JLayer - 暫停和恢復歌曲

Question

我注意到很多主題都是關於使用JLayer暫停/恢復MP3，所以為了幫助每個人，我已經完成了整個課程的設計！ 請參閱下面的答案。

注意：這僅供我個人使用，因此可能不像某些人希望的那樣強大。 但由於其簡單性，進行簡單的修改並不困難。

Answer 1

一個非常簡單的播放器實現，實際上暫停播放。 它的工作原理是使用一個單獨的線程來播放流並告訴玩家線程是否/何時暫停和恢復。

public class PausablePlayer {

    private final static int NOTSTARTED = 0;
    private final static int PLAYING = 1;
    private final static int PAUSED = 2;
    private final static int FINISHED = 3;

    // the player actually doing all the work
    private final Player player;

    // locking object used to communicate with player thread
    private final Object playerLock = new Object();

    // status variable what player thread is doing/supposed to do
    private int playerStatus = NOTSTARTED;

    public PausablePlayer(final InputStream inputStream) throws JavaLayerException {
        this.player = new Player(inputStream);
    }

    public PausablePlayer(final InputStream inputStream, final AudioDevice audioDevice) throws JavaLayerException {
        this.player = new Player(inputStream, audioDevice);
    }

    /**
     * Starts playback (resumes if paused)
     */
    public void play() throws JavaLayerException {
        synchronized (playerLock) {
            switch (playerStatus) {
                case NOTSTARTED:
                    final Runnable r = new Runnable() {
                        public void run() {
                            playInternal();
                        }
                    };
                    final Thread t = new Thread(r);
                    t.setDaemon(true);
                    t.setPriority(Thread.MAX_PRIORITY);
                    playerStatus = PLAYING;
                    t.start();
                    break;
                case PAUSED:
                    resume();
                    break;
                default:
                    break;
            }
        }
    }

    /**
     * Pauses playback. Returns true if new state is PAUSED.
     */
    public boolean pause() {
        synchronized (playerLock) {
            if (playerStatus == PLAYING) {
                playerStatus = PAUSED;
            }
            return playerStatus == PAUSED;
        }
    }

    /**
     * Resumes playback. Returns true if the new state is PLAYING.
     */
    public boolean resume() {
        synchronized (playerLock) {
            if (playerStatus == PAUSED) {
                playerStatus = PLAYING;
                playerLock.notifyAll();
            }
            return playerStatus == PLAYING;
        }
    }

    /**
     * Stops playback. If not playing, does nothing
     */
    public void stop() {
        synchronized (playerLock) {
            playerStatus = FINISHED;
            playerLock.notifyAll();
        }
    }

    private void playInternal() {
        while (playerStatus != FINISHED) {
            try {
                if (!player.play(1)) {
                    break;
                }
            } catch (final JavaLayerException e) {
                break;
            }
            // check if paused or terminated
            synchronized (playerLock) {
                while (playerStatus == PAUSED) {
                    try {
                        playerLock.wait();
                    } catch (final InterruptedException e) {
                        // terminate player
                        break;
                    }
                }
            }
        }
        close();
    }

    /**
     * Closes the player, regardless of current state.
     */
    public void close() {
        synchronized (playerLock) {
            playerStatus = FINISHED;
        }
        try {
            player.close();
        } catch (final Exception e) {
            // ignore, we are terminating anyway
        }
    }

    // demo how to use
    public static void main(String[] argv) {
        try {
            FileInputStream input = new FileInputStream("myfile.mp3"); 
            PausablePlayer player = new PausablePlayer(input);

            // start playing
            player.play();

            // after 5 secs, pause
            Thread.sleep(5000);
            player.pause();     

            // after 5 secs, resume
            Thread.sleep(5000);
            player.resume();
        } catch (final Exception e) {
            throw new RuntimeException(e);
        }
    }

}

Answer 2

import java.io.BufferedInputStream;
import java.io.FileInputStream;

import javax.swing.JOptionPane;

import javazoom.jl.player.Player;


public class CustomPlayer {

private Player player;
private FileInputStream FIS;
private BufferedInputStream BIS;
private boolean canResume;
private String path;
private int total;
private int stopped;
private boolean valid;

public CustomPlayer(){
    player = null;
    FIS = null;
    valid = false;
    BIS = null;
    path = null;
    total = 0;
    stopped = 0;
    canResume = false;
}

public boolean canResume(){
    return canResume;
}

public void setPath(String path){
    this.path = path;
}

public void pause(){
    try{
    stopped = FIS.available();
    player.close();
    FIS = null;
    BIS = null;
    player = null;
    if(valid) canResume = true;
    }catch(Exception e){

    }
}

public void resume(){
    if(!canResume) return;
    if(play(total-stopped)) canResume = false;
}

public boolean play(int pos){
    valid = true;
    canResume = false;
    try{
    FIS = new FileInputStream(path);
    total = FIS.available();
    if(pos > -1) FIS.skip(pos);
    BIS = new BufferedInputStream(FIS);
    player = new Player(BIS);
    new Thread(
            new Runnable(){
                public void run(){
                    try{
                        player.play();
                    }catch(Exception e){
                        JOptionPane.showMessageDialog(null, "Error playing mp3 file");
                        valid = false;
                    }
                }
            }
    ).start();
    }catch(Exception e){
        JOptionPane.showMessageDialog(null, "Error playing mp3 file");
        valid = false;
    }
    return valid;
}

}

並用於：

CustomPlayer player = new CustomPlayer();
player.setPath("MP3_FILE_PATH");
player.play(-1);

然后當你想暫停它時：

player.pause();

......並恢復它：

player.resume();

我希望我幫助了很多人。

Answer 3

雖然這個問題現在已有幾年了，但你應該注意到這個解決方案不適用於最新的JLayer版本和AdvancedPlayer ！

AdvancedPlayer - > public boolean play（int frames） - >條件

if(!ret) { .. } 

必須重新引入，否則播放一幀后播放將停止。

編輯：

似乎從Java 7開始，他們對daemonThreads的處理阻止了簡歷的工作。 只是刪除

t.setDaemon(true);

讓它再次工作！