我正在 Android 中创建音乐播放器。播放歌曲时出现问题：不知道是我的逻辑问题还是我的Service Class的实现问题。
问题是当我单击 ListView 项目时，歌曲会播放，但当我再次单击它时，歌曲会再次播放。我按多少次ListViewItem就会同时播放多少首歌曲。
这是我的代码：
播放列表活动.java
public class PlayListActivity extends ListActivity {
public ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();
private ServiceConnection serviceConnection = new AudioPlayerServiceConnection();
private MusicService audioPlayer;
private Intent audioPlayerIntent;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.playlist);
audioPlayerIntent = new Intent(this, MusicService.class);
bindService(audioPlayerIntent, serviceConnection, Context.BIND_AUTO_CREATE);
ArrayList<HashMap<String, String>> songsListData = new ArrayList<HashMap<String, String>>();
SongManager plm = new SongManager();
this.songsList = plm.getPlayList(this);
for (int i = 0; i < songsList.size(); i++) {
HashMap<String, String> song = songsList.get(i);
songsListData.add(song);
}// end loop
ListAdapter adapter = new SimpleAdapter(this, songsListData,
R.layout.playlist_item, new String[] { "songTitle","songArtist"}, new int[] {
R.id.songTitle, R.id.songArtist });
setListAdapter(adapter);
ListView lv = getListView();
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
int songIndex = position;
playSongSong(songIndex);
//finish();
}
});
}
public void playSongSong(int song){
Intent intent = new Intent(MusicService.PLAY_TRACK);
intent.putExtra("songIndex", song);
this.sendBroadcast(intent);
}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
unbindService(serviceConnection);
super.onDestroy();
}
private final class AudioPlayerServiceConnection implements ServiceConnection {
public void onServiceConnected(ComponentName className, IBinder baBinder) {
audioPlayer = ((MusicService.AudioPlayerBinder) baBinder).getService();
startService(audioPlayerIntent);
}
public void onServiceDisconnected(ComponentName className) {
audioPlayer = null;
}
}}
音乐服务.java
public class MusicService extends Service implements OnCompletionListener {
public static final String INTENT_BASE_NAME = "com.example.serviceaudio.MusicService";
public static final String PLAY_TRACK = INTENT_BASE_NAME + ".PLAY_TRACK";
private ArrayList<HashMap<String, String >> songList = new ArrayList<HashMap<String, String>>();
private SongManager songManager = new SongManager();
private MediaPlayer mp;
private AudioPlayerBroadcastReceiver broadcastReceiver = new AudioPlayerBroadcastReceiver();
private final String TAG = "MusicService";
public class AudioPlayerBinder extends Binder {
public MusicService getService() {
Log.v(TAG, "AudioPlayerBinder: getService() called");
return MusicService.this;
}
}
private final IBinder audioPlayerBinder = new AudioPlayerBinder();
@Override
public IBinder onBind(Intent intent) {
Log.v(TAG, "AudioPlayer: onBind() called");
return audioPlayerBinder;
}
@Override
public void onCreate() {
Log.v(TAG, "AudioPlayer: onCreate() called");
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(PLAY_TRACK);
registerReceiver(broadcastReceiver, intentFilter);
songList = songManager.getPlayList(this);
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// TODO Auto-generated method stub
return super.onStartCommand(intent, flags, startId);
}
@Override
public void onDestroy() {
Log.i(TAG, "AudioPlayer: onDestroy() called");
}
@Override
public void onLowMemory() {
stopSelf();
}
public void onCompletion(MediaPlayer _mediaPlayer) {
}
private void playSong(int songIndex){
try {
mp = new MediaPlayer();
mp.reset();
mp.setDataSource(songList.get(songIndex).get("songPath"));
mp.prepare();
mp.start();
// Displaying Song title
String songTitle = songList.get(songIndex).get("songTitle"); updateProgressBar();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
private class AudioPlayerBroadcastReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
int currentSongIndex = intent.getExtras().getInt("songIndex");
Log.d(TAG, "Received intent for action " + intent.getAction() + " for id: " + currentSongIndex);
if( PLAY_TRACK.equals(action)) {
playSong(currentSongIndex);
}
}
}
}