Android仿虾米音乐播放器之本地音乐获取

Android系统为了一些常用的信息(如音乐、视频、图像、联系人等)内置了一系列的ContentProvider，所以我们可以通过这个来获取Anroid中本地音乐，首先得加入权限

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

如果想要修改甚至删除数据，还要加上写的权限

为了实例化mp3音乐,我们首先定义一个mp3info的bean，里面给出所需要的属性，比如id，title，album等等，另外为了使其能在activity与service中进行通信传值，需要序列化，android中序列化一般使用Parcelable，用法可以参考点击打开链接

mp3info.java

public class Mp3Info implements Parcelable{private long id;private String title;private String artist;private String album;private long albumId;private long duration;private long size;private String url;public Mp3Info(){}public Mp3Info(Parcel parcel){id = parcel.readLong();title = parcel.readString();artist = parcel.readString();album = parcel.readString();albumId = parcel.readLong();duration = parcel.readLong();size = parcel.readLong();url = parcel.readString();}public long getId() {return id;}public void setId(long id) {this.id = id;}public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public String getArtist() {return artist;}public void setArtist(String artist) {this.artist = artist;}public String getAlbum() {return album;}public void setAlbum(String album) {this.album = album;}public long getAlbumId() {return albumId;}public void setAlbumId(long albumId) {this.albumId = albumId;}public long getDuration() {return duration;}public void setDuration(long duration) {this.duration = duration;}public long getSize() {return size;}public void setSize(long size) {this.size = size;}public String getUrl() {return url;}public void setUrl(String url) {this.url = url;}@Overridepublic int describeContents() {return 0;}@Overridepublic void writeToParcel(Parcel dest, int flags) {dest.writeLong(id);dest.writeString(title);dest.writeString(artist);dest.writeString(album);dest.writeLong(albumId);dest.writeLong(duration);dest.writeLong(size);dest.writeString(url);}public static final Parcelable.Creator<Mp3Info> CREATOR = new Creator<Mp3Info>() {@Overridepublic Mp3Info[] newArray(int size) {return new Mp3Info[size];}@Overridepublic Mp3Info createFromParcel(Parcel source) {return new Mp3Info(source);}};}

获取本地音乐及其专辑图片的代码，部分参考他人代码， MediaUtil.java

// 获取专辑封面的Uriprivate static final Uri albumArtUri = Uri.parse("content://media/external/audio/albumart");/*** 用于从数据库中查询歌曲的信息，保存在List当中* * @return*/public static List<Mp3Info> getMp3Infos(Context context) {Cursor cursor = context.getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null, null,MediaStore.Audio.Media .DEFAULT_SORT_ORDER);List<Mp3Info> mp3Infos = new ArrayList<Mp3Info>();for (int i = 0; i < cursor.getCount(); i++) {cursor.moveToNext();Mp3Info mp3Info = new Mp3Info();long id = cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media._ID)); // 音乐idString title = cursor.getString((cursor.getColumnIndex(MediaStore.Audio.Media.TITLE))); // 音乐标题String artist = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ARTIST)); // 艺术家String album = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM)); // 专辑long albumId = cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM_ID));long duration = cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media.DURATION)); // 时长long size = cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media.SIZE)); // 文件大小String url = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DATA)); // 文件路径int isMusic = cursor.getInt(cursor.getColumnIndex(MediaStore.Audio.Media.IS_MUSIC)); // 是否为音乐if (isMusic != 0) { // 只把音乐添加到集合当中mp3Info.setId(id);mp3Info.setTitle(title);mp3Info.setArtist(artist);mp3Info.setAlbum(album);mp3Info.setAlbumId(albumId);mp3Info.setDuration(duration);mp3Info.setSize(size);mp3Info.setUrl(url);mp3Infos.add(mp3Info);}}cursor.close();return mp3Infos;}/*** 格式化时间，将毫秒转换为分:秒格式* * @param time* @return*/public static String formatTime(long time) {String min = time / (1000 * 60) + "";String sec = time % (1000 * 60) + "";if (min.length() < 2) {min = "0" + time / (1000 * 60) + "";} else {min = time / (1000 * 60) + "";}if (sec.length() == 4) {sec = "0" + (time % (1000 * 60)) + "";} else if (sec.length() == 3) {sec = "00" + (time % (1000 * 60)) + "";} else if (sec.length() == 2) {sec = "000" + (time % (1000 * 60)) + "";} else if (sec.length() == 1) {sec = "0000" + (time % (1000 * 60)) + "";}return min + ":" + sec.trim().substring(0, 2);}/*** 获取默认专辑图片* * @param context* @return*/public static Bitmap getDefaultArtwork(Context context, boolean small) {BitmapFactory.Options opts = new BitmapFactory.Options();opts.inPreferredConfig = Bitmap.Config.RGB_565;if (small) { // 返回小图片,文件路径为默认的图片return BitmapFactory.decodeStream(context.getResources().openRawResource(R.drawable.default_cover_64), null, opts);}return BitmapFactory.decodeStream(context.getResources().openRawResource(R.drawable.default_cover_640), null, opts);}/*** 从文件当中获取专辑封面位图* * @param context* @param songid* @param albumid* @return*/private static Bitmap getArtworkFromFile(Context context, long songid,long albumid) {Bitmap bm = null;if (albumid < 0 && songid < 0) {throw new IllegalArgumentException("Must specify an album or a song id");}try {BitmapFactory.Options options = new BitmapFactory.Options();FileDescriptor fd = null;if (albumid < 0) {Uri uri = Uri.parse("content://media/external/audio/media/"+ songid + "/albumart");ParcelFileDescriptor pfd = context.getContentResolver().openFileDescriptor(uri, "r");if (pfd != null) {fd = pfd.getFileDescriptor();}} else {Uri uri = ContentUris.withAppendedId(albumArtUri, albumid);ParcelFileDescriptor pfd = context.getContentResolver().openFileDescriptor(uri, "r");if (pfd != null) {fd = pfd.getFileDescriptor();}}options.inSampleSize = 1;// 只进行大小判断options.inJustDecodeBounds = true;// 调用此方法得到options得到图片大小BitmapFactory.decodeFileDescriptor(fd, null, options);// 我们的目标是在800pixel的画面上显示// 所以需要调用computeSampleSize得到图片缩放的比例options.inSampleSize = 100;// 我们得到了缩放的比例，现在开始正式读入Bitmap数据options.inJustDecodeBounds = false;options.inDither = false;options.inPreferredConfig = Bitmap.Config.ARGB_8888;// 根据options参数，减少所需要的内存bm = BitmapFactory.decodeFileDescriptor(fd, null, options);} catch (FileNotFoundException e) {e.printStackTrace();}return bm;}/*** 获取专辑封面位图对象* * @param context* @param song_id* @param album_id* @param allowdefalut* @return*/public static Bitmap getArtwork(Context context, long song_id,long album_id, boolean allowdefalut, boolean small) {if (album_id < 0) {if (song_id < 0) {Bitmap bm = getArtworkFromFile(context, song_id, -1);if (bm != null) {return bm;}}if (allowdefalut) {return getDefaultArtwork(context, small);}return null;}ContentResolver res = context.getContentResolver();Uri uri = ContentUris.withAppendedId(albumArtUri, album_id);if (uri != null) {InputStream in = null;try {in = res.openInputStream(uri);BitmapFactory.Options options = new BitmapFactory.Options();// 先制定原始大小options.inSampleSize = 1;// 只进行大小判断options.inJustDecodeBounds = true;// 调用此方法得到options得到图片的大小BitmapFactory.decodeStream(in, null, options);/** 我们的目标是在你N pixel的画面上显示。 所以需要调用computeSampleSize得到图片缩放的比例 **//** 这里的target为800是根据默认专辑图片大小决定的，800只是测试数字但是试验后发现完美的结合 **/if (small) {options.inSampleSize = computeSampleSize(options, 40);} else {options.inSampleSize = computeSampleSize(options, 600);}// 我们得到了缩放比例，现在开始正式读入Bitmap数据options.inJustDecodeBounds = false;options.inDither = false;options.inPreferredConfig = Bitmap.Config.ARGB_8888;in = res.openInputStream(uri);return BitmapFactory.decodeStream(in, null, options);} catch (FileNotFoundException e) {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 && allowdefalut) {return getDefaultArtwork(context, small);}}} else if (allowdefalut) {bm = getDefaultArtwork(context, small);}return bm;} finally {try {if (in != null) {in.close();}} catch (IOException e) {e.printStackTrace();}}}return null;}/*** 对图片进行合适的缩放* * @param options* @param target* @return*/public static int computeSampleSize(Options options, int target) {int w = options.outWidth;int h = options.outHeight;int candidateW = w / target;int candidateH = h / target;int candidate = Math.max(candidateW, candidateH);if (candidate == 0) {return 1;}if (candidate > 1) {if ((w > target) && (w / candidate) < target) {candidate -= 1;}}if (candidate > 1) {if ((h > target) && (h / candidate) < target) {candidate -= 1;}}return candidate;}