evt.getSource() == next)
level ++;
{
}
if (evt.getSource() == sOver)
level = 1;
{
}
}
}
我收到的错误消息是：
Exception in thread "AWT-EventQueue-1" java.lang.NullPointerException
at java.awt.Container.addImpl(Unknown Source)
at java.awt.Container.add(Unknown Source)
at androidGame.StartingClass.paint(StartingClass.java:372)
at androidGame.StartingClass.update(StartingClass.java:305)
at sun.awt.RepaintArea.updateComponent(Unknown Source)
at sun.awt.RepaintArea.paint(Unknown Source)
at sun.awt.windows.WComponentPeer.handleEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access0(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.awt.EventQueue.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
this.add(sOver);
sOver = new Button("Start Over");
我想错误就在这里。在将它添加到小程序之前，您必须初始化 sOver。所以这样说：
sOver = new Button("Start Over");
this.add(sOver);
让我们看看它是否有效。