public class MainActivity extends AppCompatActivity implements View.OnClickListener{

 private ImageButton mStart;
 private ImageButton mStop;
 private TextView mMusicName;
 private TextView mSongerName;
 private ActivityReceiver mActivityReceiver;
 public static final String CTL_ACTION = "com.trampcr.action.CTL_ACTION";
 public static final String UPDATE_ACTION = "com.trampcr.action.UPDATE_ACTION";

 //定義音樂播放狀態(tài)，0x11代表沒有播放，0x12代表正在播放，0x13代表暫停
 int status = 0x11;
 String[] musicNames = new String[]{"完美生活", "那一年", "故鄉(xiāng)"};
 String[] songerNames = new String[]{"許巍", "許巍", "許巍"};


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

  mStart = (ImageButton) findViewById(R.id.start);
  mStop = (ImageButton) findViewById(R.id.stop);
  mMusicName = (TextView) findViewById(R.id.music_name);
  mSongerName = (TextView) findViewById(R.id.songer_name);

  mStart.setOnClickListener(this);
  mStop.setOnClickListener(this);

  mActivityReceiver = new ActivityReceiver();
  //創(chuàng)建IntentFilter
  IntentFilter filter = new IntentFilter();
  //指定BroadcastReceiver監(jiān)聽的Action
  filter.addAction(UPDATE_ACTION);
  //注冊BroadcastReceiver
  registerReceiver(mActivityReceiver, filter);

  Intent intent = new Intent(MainActivity.this, MusicService.class);
  //啟動后臺Service
  startService(intent);
 }

 public class ActivityReceiver extends BroadcastReceiver {
  @Override
  public void onReceive(Context context, Intent intent) {
   //獲取Intent中的update消息，update代表播放狀態(tài)
   int update = intent.getIntExtra("update", -1);
   //獲取Intent中的current消息，current代表當前正在播放的歌曲
   int current = intent.getIntExtra("current", -1);
   if (current >= 0){
    mMusicName.setText(musicNames[current]);
    mSongerName.setText(songerNames[current]);
   }
   switch (update){
    case 0x11:
     mStart.setBackgroundResource(R.drawable.play);
     status = 0x11;
     break;
    //控制系統(tǒng)進入播放狀態(tài)
    case 0x12:
     //在播放狀態(tài)下設(shè)置使用暫停圖標
     mStart.setBackgroundResource(R.drawable.pause);
     status = 0x12;
     break;
    case 0x13:
     //在暫停狀態(tài)下設(shè)置使用播放圖標
     mStart.setBackgroundResource(R.drawable.play);
     status = 0x13;
     break;
   }
  }
 }

 @Override
 public void onClick(View v) {
  Intent intent = new Intent(CTL_ACTION);
  switch (v.getId()){
   case R.id.start:
    intent.putExtra("control", 1);
    break;
   case R.id.stop:
    intent.putExtra("control", 2);
    break;
  }
  //發(fā)送廣播，將被Service中的BroadcastReceiver接收到
  sendBroadcast(intent);
 }
}

public class MusicService extends Service {

 MyReceiver serviceReceiver;
 AssetManager mAssetManager;
 String[] musics = new String[]{"prefectLife.mp3", "thatYear.mp3", "country.mp3"};
 MediaPlayer mMediaPlayer;
 int status = 0x11;
 int current = 0; // 記錄當前正在播放的音樂

 @Nullable
 @Override
 public IBinder onBind(Intent intent) {
  return null;
 }

 @Override
 public void onCreate() {
  super.onCreate();
  mAssetManager = getAssets();
  serviceReceiver = new MyReceiver();
  //創(chuàng)建IntentFilter
  IntentFilter filter = new IntentFilter();
  filter.addAction(MainActivity.CTL_ACTION);
  registerReceiver(serviceReceiver, filter);
  //創(chuàng)建MediaPlayer
  mMediaPlayer = new MediaPlayer();
  //為MediaPlayer播放完成事件綁定監(jiān)聽器
  mMediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
   @Override
   public void onCompletion(MediaPlayer mp) {
    current++;
    if (current >= 3) {
     current = 0;
    }
    //發(fā)送廣播通知Activity更改文本框
    Intent sendIntent = new Intent(MainActivity.UPDATE_ACTION);
    sendIntent.putExtra("current", current);
    //發(fā)送廣播，將被Activity中的BroadcastReceiver接收到
    sendBroadcast(sendIntent);
    //準備并播放音樂
    prepareAndPlay(musics[current]);
   }
  });
 }

 public class MyReceiver extends BroadcastReceiver {
  @Override
  public void onReceive(Context context, Intent intent) {
   int control = intent.getIntExtra("control", -1);
   switch (control){
    case 1: // 播放或暫停
     //原來處于沒有播放狀態(tài)
     if (status ==0x11){
      //準備播放音樂
      prepareAndPlay(musics[current]);
      status = 0x12;
     }
     //原來處于播放狀態(tài)
     else if (status == 0x12){
      //暫停
      mMediaPlayer.pause();
      status = 0x13; // 改變?yōu)闀和顟B(tài)
     }
     //原來處于暫停狀態(tài)
     else if (status == 0x13){
      //播放
      mMediaPlayer.start();
      status = 0x12; // 改變狀態(tài)
     }
     break;
    //停止聲音
    case 2:
     //如果原來正在播放或暫停
     if (status == 0x12 || status == 0x13){
      //停止播放
      mMediaPlayer.stop();
      status = 0x11;
     }
   }
   //廣播通知Activity更改圖標、文本框
   Intent sendIntent = new Intent(MainActivity.UPDATE_ACTION);
   sendIntent.putExtra("update", status);
   sendIntent.putExtra("current", current);
   //發(fā)送廣播，將被Activity中的BroadcastReceiver接收到
   sendBroadcast(sendIntent);
  }
 }

 private void prepareAndPlay(String music) {
  try {
   //打開指定的音樂文件
   AssetFileDescriptor assetFileDescriptor = mAssetManager.openFd(music);
   mMediaPlayer.reset();
   //使用MediaPlayer加載指定的聲音文件
   mMediaPlayer.setDataSource(assetFileDescriptor.getFileDescriptor(), assetFileDescriptor.getStartOffset(), assetFileDescriptor.getLength());
   mMediaPlayer.prepare(); // 準備聲音
   mMediaPlayer.start(); // 播放
  } catch (IOException e) {
   e.printStackTrace();
  }
 }
}