Question

我目前正在制作一个简单的音乐播放器，我已经设法通过下面的示例脚本从媒体获取音乐列表。然而，问题在于我不知道如何从ContentResolver播放音乐。我读过http://developer.android.com/reference/android/provider/MediaStore.Audio.html但很难理解。有好的样本或教程吗？我想要实现的只是在Android中播放来自ContentResolver的音乐。

   public  Track(Cursor cursor)
    {
        id              = cursor.getLong( cursor.getColumnIndex( MediaStore.Audio.Media._ID ));
        path            = cursor.getString( cursor.getColumnIndex(MediaStore.Audio.Media.DATA));
        title           = cursor.getString( cursor.getColumnIndex( MediaStore.Audio.Media.TITLE ));
        album           = cursor.getString( cursor.getColumnIndex( MediaStore.Audio.Media.ALBUM ));
        artist          = cursor.getString( cursor.getColumnIndex( MediaStore.Audio.Media.ARTIST ));
        albumId         = cursor.getLong( cursor.getColumnIndex( MediaStore.Audio.Media.ALBUM_ID ));
        artistId        = cursor.getLong( cursor.getColumnIndex( MediaStore.Audio.Media.ARTIST_ID ));
        duration        = cursor.getLong( cursor.getColumnIndex( MediaStore.Audio.Media.DURATION ));
        trackNo         = cursor.getInt( cursor.getColumnIndex( MediaStore.Audio.Media.TRACK ));
        uri             = ContentUris.withAppendedId(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, id);
    }

    public static List getItems(Context activity) {

        List tracks = new ArrayList();
        ContentResolver resolver = activity.getContentResolver();
        Cursor cursor = resolver.query(
                MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
                Track.COLUMNS,
                null,
                null,
                null
        );
        while( cursor.moveToNext() ){
            if( cursor.getLong(cursor.getColumnIndex( MediaStore.Audio.Media.DURATION)) < 3000 ){continue;}
            tracks.add(new Track(cursor));
        }
        cursor.close();
        return tracks;
    }

Answer 1

以下是Google提供的文档，我引用：

在媒体播放器应用程序中可能有用的另一个功能是能够检索用户在设备上拥有的音乐。您可以通过查询ContentResolver获取外部媒体来实现这一目的：

ContentResolver contentResolver = getContentResolver();
Uri uri = android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
Cursor cursor = contentResolver.query(uri, null, null, null, null);
if (cursor == null) {
    // query failed, handle error.
} else if (!cursor.moveToFirst()) {
    // no media on the device
} else {
    int titleColumn = cursor.getColumnIndex(android.provider.MediaStore.Audio.Media.TITLE);
    int idColumn = cursor.getColumnIndex(android.provider.MediaStore.Audio.Media._ID);
    do {
       long thisId = cursor.getLong(idColumn);
       String thisTitle = cursor.getString(titleColumn);
       // ...process entry...
    } while (cursor.moveToNext());
}

要将其与MediaPlayer一起使用，您可以执行以下操作：

long id = /* retrieve it from somewhere */;
Uri contentUri = ContentUris.withAppendedId(
        android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, id);

mMediaPlayer = new MediaPlayer();
mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
mMediaPlayer.setDataSource(getApplicationContext(), contentUri);

// ...prepare and start...

来源： Media Playback: Retrieving Media from a Content Resolver

无法在Android中使用MediaPlayer播放MediaStore.Audio歌曲

1 个答案: