问题描述
我正在用 Java 编写一个程序，每次用户按下键盘上的按钮时，都会播放一首歌曲。但是，当我对此进行测试时，按下按键会使歌曲相互重叠播放，而不是在播放另一首歌曲之前停止播放。 这是我在播放器中的代码：
import javax.swing.*;
import javax.sound.sampled.*;
import java.io.*;
public class Player
{
public void playmusic(String musicfile) {
File soundFile = new File(musicfile);
try {
Clip clip = AudioSystem.getClip();
if(musicfile.equals("stop")){
clip.stop();
}
else {
AudioInputStream inputStream= AudioSystem.getAudioInputStream(soundFile);
clip.open(inputStream);
//clip.loop(clip.LOOP_CONTINUOUSLY);
clip.start();
}
}
catch(Exception e)
{
System.out.println(e);
}
}
}
在我的 Game 类中，我创建了一个名为 play 的 Player 类的实例。这是类（与音乐相关的方法是 keypressed()）：
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.event.*;
public class Game extends JPanel implements Runnable,KeyListener{
private BufferedImage back;
private int key;
private String[] song;
private Player play;
private ImageIcon menu,choose;
private String screen;
public Game() {
new Thread(this).start();
this.addKeyListener(this);
key =-1;
play = new Player();
song = new String[]{"the_greatest_show.wav","a_million_dreams.wav","a_million_dreams_reprise.wav","come_alive.wav","the_other_side.wav","never_enough.wav","this_is_me.wav","rewrite_the_star.wav","tightrope.wav","never_enough_reprise.wav","from_Now_on.wav"};
letter = 'Z';
menu = new ImageIcon("menu.png");
choose = new ImageIcon("select.png");
screen = "Menu";
}
public void run()
{
try
{
while(true)
{
Thread.currentThread().sleep(5);
repaint();
}
}
catch(Exception e)
{
}
}
public void paint(Graphics g){
Graphics2D twoDgraph = (Graphics2D) g;
if( back ==null)
back=(BufferedImage)( (createImage(getWidth(),getHeight())));
Graphics g2d = back.createGraphics();
g2d.clearRect(0,getSize().width,getSize().height);
switch(screen){
case("Menu"):
g2d.drawImage(menu.getimage(),1000,700,this);
break;
case("Choose"):
g2d.drawImage(choose.getimage(),this);
}
twoDgraph.drawImage(back,null,0);
}
public void stopMusic(){
play.playmusic("stop");
}
@Override
public void keyTyped(KeyEvent e) {
// Todo Auto-generated method stub
}
@Override
public void keypressed(KeyEvent e) {
// Todo Auto-generated method stub
key= e.getKeyCode();
char c = (char)(key);
switch(c){
case 'A':
stopMusic();
play.playmusic(song[0]);
break;
case 'S':
stopMusic();
play.playmusic(song[1]);
break;
case 'D':
stopMusic();
play.playmusic(song[2]);
break;
case 'F':
stopMusic();
play.playmusic(song[3]);
break;
case 'G':
stopMusic();
play.playmusic(song[4]);
break;
case 'H':
stopMusic();
play.playmusic(song[5]);
break;
case 'J':
stopMusic();
play.playmusic(song[6]);
break;
case 'K':
stopMusic();
play.playmusic(song[7]);
break;
case 'L':
stopMusic();
play.playmusic(song[8]);
break;
case 'V':
stopMusic();
play.playmusic(song[9]);
break;
case 'B':
stopMusic();
play.playmusic(song[10]);
break;
default:
stopMusic();
}
}
@Override
public void keyreleased(KeyEvent e) {
}
}
请帮我解决这个问题。提前致谢。
解决方法
如果您在方法内调用 getClip()，您将停止第二个剪辑，因为您丢失了对前一个剪辑的引用（并且将继续在后台播放）。 AudioSystem.getClip() 返回一个新剪辑，而不是当前剪辑。
当您播放下一首歌曲时，您会同时播放两个片段：第一个片段和当前片段，因为您停止的那个片段是一个全新的片段。
Clip[0] Clip[1] Clip[2]
Song 1 (nosong-stopped) Song 2
为了解决这个问题，你可以让 clip 成为一个全局变量，所以当 stop() 和 close() 被调用时，当前歌曲的 clip 是被选择的（你将只有一个剪辑）。
Clip clip = null;
//...
public void playmusic(String musicfile) {
File soundFile = new File(musicfile);
try
{
if(musicfile.equals("stop"))
{
if (clip!=null) //do not nest it to the previous condition ...
{
clip.stop();
clip.flush();
clip.close();
}
}
else //...so no song is played if you called stop and clip was null
{
AudioInputStream inputStream= AudioSystem.getAudioInputStream(soundFile);
if (clip == null || !clip.isOpen())
clip = AudioSystem.getClip();
clip.open(inputStream);
//clip.loop(clip.LOOP_CONTINUOUSLY);
clip.start();
}
}
catch(Exception e)
{
System.out.println(e);
}
}
替换 playmusic() 方法并检查
public void playmusic(String musicfile) {
try {
Clip clip = AudioSystem.getClip();
if(musicfile.equals("stop")){
clip.stop();
}
else {
File soundFile = new File(musicfile);
AudioInputStream inputStream= AudioSystem.getAudioInputStream(soundFile);
clip.open(inputStream);
//clip.loop(clip.LOOP_CONTINUOUSLY);
clip.start();
}
}
catch(Exception e)
{
System.out.println(e);
}
}