首先获取SD卡path路径下的所有的MP3文件，并将文件名和文件大小存入List数组(此代码定义在FileUtils类中):
/**
* 读取目录中的Mp3文件的名字和大小
*/
public List<Mp3Info> getMp3Files(String path) {
SDCardRoot = Environment.getExternalStorageDirectory()
.getAbsolutePath(); //获取SD卡的路径名
List<Mp3Info> mp3Infos = new ArrayList<Mp3Info>();
File file = new File(SDCardRoot + File.separator + path);
File[] files = file.listFiles();
for (int i = 0; i < files.length; i++) {
if (files[i].getName().endsWith(".mp3")) {
Mp3Info mp3Info = new Mp3Info();
mp3Info.setMp3Name(files[i].getName());
mp3Info.setMp3Size(files[i].length() + "");
mp3Infos.add(mp3Info); //此mp3Info对象中包含mp3文件名和文件大小
}
}
return mp3Infos;
}
当前Activity继承自ListActivity，在此Activity的onResume方法中调用getMp3Files()方法，获取路径下的Mp3文件
@Override
protected void onResume() {
FileUtils fileUtils = new FileUtils();
mp3Infos = fileUtils.getMp3Files("mp3/");
List<HashMap<String,String>> list = new ArrayList<HashMap<String,String>>();
for(Iterator iterator = mp3Infos.iterator();iterator.hasNext();){
Mp3Info mp3Info = (Mp3Info) iterator.next();
HashMap<String,String> map = new HashMap<String,String>();
map.put("mp3_name", mp3Info.getMp3Name());
map.put("size_id", mp3Info.getMp3Size());
list.add(map);
}
SimpleAdapter simpleAdapter = new SimpleAdapter(this,list,R.layout.mp3info_item,new String[]{"mp3_name","size_id"},new int[] {R.id.mp3_name,R.id.size_id}); //mp3info_item.xml文件中仅有两个TextView，id为mp3_name和size_id
setListAdapter(simpleAdapter);
super.onResume();
}
当点击当前Activity中的某一行时，播放当前行的Mp3文件：
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
if(mp3Infos != null){
Mp3Info mp3Info = mp3Infos.get(position);
Intent intent = new Intent();
intent.putExtra("mp3Info", mp3Info);
intent.setClass(this,PlayerActivity.class);
startActivity(intent);
}
super.onListItemClick(l, v, position, id);
}
PlayerActivity.class类中通过Service来播放选中的Mp3文件，定义如下：
public class PlayerActivity extends Activity {
private ImageButton beginButton = null;
private ImageButton pauseButton = null;
private ImageButton stopButton = null;
private Mp3Info mp3Info = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
setContentView(R.layout.player);
super.onCreate(savedInstanceState);
Intent intent = getIntent();
mp3Info = (Mp3Info) intent.getSerializableExtra("mp3Info");
beginButton = (ImageButton) findViewById(R.id.begin);
pauseButton = (ImageButton) findViewById(R.id.pause);
stopButton = (ImageButton) findViewById(R.id.stop);
ButtonClickListener listener = new ButtonClickListener();
beginButton.setOnClickListener(listener);
pauseButton.setOnClickListener(listener);
stopButton.setOnClickListener(listener);
}
class ButtonClickListener implements OnClickListener {
@Override
public void onClick(View v) {
if (v.getId() == R.id.begin) { // 播放按键
//创建一个intent对象，通知Service开始播放MP3
Intent intent = new Intent();
intent.setClass(PlayerActivity.this, PlayerService.class);
intent.putExtra("mp3Info", mp3Info);
intent.putExtra("MSG", AppConstant.PlayerMsg.PLAY_MSG);
//启动Service
startService(intent);
} else if (v.getId() == R.id.pause) {
//通知Service暂停播放MP3
Intent intent = new Intent();
intent.setClass(PlayerActivity.this, PlayerService.class);
intent.putExtra("MSG", AppConstant.PlayerMsg.PAUSE_MSG);
startService(intent);
} else if (v.getId() == R.id.stop) {
//通知Service停止MP3文件
Intent intent = new Intent();
intent.setClass(PlayerActivity.this, PlayerService.class);
intent.putExtra("MSG", AppConstant.PlayerMsg.STOP_MSG);
startService(intent);
}
}
}
}
PlayerService定义如下:
public class PlayerService extends Service {
private boolean isPlaying = false;
private boolean isPause = false;
private boolean isReleased = false;
private MediaPlayer mediaPlayer = null;
private Mp3Info mp3Info = null;
private ArrayList<Queue> queues = null;
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
// 每次从Activity向Service发送intent对象时，触发该事件
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
mp3Info = (Mp3Info) intent.getSerializableExtra("mp3Info");
int MSG = intent.getIntExtra("MSG", 0);
if (mp3Info != null) {
if (MSG == AppConstant.PlayerMsg.PLAY_MSG) {
play(mp3Info);
}
}
else{
if(MSG == AppConstant.PlayerMsg.PAUSE_MSG){
pause();
}
else if(MSG == AppConstant.PlayerMsg.STOP_MSG){
stop();
}
}
return super.onStartCommand(intent, flags, startId);
}
private void play(Mp3Info mp3Info){
if(!isPlaying){
String path = getMp3Path(mp3Info);
mediaPlayer = MediaPlayer.create(this, Uri.parse("file://" + path));
mediaPlayer.setLooping(true); //设置歌曲循环播放
mediaPlayer.start();
isPlaying = true;
isReleased = false;
}
}
private void pause(){
if(mediaPlayer != null){
if(isPlaying){
mediaPlayer.pause();
} else{
mediaPlayer.start();
}
isPlaying = isPlaying ? false : true;
}
}
private void stop(){
if(mediaPlayer!=null){
if(isPlaying){
if(!isReleased){
mediaPlayer.stop();
mediaPlayer.release();
isReleased = true;
isPlaying = false;
}
}
}
}
private String getMp3Path(Mp3Info mp3Info){
String SDCardRoot = Environment.getExternalStorageDirectory().getAbsolutePath();
String path = SDCardRoot + File.separator + "mp3" + File.separator + mp3Info.getMp3Name();
return path;
}