android音乐播放器开发 SweetMusicPlayer 载入歌曲列表
上一篇写了播放器的总体实现思路,http://blog.csdn.net/huweigoodboy/article/details/39855653,如今来总结下载入歌曲列表。
代码地址:https://github.com/huweigoodboy/SweetMusicPlayer
比較好的实现思路就是。自己维护一个SQLite数据库,然后音乐信息都从sd卡上扫描,优点有非常多,可是这样做的话代码量会比較大,写了一段扫描sd卡的代码。然后发现扫描音乐的速度简直慢的惊人,可能自己的文件夹太多,太深。眼下还没想到一个比較好的算法去高速扫描sd卡。
楼主比較偷懒,android自己本身有一个关于媒体信息的数据库。直接用这个就够了,你可能又要吐槽了,假设我要制作一个能在线播放音乐的播放器,下载歌曲后。这个自带的数据库不刷新歌曲怎么办。哈哈。我这是个本地播放器。我就不考虑这些事了。
不,作为一个程序猿。这样的态度可不好。
我眼下能想到的是。每次下完一首歌让android系统自己去扫描一下。
ok,还是进入正题吧。
一,从数据库载入歌曲信息
已经存在这个数据库,我们就直接从里面获取呗,android系统通过ContextProvider把这个暴露出来。我们仅仅须要获得一个ContextResolver对象去获得歌曲信息。
基本的方法
Cursor android.content.ContentResolver.query(Uri
uri, String[] projection,String
selection,String[] selectionArgs,String
sortOrder)
然后把首字母同样的列表项排在一起。在显示的仅显示第一个。
![](//img-blog.csdn.net/20141007220023312?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvaHV3ZWlnb29kYm95/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast)
上面參数的主要意思是:
uri通用资源訪问符。在这里MediaStore.Audio.Media.EXTERNAL_CONTENT_URI
projection返回信息的行,用一个数组去设置要返回哪些行的信息
selection筛选条件
selectionArgs筛选条件的參数
sortOrder排序的顺序 这个用默认的就好了MediaStore.Audio.Media.DEFAULT_SORT_ORDER
关键代码
public void loadSongFromSQL(){
Cursor cursor= getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, MusicManager.media_info, null, null, MediaStore.Audio.Media.DEFAULT_SORT_ORDER);
cursor.moveToFirst();
//游标遍历数据库
for(int i=0;i<cursor.getCount();i++){
Song song=new Song();
song.setTitle(cursor.getString(0));
song.setArtist(cursor.getString(2));
song.setDuration(Integer.parseInt(cursor.getString(1)));
song.setId(cursor.getInt(3));
song.setPath(cursor.getString(5));
//增加song到MusicManager
MusicManager.getInstance().addSong(song);
cursor.moveToNext();
}
//关闭游标
cursor.close();
}
存放歌曲信息的类
Song.java
package com.huwei.sweetmusicplayer.models;
import java.io.Serializable;
import com.huwei.sweetmusicplayer.util.CharacterParser;
import com.huwei.sweetmusicplayer.util.TimeUtil;
public class Song implements Serializable{
private String title; //歌曲名
private int duration; //时长
private String artist; //艺术家
private int id; //id
private String display_name;
private String data;
private String date_added;
private String path; //歌曲路径
private String sortLetters; //检索的首字母
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getDisplay_name() {
return display_name;
}
public void setDisplay_name(String display_name) {
this.display_name = display_name;
}
public String getData() {
return data;
}
public void setData(String data) {
this.data = data;
}
public String getDate_added() {
return date_added;
}
public void setDate_added(String date_added) {
this.date_added = date_added;
}
public Song(){
}
public Song(String title){
super();
this.title=title;
if(title.equals("安居客"))
{
System.out.println();
}
String firstLetter=CharacterParser.getFirstLetter(title);
//正则匹配 ,匹配大写和小写字母
if(firstLetter.matches("^[a-zA-Z]$")){
this.sortLetters=firstLetter.toUpperCase();
}else{
this.sortLetters="#";
}
}
public Song(String title, String sortLetters) {
super();
this.title = title;
this.sortLetters = sortLetters;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getSortLetters() {
return CharacterParser.getFirstUpperLetter(title);
}
public void setSortLetters(String sortLetters) {
this.sortLetters = sortLetters;
}
public String getDurationTime(){
return TimeUtil.toTime(duration);
}
public int getDuration() {
return duration;
}
public void setDuration(int duration) {
this.duration = duration;
}
public String getArtist() {
return artist;
}
public void setArtist(String artist) {
this.artist = artist;
}
public String getPath() {
return path;
}
public void setPath(String path) {
this.path = path;
}
}
在Splash界面从数据库读入歌曲信息,然后在创建SongsFragment时载入歌曲信息。
public void loadSongFromSQL(){ Cursor cursor= getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, MusicManager.media_info, null, null, MediaStore.Audio.Media.DEFAULT_SORT_ORDER); cursor.moveToFirst(); //游标遍历数据库 for(int i=0;i<cursor.getCount();i++){ Song song=new Song(); song.setTitle(cursor.getString(0)); song.setArtist(cursor.getString(2)); song.setDuration(Integer.parseInt(cursor.getString(1))); song.setId(cursor.getInt(3)); song.setPath(cursor.getString(5)); //增加song到MusicManager MusicManager.getInstance().addSong(song); cursor.moveToNext(); } //关闭游标 cursor.close(); }
存放歌曲信息的类
package com.huwei.sweetmusicplayer.models; import java.io.Serializable; import com.huwei.sweetmusicplayer.util.CharacterParser; import com.huwei.sweetmusicplayer.util.TimeUtil; public class Song implements Serializable{ private String title; //歌曲名 private int duration; //时长 private String artist; //艺术家 private int id; //id private String display_name; private String data; private String date_added; private String path; //歌曲路径 private String sortLetters; //检索的首字母 public int getId() { return id; } public void setId(int id) { this.id = id; } public String getDisplay_name() { return display_name; } public void setDisplay_name(String display_name) { this.display_name = display_name; } public String getData() { return data; } public void setData(String data) { this.data = data; } public String getDate_added() { return date_added; } public void setDate_added(String date_added) { this.date_added = date_added; } public Song(){ } public Song(String title){ super(); this.title=title; if(title.equals("安居客")) { System.out.println(); } String firstLetter=CharacterParser.getFirstLetter(title); //正则匹配 ,匹配大写和小写字母 if(firstLetter.matches("^[a-zA-Z]$")){ this.sortLetters=firstLetter.toUpperCase(); }else{ this.sortLetters="#"; } } public Song(String title, String sortLetters) { super(); this.title = title; this.sortLetters = sortLetters; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getSortLetters() { return CharacterParser.getFirstUpperLetter(title); } public void setSortLetters(String sortLetters) { this.sortLetters = sortLetters; } public String getDurationTime(){ return TimeUtil.toTime(duration); } public int getDuration() { return duration; } public void setDuration(int duration) { this.duration = duration; } public String getArtist() { return artist; } public void setArtist(String artist) { this.artist = artist; } public String getPath() { return path; } public void setPath(String path) { this.path = path; } }
在Splash界面从数据库读入歌曲信息,然后在创建SongsFragment时载入歌曲信息。
二,A-Z检索功能:
至于SongsFragment的a-z检索功能,先来讲讲思路,每次得到歌曲名,去获取它的首字母,首字母的获取能够依据ansi编码。
提取第一个字母,得到它的gb2312编码的byte数组,英文占一个字节,中文占两个字节。依据byte数组的长度,所以非常easy推断第一个字符是英文还是中文。
1。英文
能够直接获取ansi值
2,中文
相应的拼音会相应一个值,比方
"a", "ai", "an", "ang"分别相应-20319, -20317, -20304, -20295,容我解释一下。a发音的字符是-20319到-20318,而ai的发音是-20317到-20303。
这些奇怪的负数代表什么呢?依据gb2312编码,汉字由区码(高字节)+位码(低字节)表示。
1)区码:high
01-09区为特殊符号。
16-55区为一级汉字。按拼音排序。
56-87区为二级汉字,按部首/笔画排序。
10-15区及88-94区则未有编码。
0xA1-0xF7(把01-87区的区号加上0xA0)
2)位码:low
就是该分区的第几个汉字
0xA1-0xFE(把01-94加上 0xA0)
比方汉字“啊”,按拼音排序的话,属于16区的第一个字,区码是0xB0(16进制的表示),位码是0xA1,所以区码加位码表示0xB0A1
所以表示该汉字为256*high+low
而上面-20319就是 (256*high+low)-256*256,为什么负数表示呢?我猜想是避免不必要的冲突吧。
详细解析代码:
//单个汉字转成ansi public static int getChsAscii(String chs){ int asc=0; try { byte[] bytes=chs.getBytes("gb2312"); if(bytes==null||bytes.length==0){ throw new RuntimeException("illegal resource string"); } if(bytes.length==1){ //英文字符 asc=bytes[0]; } if(bytes.length==2){ //中文字符 int highByte=256+bytes[0]; int lowByte=256+bytes[1]; asc=(256*highByte+lowByte)-256*256; } } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } return asc; }详细解析的CharacterParser.java
package com.huwei.sweetmusicplayer.util; import java.io.UnsupportedEncodingException; /* * java汉字转拼音*/ public class CharacterParser { //private static LinkedHashMap<String, Integer> spellMap;; private static int[] pyvalue = new int[] {-20319, -20317, -20304, -20295, -20292, -20283, -20265, -20257, -20242, -20230, -20051, -20036, -20032, -20026, -20002, -19990, -19986, -19982, -19976, -19805, -19784, -19775, -19774, -19763, -19756, -19751, -19746, -19741, -19739, -19728, -19725, -19715, -19540, -19531, -19525, -19515, -19500, -19484, -19479, -19467, -19289, -19288, -19281, -19275, -19270, -19263, -19261, -19249, -19243, -19242, -19238, -19235, -19227, -19224, -19218, -19212, -19038, -19023, -19018, -19006, -19003, -18996, -18977, -18961, -18952, -18783, -18774, -18773, -18763, -18756, -18741, -18735, -18731, -18722, -18710, -18697, -18696, -18526, -18518, -18501, -18490, -18478, -18463, -18448, -18447, -18446, -18239, -18237, -18231, -18220, -18211, -18201, -18184, -18183, -18181, -18012, -17997, -17988, -17970, -17964, -17961, -17950, -17947, -17931, -17928, -17922, -17759, -17752, -17733, -17730, -17721, -17703, -17701, -17697, -17692, -17683, -17676, -17496, -17487, -17482, -17468, -17454, -17433, -17427, -17417, -17202, -17185, -16983, -16970, -16942, -16915, -16733, -16708, -16706, -16689, -16664, -16657, -16647, -16474, -16470, -16465, -16459, -16452, -16448, -16433, -16429, -16427, -16423, -16419, -16412, -16407, -16403, -16401, -16393, -16220, -16216, -16212, -16205, -16202, -16187, -16180, -16171, -16169, -16158, -16155, -15959, -15958, -15944, -15933, -15920, -15915, -15903, -15889, -15878, -15707, -15701, -15681, -15667, -15661, -15659, -15652, -15640, -15631, -15625, -15454, -15448, -15436, -15435, -15419, -15416, -15408, -15394, -15385, -15377, -15375, -15369, -15363, -15362, -15183, -15180, -15165, -15158, -15153, -15150, -15149, -15144, -15143, -15141, -15140, -15139, -15128, -15121, -15119, -15117, -15110, -15109, -14941, -14937, -14933, -14930, -14929, -14928, -14926, -14922, -14921, -14914, -14908, -14902, -14894, -14889, -14882, -14873, -14871, -14857, -14678, -14674, -14670, -14668, -14663, -14654, -14645, -14630, -14594, -14429, -14407, -14399, -14384, -14379, -14368, -14355, -14353, -14345, -14170, -14159, -14151, -14149, -14145, -14140, -14137, -14135, -14125, -14123, -14122, -14112, -14109, -14099, -14097, -14094, -14092, -14090, -14087, -14083, -13917, -13914, -13910, -13907, -13906, -13905, -13896, -13894, -13878, -13870, -13859, -13847, -13831, -13658, -13611, -13601, -13406, -13404, -13400, -13398, -13395, -13391, -13387, -13383, -13367, -13359, -13356, -13343, -13340, -13329, -13326, -13318, -13147, -13138, -13120, -13107, -13096, -13095, -13091, -13076, -13068, -13063, -13060, -12888, -12875, -12871, -12860, -12858, -12852, -12849, -12838, -12831, -12829, -12812, -12802, -12607, -12597, -12594, -12585, -12556, -12359, -12346, -12320, -12300, -12120, -12099, -12089, -12074, -12067, -12058, -12039, -11867, -11861, -11847, -11831, -11798, -11781, -11604, -11589, -11536, -11358, -11340, -11339, -11324, -11303, -11097, -11077, -11067, -11055, -11052, -11045, -11041, -11038, -11024, -11020, -11019, -11018, -11014, -10838, -10832, -10815, -10800, -10790, -10780, -10764, -10587, -10544, -10533, -10519, -10331, -10329, -10328, -10322, -10315, -10309, -10307, -10296, -10281, -10274, -10270, -10262, -10260, -10256, -10254}; public static String[] pystr = new String[] {"a", "ai", "an", "ang", "ao", "ba", "bai", "ban", "bang", "bao", "bei", "ben", "beng", "bi", "bian", "biao", "bie", "bin", "bing", "bo", "bu", "ca", "cai", "can", "cang", "cao", "ce", "ceng", "cha", "chai", "chan", "chang", "chao", "che", "chen", "cheng", "chi", "chong", "chou", "chu", "chuai", "chuan", "chuang", "chui", "chun", "chuo", "ci", "cong", "cou", "cu", "cuan", "cui", "cun", "cuo", "da", "dai", "dan", "dang", "dao", "de", "deng", "di", "dian", "diao", "die", "ding", "diu", "dong", "dou", "du", "duan", "dui", "dun", "duo", "e", "en", "er", "fa", "fan", "fang", "fei", "fen", "feng", "fo", "fou", "fu", "ga", "gai", "gan", "gang", "gao", "ge", "gei", "gen", "geng", "gong", "gou", "gu", "gua", "guai", "guan", "guang", "gui", "gun", "guo", "ha", "hai", "han", "hang", "hao", "he", "hei", "hen", "heng", "hong", "hou", "hu", "hua", "huai", "huan", "huang", "hui", "hun", "huo", "ji", "jia", "jian", "jiang", "jiao", "jie", "jin", "jing", "jiong", "jiu", "ju", "juan", "jue", "jun", "ka", "kai", "kan", "kang", "kao", "ke", "ken", "keng", "kong", "kou", "ku", "kua", "kuai", "kuan", "kuang", "kui", "kun", "kuo", "la", "lai", "lan", "lang", "lao", "le", "lei", "leng", "li", "lia", "lian", "liang", "liao", "lie", "lin", "ling", "liu", "long", "lou", "lu", "lv", "luan", "lue", "lun", "luo", "ma", "mai", "man", "mang", "mao", "me", "mei", "men", "meng", "mi", "mian", "miao", "mie", "min", "ming", "miu", "mo", "mou", "mu", "na", "nai", "nan", "nang", "nao", "ne", "nei", "nen", "neng", "ni", "nian", "niang", "niao", "nie", "nin", "ning", "niu", "nong", "nu", "nv", "nuan", "nue", "nuo", "o", "ou", "pa", "pai", "pan", "pang", "pao", "pei", "pen", "peng", "pi", "pian", "piao", "pie", "pin", "ping", "po", "pu", "qi", "qia", "qian", "qiang", "qiao", "qie", "qin", "qing", "qiong", "qiu", "qu", "quan", "que", "qun", "ran", "rang", "rao", "re", "ren", "reng", "ri", "rong", "rou", "ru", "ruan", "rui", "run", "ruo", "sa", "sai", "san", "sang", "sao", "se", "sen", "seng", "sha", "shai", "shan", "shang", "shao", "she", "shen", "sheng", "shi", "shou", "shu", "shua", "shuai", "shuan", "shuang", "shui", "shun", "shuo", "si", "song", "sou", "su", "suan", "sui", "sun", "suo", "ta", "tai", "tan", "tang", "tao", "te", "teng", "ti", "tian", "tiao", "tie", "ting", "tong", "tou", "tu", "tuan", "tui", "tun", "tuo", "wa", "wai", "wan", "wang", "wei", "wen", "weng", "wo", "wu", "xi", "xia", "xian", "xiang", "xiao", "xie", "xin", "xing", "xiong", "xiu", "xu", "xuan", "xue", "xun", "ya", "yan", "yang", "yao", "ye", "yi", "yin", "ying", "yo", "yong", "you", "yu", "yuan", "yue", "yun", "za", "zai", "zan", "zang", "zao", "ze", "zei", "zen", "zeng", "zha", "zhai", "zhan", "zhang", "zhao", "zhe", "zhen", "zheng", "zhi", "zhong", "zhou", "zhu", "zhua", "zhuai", "zhuan", "zhuang", "zhui", "zhun", "zhuo", "zi", "zong", "zou", "zu", "zuan", "zui", "zun", "zuo"}; private static CharacterParser instance; private StringBuilder resource; //单例模式 public CharacterParser getInstance(){ if(instance==null) { instance=new CharacterParser(); } return instance; } public StringBuilder getResource() { return resource; } public void setResource(StringBuilder resource) { this.resource = resource; } //单个汉字转成ansi public static int getChsAscii(String chs){ int asc=0; try { byte[] bytes=chs.getBytes("gb2312"); if(bytes==null||bytes.length==0){ throw new RuntimeException("illegal resource string"); } if(bytes.length==1){ //英文字符 asc=bytes[0]; } if(bytes.length==2){ //中文字符 int highByte=256+bytes[0]; int lowByte=256+bytes[1]; asc=(256*highByte+lowByte)-256*256; } } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } return asc; } //首字符是否是字母 //大写return 1 小写return -1 非retrun 0 public static int firstIsLetter(String name){ int asc=getChsAscii(name.substring(0,1)); if( asc>='A'&&asc<='Z'){//单字符 return 1; }else if(asc>='a'&&asc<='z'){ return -1; }else{ return 0; } } //提取首字母,大写和小写均可 public static String getSpellByAscii(int asc){ String res=null; if(asc>0&&asc<160){//单字符 res=String.valueOf((char)asc); } else if (asc< -20319 || asc > -10247) { //未知字符 return null; } else { for(int i=pyvalue.length-1;i>=0;i--){ if(asc>=pyvalue[i]){ res=pystr[i]; break; } } } //提取首字母 res=res.substring(0,1); return res; } //获取首字母的大写字母 public static String getFirstUpperLetter(String cn){ return getFirstLetter(cn).toUpperCase(); } //获取首字母 public static String getFirstLetter(String cn){ return getSpellByAscii(getChsAscii(cn.substring(0, 1))); } //获取全拼 public static String getFullSpell(String cn){ String resString=null; for(int i=0;i<cn.length();i++){ String string=cn.substring(i, i+1); resString+=getSpellByAscii(getChsAscii(string)); } return resString; } }
然后把首字母同样的列表项排在一起。在显示的仅显示第一个。
见下图
比方七号公园。七里香。七夕。。。仅仅显示七号公园中的catalog。其它两个隐藏。
列表项布局文件song_listitem.xml
详细控件代码解释能够參考: http://blog.csdn.net/xiaanming/article/details/12684155
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:descendantFocusability="afterDescendants" android:orientation="vertical" > <!-- 显示字母项 --> <TextView android:id="@+id/catalog" style="@style/catalog" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="catalog" android:visibility="gone" /> <RelativeLayout android:id="@+id/song_item" android:layout_width="match_parent" android:layout_height="60dp" android:background="@drawable/effect_list_item_bg" android:clickable="true" android:focusable="true" > <TextView android:id="@+id/song_title" style="@style/song_title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:maxEms="20" android:text="song_text" android:textSize="@dimen/text_size_medium" /> <TextView android:id="@+id/duration_tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentRight="true" android:layout_centerVertical="true" android:layout_marginRight="14dp" android:text="00:00" android:textColor="@color/darkgray" /> <TextView android:id="@+id/artist_tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_alignParentLeft="true" android:layout_margin="10dp" android:text="artist_tv" android:textAppearance="?android:attr/textAppearanceSmall" android:textColor="@color/darkgray" /> <View android:id="@+id/selected_view" android:layout_width="8dp" android:layout_height="match_parent" android:layout_alignParentLeft="true" android:layout_centerVertical="true" android:background="@color/darkorchid" android:visibility="invisible" /> </RelativeLayout> </LinearLayout>
详细控件代码解释能够參考: http://blog.csdn.net/xiaanming/article/details/12684155
三,选中歌曲特效
如今的问题是,当我点击“七号公园”,焦点却在整个listitem上,字母q和七号公园是一个总体,我们必需要屏蔽Listitem的焦点,而让焦点在song_item这个相对布局上。
我们须要在最外层布局LinearLayout加上一个属性。 android:descendantFocusability="afterDescendants",以致子控件优于viewgroup获取焦点。
android:descendantFocusability属性的值有三种:
beforeDescendants:viewgroup会优先其子类控件而获取到焦点
afterDescendants:viewgroup仅仅有当其子类控件不须要获取焦点时才获取焦点
blocksDescendants:viewgroup会覆盖子类控件而直接获得焦点
然后这个紫色的小方块并非一个背景,最開始我也想用一个背景来实现,后来參考了字母的实现方案,在选中时显示这个方块,未选中时隐藏这个方块就好了。
楼主在实现的过程中,遇到一个小问题,特此记录一下。
最開始是这样写的,比方要显示紫色方块。就在onSelecte()后,立即设置为控件的setVisibility(),后来发现把这个歌曲滑到看不见位置。然后又滑下来,发现设置的效果不起作用了。
后来思考了下。由于再把歌曲滑下来,会去调用listView的adapter的getView(),所以setVisibility()就不起作用了。建议写出以下这样。用一个selectedpos去标记选中的位置,然后在getView()设置属性。 所以选中后。刷新一下listView就好了。
//设置正在播放的音乐的视图(紫色小方块) int selectedpos=MusicManager.getInstance().getNowplaying_index(); if(position==selectedpos){ mViewHolder.selected_view.setVisibility(View.VISIBLE); }else{ mViewHolder.selected_view.setVisibility(View.INVISIBLE); }下一篇总结播放本地音乐: http://blog.csdn.net/huweigoodboy/article/details/39861539