Service后台服务控制音乐的播放暂停和停止,播放完自动播放下一曲

//添加获得sd卡的状态权限,和读取sd卡的权限
<uses-
permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<uses-
permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
//    MainActivity中用三个按钮,播放,暂停,停止,发送服务到后台服务来控制
public class MainActivity extends Activity implements OnClickListener {
private Button puase;
private Button stop;
private Button start;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
start = (Button) findViewById(R.id.start);
puase = (Button) findViewById(R.id.puase);
stop = (Button) findViewById(R.id.stop);

start.setOnClickListener(this);
puase.setOnClickListener(this);
stop.setOnClickListener(this);
}

@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, Service1.class);
switch (v.getId()) {
case R.id.start:
intent.putExtra("key", 1);
break;
case R.id.puase:
intent.putExtra("key", 2);
break;
case R.id.stop:
intent.putExtra("key", 3);
break;
default:
break;
}
startService(intent);
}
}
//自定义类,继承Service服务
public class Service1 extends Service {
private MediaPlayer mediaplayer;
private ArrayList<Music> list;
private String path = "";

4000
private int index = 0;

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

@Override
public void onCreate() {
super.onCreate();
mediaplayer = new MediaPlayer();
list = new ArrayList<Music>();
//读取SD卡
if (Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED)) {
File file = Environment.getExternalStorageDirectory();
path = file.getAbsolutePath();
}
list.add(new Music("男人歌", path + "/nanrenge.mp3"));
list.add(new Music("夜色", path + "/yese.mp3"));
list.add(new Music("漂洋过海来看你", path + "/piaoyang.mp3"));
list.add(new Music("兄弟无数", path + "/xiongdiwushu.mp3"));
//播放完成后自定播放下一曲
mediaplayer.setOnCompletionListener(new OnCompletionListener() {

@Override
public void onCompletion(MediaPlayer mp) {
index++;
play();
}
});
}
//用这个方法控制MainActivity发来的服务,控制音乐
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
int m = intent.getIntExtra("key", 0);
switch (m) {
case 1:
play();
break;
case 2:// 暂停
if (mediaplayer != null && mediaplayer.isPlaying())
mediaplayer.pause();
break;
case 3:// 停止
if (mediaplayer != null) {
mediaplayer.stop();
stopService(intent);
}
break;

default:
break;
}
return super.onStartCommand(intent, flags, startId);
}
//播放音乐
private void play() {
mediaplayer.reset();
try {
mediaplayer.setDataSource(list.get(index).getPath());
mediaplayer.prepare();
} catch (Exception e) {
e.printStackTrace();
}
mediaplayer.start();
}

@Override
public void onDestroy() {
super.onDestroy();
if (mediaplayer != null) {
mediaplayer.release();
mediaplayer = null;
}
}

}