android音乐播放器实现（Service+BroadcastReceiver+Notification）

public interface IMusic {
public void moveon();//继续
public void pause();//暂停
public void stop();//停止
public void nextSong();//下一曲
public void lastSong();//上一曲
}

public class Mp3Application extends Application {
public List<Song> songsList;//当前播放列表
public int songItemPos;//当前播放音乐在列表中的位置
public NotificationManager notManager;
public IMusic music;
}

定义Service类，用于控制音乐播放：
public class PlayerService extends Service {
private MediaPlayer mp;
private Mp3Application application;
private List<Song> songs;
private int songItemPos;

@Override
public void onCreate() {
super.onCreate();
application = (Mp3Application) getApplication();
songs = application.songsList;
}

@Override
public IBinder onBind(Intent intent) {
play(songItemPos);
return new MusicListener();
}

public void play(int position) {
<span style="white-space:pre">        </span>//传入播放位置在列表中的边界
if(position>=0){
position=position % application.songsList.size();
}
else{
position = application.songsList.size()+ position;
}

application.songItemPos = position;//在全局变量中标记当前播放位置
Song currentSong = songs.get(position);//获取当前播放音乐
Uri musicTableForSD = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
Uri uri = Uri.withAppendedPath(musicTableForSD,
"/" + currentSong.getId());//初始化mp对象
mp = MediaPlayer.create(this, uri);

System.out.println(currentSong.getName());

try {
mp.start();

} catch (Exception e) {
e.printStackTrace();
}
}

@Override
public boolean onUnbind(Intent intent) {
mp.stop();
mp.release();
mp = null;
return super.onUnbind(intent);
}

@Override
public void onDestroy() {
super.onDestroy();
}
<span style="white-space:pre">    </span>//实现IMusic接口，用于接收播放信息
private class MusicListener extends Binder implements IMusic {

@Override
public void moveon() {
if (mp != null) {
mp.start();
}
}

@Override
public void pause() {
if (mp != null) {
mp.pause();
}
}

@Override
public void stop() {
if (mp != null) {
mp.stop();
mp.release();
mp = null;
}
}

@Override
public void nextSong() {
if (mp != null) {
mp.stop();
play(++application.songItemPos);
}
}

@Override
public void lastSong() {
if (mp != null) {
mp.stop();
play(--application.songItemPos);
}
}
}

}

public class MainActivity extends Activity {
.....
private RemoteViews contentView;

private Notification notification;
private Mp3Application application;
private IMusic music;
.....

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

......

// 初始化通知栏播放控件
initNotificationBar();

......
}

public void initNotificationBar() {
notification = new Notification();
//初始化通知
notification.icon = R.drawable.ic_launcher;
contentView = new RemoteViews(getPackageName(),
R.layout.notification_control);
notification.contentView = contentView;

Intent intentPlay = new Intent("play");//新建意图，并设置action标记为"play"，用于接收广播时过滤意图信息
PendingIntent pIntentPlay = PendingIntent.getBroadcast(this, 0,
intentPlay, 0);
contentView.setOnClickPendingIntent(R.id.bt_notic_play, pIntentPlay);//为play控件注册事件

Intent intentPause = new Intent("pause");
PendingIntent pIntentPause = PendingIntent.getBroadcast(this, 0,
intentPause, 0);
contentView.setOnClickPendingIntent(R.id.bt_notic_pause, pIntentPause);

Intent intentNext = new Intent("next");
PendingIntent pIntentNext = PendingIntent.getBroadcast(this, 0,
intentNext, 0);
contentView.setOnClickPendingIntent(R.id.bt_notic_next, pIntentNext);

Intent intentLast = new Intent("last");
PendingIntent pIntentLast = PendingIntent.getBroadcast(this, 0,
intentLast, 0);
contentView.setOnClickPendingIntent(R.id.bt_notic_last, pIntentLast);

Intent intentCancel = new Intent("cancel");
PendingIntent pIntentCancel = PendingIntent.getBroadcast(this, 0,
intentCancel, 0);
contentView
.setOnClickPendingIntent(R.id.bt_notic_cancel, pIntentCancel);
notification.flags = notification.FLAG_NO_CLEAR;//设置通知点击或滑动时不被清除
application.notManager.notify(Const.NOTI_CTRL_ID, notification);//开启通知

}

}
定义BroadcastReceiver类，用于接收来自Notification的广播并控制音乐播放：

public class Mp3Receiver extends BroadcastReceiver {
private Mp3Application application;
private IMusic music;

@Override
public void onReceive(Context context, Intent intent) {

application = (Mp3Application) context.getApplicationContext();
String ctrl_code = intent.getAction();//获取action标记，用户区分点击事件

music = application.music;//获取全局播放控制对象，该对象已在Activity中初始化
if (music != null) {
if ("play".equals(ctrl_code)) {
music.moveon();
System.out.println("play");
} else if ("pause".equals(ctrl_code)) {
music.pause();
System.out.println("pause");
} else if ("next".equals(ctrl_code)) {
music.nextSong();
System.out.println("next");
} else if ("last".equals(ctrl_code)) {
music.lastSong();
System.out.println("last");
}
}

if ("cancel".equals(ctrl_code)) {
application.notManager.cancel(Const.NOTI_CTRL_ID);
System.exit(0);
}
}

}

最后别忘了在清单文件中声明广播类并定制广播哦：
<application
android:name="com.cxc.Mp3Player.util.Mp3Application"
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<uses-library android:name="android.test.runner" >
</uses-library>

......

<receiver
android:name="com.cxc.Mp3Player.receiver.Mp3Receiver"
android:exported="true" >
<intent-filter>
<action android:name="play" /><!-- 定制play广播 -->
<action android:name="last" /><!-- 定制last广播 -->
<action android:name="next" /><!-- ...... -->
<action android:name="pause" />
<action android:name="cancel" />
</intent-filter>
</receiver>
</application>