如何使用javax.sound.sampled.LineListener？

warherolion：

我有一个程序，会问他们想要的歌曲，可播放歌曲列表出来，用户可以选择一个曾经歌曲结束后它会询问他们要再次播放哪首歌曲的用户的用户。我被告知要使用的线路监听器这一点，但我似乎无法如何，即使使用了Oracle文档之后，要弄清楚

我的代码

public class Main {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
String[] pathnames;
File MusicFileChosen;
String musicDir;
boolean songComplete = false;

pathnames = ProgramMap.musicDir.list();

// Print the names of files and directories
for (int ListNum = 0; ListNum < pathnames.length; ListNum++) {
    System.out.println(ListNum + 1 + ". " + pathnames[ListNum]);
}


for (int playlistLength = 0; playlistLength < pathnames.length; playlistLength++){
    if (!songComplete) {
        System.out.println("Which Song would you like to play?");
        int musicChoice = input.nextInt();
        musicDir = ProgramMap.userDir + "\\src\\Music\\" + pathnames[musicChoice - 1];
        MusicFileChosen = new File(musicDir);
        PlaySound(MusicFileChosen, pathnames[musicChoice - 1]);

    }
}
}
public static void PlaySound(File sound, String FileName){
try{
    // Inits the Audio System
    Clip clip = AudioSystem.getClip();

    AudioInputStream AudioInput = AudioSystem.getAudioInputStream(sound);

    //Finds and accesses the clip
    clip.open(AudioInput);

    //Starts the clip
    clip.start();

    System.out.println("Now Playing " + FileName);

    clip.drain();


}catch (Exception e){
    System.out.println("Error playing music");
}

}}

严：

基本上一件事，你需要改变是更换这样的：

for (int playlistLength = 0; playlistLength < pathnames.length; playlistLength++){

喜欢的东西：

while (true) {
    System.out.println("Which Song would you like to play?");
    int musicChoice = input.nextInt();
    musicDir = ProgramMap.userDir + "\\src\\Music\\" + pathnames[musicChoice - 1];
    MusicFileChosen = new File(musicDir);
    PlaySound(MusicFileChosen, pathnames[musicChoice - 1]);
}

您可以添加一些逻辑来打破循环。

另外，我建议改变一点点的PlaySound方法：

    public static void PlaySound(File sound, String FileName) {
        try (final AudioInputStream in = getAudioInputStream(sound)) {

            final AudioFormat outFormat = getOutFormat(in.getFormat());
            Info info = new Info(SourceDataLine.class, outFormat);

            try (final SourceDataLine line =
                         (SourceDataLine) AudioSystem.getLine(info)) {

                if (line != null) {
                    line.open(outFormat);
                    line.start();
                    System.out.println("Now Playing " + FileName);
                    stream(getAudioInputStream(outFormat, in), line);
                    line.drain();
                    line.stop();
                }
            }

        } catch (UnsupportedAudioFileException
                | LineUnavailableException
                | IOException e) {
            System.err.println("Error playing music\n" + e.getMessage());
        }
    }

    private static AudioFormat getOutFormat(AudioFormat inFormat) {
        final int ch = inFormat.getChannels();
        final float rate = inFormat.getSampleRate();
        return new AudioFormat(PCM_SIGNED, rate, 16, ch, ch * 2, rate, false);
    }

    private static void stream(AudioInputStream in, SourceDataLine line)
            throws IOException {
        final byte[] buffer = new byte[4096];
        for (int n = 0; n != -1; n = in.read(buffer, 0, buffer.length)) {
            line.write(buffer, 0, n);
        }
    }

它需要播放MP3，因为你可以面对这样的问题：未知帧大小。

要添加MP3读取支持Java声音，在JMF的mp3plugin.jar添加到应用程序的运行时类路径。https://www.oracle.com/technetwork/java/javase/download-137625.html

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