更改轨道媒体播放器android答案

【问题标题】：changing a track media player android更改轨道媒体播放器android
【发布时间】：2012-08-31 11:47:06
【问题描述】：

我目前正在使用 MediaPlayer 播放一首可以正常播放的歌曲。在用户选择不同的歌曲时，我正在尝试播放。但是，MediaPlayer 收到错误（1，-2147483648）和错误（1，-2147483648）。这些日志在调用 prepareASync() 后打印；注意：文件的路径看起来是正确的。但是，如何检查有效的文件路径？

顺序如下：

           mPlayer.reset();
           Log.d(TAG,"after reset");
           mPlayer.setDataSource(mTrackToBePlayed);
           Log.d(TAG,"after setDataSource");
          // mPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
           mPlayer.setOnPreparedListener(preparedListener);
           Log.d(TAG,"after setOnPreparedListener");
           mPlayer.setOnErrorListener(errorListener);
           Log.d(TAG,"after setting errorListener");
           mPlayer.prepareAsync();
           Log.d(TAG,"after prepareAsync");

参考代码是这样的：在我的主要活动的 onResume() 中（返回到哪个，我想开始播放）我正在调用 MusicUtils.createPlayer();和 MusicUtils.playTrack(mCurrentTrack);

public static void playTrack(String track) {

    mTrackToBePlayed = track;   

    try {
           mPlayer.reset();
           Log.d(TAG,"after reset");
           mPlayer.setDataSource(mTrackToBePlayed);
           Log.d(TAG,"after setDataSource");
          // mPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
           mPlayer.setOnPreparedListener(preparedListener);
           Log.d(TAG,"after setOnPreparedListener");
           mPlayer.setOnErrorListener(errorListener);
           Log.d(TAG,"after setting errorListener");
           mPlayer.prepareAsync();
           Log.d(TAG,"after prepareAsync");

    } catch (IOException e) {

    } catch(IllegalArgumentException e) {

    }

    preparedListener = new MediaPlayer.OnPreparedListener() {

        @Override
        public void onPrepared(MediaPlayer mp) {
            // TODO Auto-generated method stub
            mp.start();
            Log.d(TAG,"after start");
        }
    };

     errorListener = new MediaPlayer.OnErrorListener() {
         public boolean onError(MediaPlayer mp, int what, int extra) {
             switch (what) {
             case MediaPlayer.MEDIA_ERROR_SERVER_DIED:
                 Log.d(TAG,"in onError");
                // mIsInitialized = false;
                 mp.release();
                 // Creating a new MediaPlayer and settings its wakemode does not
                 // require the media service, so it's OK to do this now, while the
                 // service is still being restarted
                try{
                 mp = new MediaPlayer(); 
                 mp.reset();
                 mp.setDataSource(mTrackToBePlayed);
                // mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
                 mp.prepareAsync();
                 mPlayer = mp;
                // mPlayer.start();
                } catch (Exception e) {

                }
                 //MediaPlayer.create(mContext, mTrackToBePlayed);
                // mPlayer.setWakeMode(MediaPlaybackService.this, PowerManager.PARTIAL_WAKE_LOCK);                 
                 return true;
             default:
                 Log.d("MusicPlayer", "Error: " + what + "," + extra);
                 break;
             }
             return false;
        }
     };


    //mPlayer.start();

}

public static boolean isPlaying() {
    return mPlayer.isPlaying();
}

public static void pauseTrack() {
    mPlayer.pause();
}

public static void startTrack() {
    mPlayer.start();
}

public static void stopTrack() {
    mPlayer.stop();
}

public static void releasePlayer() {
    mPlayer.release();
}

此函数存在于 MusicUtils 中，用于获取光标返回的第一首曲目

public static void retrieveDefaultPath() {

    String[] STAR = { "*" };           
    Uri allsongsuri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;    
    String selection = MediaStore.Audio.Media.IS_MUSIC + " != 0";     
    mCursor = mContentResolver.query(allsongsuri, STAR, selection, null, null);     
    if (mCursor != null) {        
        if (mCursor.moveToFirst()) {          
            //do {               
                //mSongName = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DISPLAY_NAME));   
                //mSongList.add(mSongName);//populate the list of display names
                int song_id = mCursor.getInt(mCursor.getColumnIndex(MediaStore.Audio.Media._ID));   
                //mMusicIDs.put(song_id, counter++);//fill the HashMap with IDs corresponding to the positions
                String fullpath = mCursor.getString(mCursor.getColumnIndex(MediaStore.Audio.Media.DATA));            
                String album_name = mCursor.getString(mCursor.getColumnIndex(MediaStore.Audio.Media.ALBUM));          
                int album_id = mCursor.getInt(mCursor.getColumnIndex(MediaStore.Audio.Media.ALBUM_ID));               
                String artist_name = mCursor.getString(mCursor.getColumnIndex(MediaStore.Audio.Media.ARTIST));         
                int artist_id = mCursor.getInt(mCursor.getColumnIndex(MediaStore.Audio.Media.ARTIST_ID));        
                //} while (cursor.moveToNext());       


                 mDefaultPath = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI + "/" + song_id;
                 Slideshow.mCurrentTrack = mDefaultPath;

    }      
        if  (mCursor != null) { 
             mCursor.close();   
        }
    } 
}

The following function is used to obtain all the tracks on the device to display using the ListActivity.

public void getAllSongsFromSDCARD()  {     
    String[] STAR = { "*" };           
    Uri allsongsuri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;    
    String selection = MediaStore.Audio.Media.IS_MUSIC + " != 0";     
    cursor = managedQuery(allsongsuri, STAR, selection, null, null);     
    if (cursor != null) {        
        if (cursor.moveToFirst()) {          
            do {               
                mSongName = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DISPLAY_NAME));   
                mSongList.add(mSongName);//populate the list of display names
                int song_id = cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Media._ID));   
                Log.d("Music List","ID: "+song_id+" counter:"+counter);

                mMusicIDs.put(counter++, song_id);//fill the HashMap with IDs corresponding to the positions
                String fullpath = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DATA));            
                String album_name = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM));          
                int album_id = cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM_ID));               
                String artist_name = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ARTIST));         
                int artist_id = cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Media.ARTIST_ID));        
                } while (cursor.moveToNext());       
    }      
       cursor.close();    
    } 
}

我使用用户选择的ID并通过以下方式获取文件路径：

 music_id = (Integer)mMusicIDs.get(position);
 mSelectedPath = mSelectedPath + "/" + music_id;

Logcat：

08-31 18:07:36.348: D/dalvikvm(23090): GC_EXTERNAL_ALLOC 释放 2K，46% 释放 3088K/5703K，外部 1461K/1538K，暂停 32ms

08-31 18:07:38.860: D/tag(23090): oncreate 内部

08-31 18:07:38.860：D/ImageSwitcher(23090)：缓存大小：1

08-31 18:07:39.030：D/ImageSwitcher(23090)：图像总数：838

08-31 18:07:39.150：I/AudioSystem(23090)：获取音频抛掷器

08-31 18:07:39.150：I/AudioSystem(23090)：返回新的音频会话 ID

08-31 18:07:39.150: D/IAudioFlinger(23090): newAudioSessionId In

08-31 18:07:39.150: D/IAudioFlinger(23090): newAudioSessionId Out, id = 175

08-31 18:07:39.150: D/MediaPlayer(23090): reset() in

08-31 18:07:39.150: D/MediaPlayer(23090): reset() out

08-31 18:07:39.150：D/MusicUtils(23090)：重置后

08-31 18:07:39.160: D/MusicUtils(23090): 在 setDataSource 之后

08-31 18:07:39.160: D/MusicUtils(23090): 在 setOnPreparedListener 之后

08-31 18:07:39.160: D/MusicUtils(23090): 设置 errorListener 后

08-31 18:07:39.170：D/MusicUtils(23090)：prepareAsync 之后

08-31 18:07:39.250: D/MediaPlayer(23090): start() in

08-31 18:07:39.260: D/MediaPlayer(23090): start() out

08-31 18:07:39.270: D/MediaPlayer(23090): start() in

08-31 18:07:39.270: D/MediaPlayer(23090): start() out

08-31 18:07:39.270: D/MusicUtils(23090): 开始后

08-31 18:07:49.340: D/MediaPlayer(23090): pause() in

08-31 18:07:49.340: D/MediaPlayer(23090): pause() out 08-31 18:07:49.560: D/dalvikvm(23090): GC_CONCURRENT freed 239K, 45% free 3260K/5831K, external 494K/1006K, paused 10ms+7ms

08-31 18:07:50.842: D/Music List(23090): 在 getAllSongsFromSDCARD 之前的 onCreate 中

08-31 18:07:50.922: D/TAG(23090): 设置适配器

08-31 18:07:50.922: D/TAG(23090): 设置适配器完成

08-31 18:07:51.953: D/dalvikvm(23090): GC_EXTERNAL_ALLOC 释放 146K，45% 释放 3264K/5831K，外部 794K/855K，暂停 29ms

08-31 18:07:53.905: D/MusicList(23090): 在 setItemChecked 之后

08-31 18:07:54.585: D/Settings(23090): onActivityResult 内部

08-31 18:07:55.476：W/KeyCharacterMap(23090)：无法打开 keycharmap 文件

08-31 18:07:55.476: W/KeyCharacterMap(23090): 加载 keycharmap 时出错

文件'/system/usr/keychars/cy8c-touchscreen.kcm.bin'。 hw.keyboards.65538.devname='cy8c-touchscreen' 08-31 18:07:55.476: I/KeyCharacterMap(23090): 使用默认值键盘映射：/system/usr/keychars/qwerty.kcm.bin

08-31 18:07:55.486: D/MediaPlayer(23090): reset() in

08-31 18:07:55.486: D/MediaPlayer(23090): reset() out

08-31 18:07:55.486: D/MusicUtils(23090): 重置后

08-31 18:07:55.486: D/MusicUtils(23090): 在 setDataSource 之后

08-31 18:07:55.486: D/MusicUtils(23090): 在 setOnPreparedListener 之后

08-31 18:07:55.486: D/MusicUtils(23090): 设置 errorListener 后

08-31 18:07:55.486：D/MusicUtils(23090)：prepareAsync 之后

08-31 18:07:55.496: E/MediaPlayer(23090): 错误 (1, -2147483648)

08-31 18:07:55.506: E/MediaPlayer(23090): 错误 (1,-2147483648)

08-31 18:07:55.506: D/MusicPlayer(23090): 错误: 1,-2147483648

【问题讨论】：

设置这行代码'mp.setAudioStreamType(AudioManager.STREAM_MUSIC);'在设置数据源之前。我想这会对你有所帮助。
@Satheesh：我试过了，没用。
好的，当您从路径设置数据源值时，请尝试使用这两行代码“FileInputStream fis = new FileInputStream(mTrackToBePlayed); mPlayer.setDataSource(fis.getFD());”来设置数据源值。
这是为了检查文件是否创建成功？我试过这个。但是，默认曲目也不播放！（用于在幻灯片启动时播放的默认曲目）。现在，我得到了日志 - 在状态 1 中调用 start 和 error(-38,0)
您的文件在哪里？在 sdcard 上还是在应用程序路径上？

标签： android android-mediaplayer mediaplayback

【解决方案1】：

**Check with the following class it will list out all th songs in the device also it play the song when click on that name.**



public class NewMp3PlayerActivity extends Activity {
       ListView musiclist;

      int music_column_index,music_column_index1;
      int count;
      MediaPlayer mMediaPlayer;
      ImageView play, pause, forward, backward;
      int pposition;
      ArrayList<String> songs = new ArrayList<String>();      String songName;    Cursor musiccursor;
      /** Called when the activity is first created. */
      @Override
      public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.songpreview);

            play = (ImageView)findViewById(R.id.img_play);
            pause = (ImageView)findViewById(R.id.img_pause);
            forward = (ImageView)findViewById(R.id.img_forward);
            backward = (ImageView)findViewById(R.id.img_backward);

            play.setOnClickListener(OnClick);
            pause.setOnClickListener(OnClick);
            forward.setOnClickListener(OnClick);
            backward.setOnClickListener(OnClick);
            init_phone_music_grid();


      }

      View.OnClickListener OnClick = new View.OnClickListener() {
                @Override       public void onClick(View v) {           music_column_index = musiccursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA);        

            Log.e("", "musiccursor.getCount()-->"musiccursor.getCount());           switch(v.getId()){          case R.id.img_play:
                Log.v("", "list of songs-->"+songs);
                  if (mMediaPlayer.isPlaying()) {
                      mMediaPlayer.reset();
                }
                  mMediaPlayer.start();
                break;          case R.id.img_pause:
                  if (mMediaPlayer.isPlaying()) {
                      mMediaPlayer.pause();
                }
                break;          case R.id.img_forward: //                musiccursor.moveToPosition(pposition+1);

                try {
                     String filename="";
                        if (pposition < songs.size()){
                            pposition = pposition+1;
                            filename = songs.get(pposition);//musiccursor.getString(music_column_index);
                        }else{

                        }

                        Log.e("", "filename-->"+filename);
                    mMediaPlayer.reset();
                    mMediaPlayer.setDataSource(filename);
                    mMediaPlayer.prepare();
                    mMediaPlayer.start();
                } catch (IllegalArgumentException e) {
                    e.printStackTrace();
                } catch (IllegalStateException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } catch(IndexOutOfBoundsException ie){
                    pposition = 0;
                }

                break;          case R.id.img_backward:

                 try {
                     String filename_n="";
                        if (pposition <= songs.size()){
                            pposition = pposition-1;
                            filename_n = songs.get(pposition);//musiccursor.getString(music_column_index);
                        }else{

                        }
                        mMediaPlayer.reset();
                        mMediaPlayer.setDataSource(filename_n);
                        mMediaPlayer.prepare();
                        mMediaPlayer.start();
                    } catch (IllegalArgumentException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } catch (IllegalStateException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    } catch(ArrayIndexOutOfBoundsException ar){
                        pposition = songs.size();
                    }
                break;          default:
                break;          }
                    }   };
      private void init_phone_music_grid() {
            System.gc(); 
            String[] proj = { MediaStore.Audio.Media._ID,MediaStore.Audio.Media.DATA,MediaStore.Audio.Media.DISPLAY_NAME,MediaStore.Video.Media.SIZE };
            musiccursor = managedQuery(MediaStore.Audio.Media.INTERNAL_CONTENT_URI, proj, null, null, null);
            Log.e("", "filename-->"musiccursor.getCount());
            count = musiccursor.getCount();
            musiclist = (ListView) findViewById(R.id.lst_music);
            musiclist.setAdapter(new MusicAdapter(getApplicationContext()));

            musiclist.setOnItemClickListener(musicgridlistener);
            mMediaPlayer = new MediaPlayer();
            mMediaPlayer.setOnCompletionListener(new OnCompletionListener() {

                @Override
                public void onCompletion(MediaPlayer mp) {
                    try {
                         String filename="";
                            if (pposition < songs.size()){
                                pposition = pposition+1;
                                filename = songs.get(pposition);//musiccursor.getString(music_column_index);
                            }else{

                            }

                            Log.e("", "filename-->"+filename);
                        mMediaPlayer.reset();
                        mMediaPlayer.setDataSource(filename);
                        mMediaPlayer.prepare();
                        mMediaPlayer.start();
                    } catch (IllegalArgumentException e) {
                        e.printStackTrace();
                    } catch (IllegalStateException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    } catch(IndexOutOfBoundsException ie){
                        pposition = 0;
                    }
                }           });
      }

      private OnItemClickListener musicgridlistener = new OnItemClickListener() {
            public void onItemClick(AdapterView parent, View v, int position,long id) {
                  System.gc();
                  pposition = position;
                  music_column_index = musiccursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA);
                  musiccursor.moveToPosition(position);
                  String filename = musiccursor.getString(music_column_index);
                  String filen = songs.get(pposition);
                  Log.e("", "index-->"+music_column_index);
                  try {
                        mMediaPlayer.reset();
                        mMediaPlayer.setDataSource(filen);
                        mMediaPlayer.prepare(); //                        mMediaPlayer.start();
                  } catch (Exception e) {

                  }
            }
      };



      public class MusicAdapter extends BaseAdapter {
            private Context mContext;

            public MusicAdapter(Context c) {
                  mContext = c;
            }

            public int getCount() {
                  return count;
            }

            public Object getItem(int position) {
                  return position;
            }

            public long getItemId(int position) {
                  return position;
            }

            public View getView(int position, View convertView, ViewGroup parent) {
                  System.gc();
                  TextView tv = new TextView(mContext.getApplicationContext());
                  String id = null;
                  if (convertView == null) {                     
                        music_column_index = musiccursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME);
                        music_column_index1 = musiccursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA);
                        musiccursor.moveToPosition(position);
                        id = musiccursor.getString(music_column_index);
                        songName = musiccursor.getString(music_column_index);
                        songs.add( musiccursor.getString(music_column_index1) );
                        music_column_index = musiccursor.getColumnIndexOrThrow(MediaStore.Audio.Media.SIZE);
                        musiccursor.moveToPosition(position);
                        id += " Size(KB):" + musiccursor.getString(music_column_index);
                        tv.setText(id);
                  } else
                        tv = (TextView) convertView;
                  return tv;
            }
      } }

【讨论】：

我试过了，不行。就像我之前说的，如果我按照上述方式播放默认曲目，则不会播放。我最初的实现会播放默认曲目。我看过很多代码示例。我找不到任何我想念的东西。那是什么错误（1，-2148..）？
好的。你的文件在哪里？在 sdcard 上还是在应用程序路径上？以及您以哪种方式获得 fil 路径，例如静态为“sdcard/media/new.mp3”，或者使用 Environment.getExtrnalStorage
请检查上面的编辑，看看我是如何获得文件路径的。文件在sd卡上。我还尝试在 mPlayer.pause() 之后播放相同的文件（第一首曲目）。因此，我调用了 playTrack(currentTrack)。但是，这给了我同样的错误并且没有播放。这意味着路径不是问题吗？因为即使是相同的文件在暂停后也无法播放。但是，如果我在 pause() 之后执行 mPlayer.start()，它可以工作，但我无法更改曲目。
另外，在你的 onPreparedListener 中，你在类变量上调用 start。我们不应该在回调收到的实例上这样做吗？是一样的吗？
“另外，在你的 onPreparedListener 中，你在类变量上调用 start。我们不应该在回调收到的实例上做吗？是一样的吗？”两者都是一样的。

【解决方案2】：

顺序是正确的。这条路走错了。正在使用硬编码字符串而不是 Uri。谢谢。

【讨论】：