我最近开始用 Java 编码,并决定尝试制作游戏 我从 2D 平台游戏开始,在网上找到了一些音频 .java 文件并将它们添加到
但是当我运行游戏时,我得到一个 NullPointerException ,这真的让我很恼火,为什么它不起作用
这是我的音频文件代码:
package me.EuanGraphics.Audio;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.Clip;
public class AudioPlayer {
private Clip clip;
public AudioPlayer(String s) {
try {
AudioInputStream ais =
AudioSystem.getAudioInputStream(
getClass().getResourceAsStream(s)
);
AudioFormat baseFormat = ais.getFormat();
AudioFormat decodeFormat = new AudioFormat (
AudioFormat.Encoding.PCM_SIGNED,
baseFormat.getSampleRate(),
16,
baseFormat.getChannels(),
baseFormat.getChannels() * 2,
baseFormat.getSampleRate(), false
);
AudioInputStream dais =
AudioSystem.getAudioInputStream(
decodeFormat, ais);
clip = AudioSystem.getClip();
clip.open(dais);
}
catch(Exception e) {
e.printStackTrace();
}
}
public void play() {
if(clip == null) return;
stop();
clip.setFramePosition(0);
clip.start();
}
public void stop() {
if (clip.isRunning()) clip.stop();
}
public void close() {
stop();
clip.close();
}
}
这是我游戏中的菜单状态,用于在您做出选择时调用音频文件并播放它
package me.EuanGraphics.GameState;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import me.EuanGraphics.Entity.PlayerSave;
import me.EuanGraphics.Handler.Keys;
import me.EuanGraphics.Tilemap.Background;
import me.EuanGraphics.Audio.AudioPlayer;
public class MenuState extends GameState {
private BufferedImage head;
private Background menubg;
private AudioPlayer menuoption;
private AudioPlayer menuselect;
private int currentChoice = 0;
private String[] options = {
"Start",
"Quit"
};
private Color titleColor;
private Font titleFont;
private Font font;
private Font font2;
public MenuState(GameStateManager gsm) {
super(gsm);
try {
//Load float head
head = ImageIO.read(getClass().getResourceAsStream("/HUD/Hud.gif")).getSubimage(0, 12, 12, 11);
menubg = new Background("/Backgrounds/Menu.png", 0);
//Titles and fonts
titleColor = Color.BLACK;
titleFont = new Font("Time New Roman", Font.PLAIN, 20);
font = new Font("Arial", Font.PLAIN, 14);
font2 = new Font("Arial", Font.PLAIN, 10);
}
catch(Exception e) {
e.printStackTrace();
}
}
public void init() {
menuoption = new AudioPlayer("/SFX/menuoption.wav");
menuselect = new AudioPlayer("/SFX/menuselect.mp3");
}
public void update() {
//Check Keys
handleInput();
}
public void draw(Graphics2D g) {
//Draw Background
menubg.draw(g);
// Draw Title
g.setColor(titleColor);
g.setFont(titleFont);
g.drawString("Dragontale: Remastered", 55, 90);
// Draw Menu Options
g.setFont(font);
g.setColor(Color.BLACK);
g.drawString("Start", 145, 165);
g.drawString("Quit", 145, 185);
// Draw Floating Heads
if(currentChoice == 0) g.drawImage(head, 125, 154, null);
else if(currentChoice == 1) g.drawImage(head, 125, 174, null);
//Other
g.setFont(font2);
g.drawString("2015 Euan P.", 10, 232);
}
private void select() {
if(currentChoice == 0) {
PlayerSave.init();
}
else if(currentChoice == 1) {
System.exit(0);
}
}
@Override
public void handleInput() {
if(Keys.isPressed(Keys.ENTER)) select();
if(Keys.isPressed(Keys.UP)) {
if(currentChoice > 0) {
menuoption.play();
currentChoice--;
}
}
if(Keys.isPressed(Keys.DOWN)) {
if(currentChoice < options.length - 1) {
menuoption.play();
currentChoice++;
}
}
}
}
在我告诉代码播放音频文件的地方出现错误 例如menuoption.play()
谢谢 - 尤安
最佳答案
当应用程序在需要对象的情况下尝试使用 null 时,会发生 NullPointerException。
也许在这里可以做点什么:
public void play() {
if(clip == null) return;
stop();
clip.setFramePosition(0);
clip.start(); }
http://docs.oracle.com/javase/7/docs/api/java/lang/NullPointerException.html
关于java - NullPointerException - 音频 - 2D java 平台游戏,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/29463525/