android 音乐播放器----获取专辑封面图片

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http://blog.csdn.net/dany1202/archive/2011/06/08/6532024.aspx

.mp3歌曲中，附带有专辑封面的图片，如何解析获取并显示这张图片呢？如图：

该图片为使用如下代码解析得到：

参考源码中，音乐目录：

packages/apps/Music/src/com/android/music/MusicUtils.java中函数：getArtwork(context, song_id, album_id, true)

public static Bitmap getArtwork(Context context, long song_id, long album_id,
            boolean allowdefault) {
        if (album_id < 0) {
            // This is something that is not in the database, so get the album art directly
            // from the file.
            if (song_id >= 0) {
                Bitmap bm = getArtworkFromFile(context, song_id, -1);
                if (bm != null) {
                    return bm;
                }
            }
            if (allowdefault) {
                return getDefaultArtwork(context);
            }
            return null;
        }
        ContentResolver res = context.getContentResolver();
        Uri uri = ContentUris.withAppendedId(sArtworkUri, album_id);
        if (uri != null) {
            InputStream in = null;
            try {
                in = res.openInputStream(uri);
                return BitmapFactory.decodeStream(in, null, sBitmapOptions);
            } catch (FileNotFoundException ex) {
                // The album art thumbnail does not actually exist. Maybe the user deleted it, or
                // maybe it never existed to begin with.
                Bitmap bm = getArtworkFromFile(context, song_id, album_id);
                if (bm != null) {
                    if (bm.getConfig() == null) {
                        bm = bm.copy(Bitmap.Config.RGB_565, false);
                        if (bm == null && allowdefault) {
                            return getDefaultArtwork(context);
                        }
                    }
                } else if (allowdefault) {
                    bm = getDefaultArtwork(context);
                }
                return bm;
            } finally {
                try {
                    if (in != null) {
                        in.close();
                    }
                } catch (IOException ex) {
                }
            }
        }
        
        return null;
    }
    
    private static Bitmap getArtworkFromFile(Context context, long songid, long albumid) {
        Bitmap bm = null;
        byte [] art = null;
        String path = null;
        if (albumid < 0 && songid < 0) {
            throw new IllegalArgumentException("Must specify an album or a song id");
        }
        try {
            if (albumid < 0) {
                Uri uri = Uri.parse("content://media/external/audio/media/" + songid + "/albumart");
                ParcelFileDescriptor pfd = context.getContentResolver().openFileDescriptor(uri, "r");
                if (pfd != null) {
                    FileDescriptor fd = pfd.getFileDescriptor();
                    bm = BitmapFactory.decodeFileDescriptor(fd);
                }
            } else {
                Uri uri = ContentUris.withAppendedId(sArtworkUri, albumid);
                ParcelFileDescriptor pfd = context.getContentResolver().openFileDescriptor(uri, "r");
                if (pfd != null) {
                    FileDescriptor fd = pfd.getFileDescriptor();
                    bm = BitmapFactory.decodeFileDescriptor(fd);
                }
            }
        } catch (FileNotFoundException ex) {
 
        }
        if (bm != null) {
            mCachedBit = bm;
        }
        return bm;
    }
    
    private static Bitmap getDefaultArtwork(Context context) {
        BitmapFactory.Options opts = new BitmapFactory.Options();
        opts.inPreferredConfig = Bitmap.Config.RGB_565;        
        return BitmapFactory.decodeStream(
                context.getResources().openRawResource(R.drawable.play_img_default), null, opts);               
    }
private static final Uri sArtworkUri = Uri.parse("content://media/external/audio/albumart");
    private static final BitmapFactory.Options sBitmapOptions = new BitmapFactory.Options();
    private static Bitmap mCachedBit = null;

获取cursor:

myCur = getContentResolver().query(
				MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
				new String[] { MediaStore.Audio.Media.TITLE,
						MediaStore.Audio.Media.DURATION,
						MediaStore.Audio.Media.ARTIST,
						MediaStore.Audio.Media._ID,
						MediaStore.Audio.Media.ALBUM,
						MediaStore.Audio.Media.DISPLAY_NAME,
						MediaStore.Audio.Media.DATA,
						MediaStore.Audio.Media.ALBUM_ID}, null,null, null);
		myCur.moveToPosition(position);

设置专辑封面图片：

long songid = myCur.getLong(3);
		long albumid = myCur.getLong(7);
		Bitmap bm = MusicUtils.getArtwork(this, songid, albumid,true);
		if(bm != null){
			Log.d(TAG,"bm is not null==========================");
			playImg.setImageBitmap(bm);
		}else{
			Log.d(TAG,"bm is null============================");
		}