android小项目之音乐播放器二

痛定思痛。 2023-10-16 19:31 42阅读 0赞

## Android应用开发--MP3音乐播放器代码实现（一） ##

###      需求1：将内存卡中的MP3音乐读取出来并显示到列表当中  1. 从数据库中查询所有音乐数据，保存到List集合当中，List当中存放的是Mp3Info对象 2. 迭代List集合，把每一个Mp3Info对象的所有属性，保存到Map对象当中 3. 定义一个List集合，把Map对象添加到List集合当中 4. 通过定义一个SimpleAdpter,调用setAdpter方法，将数据显示到列表当中       **\[java\]** [ view plain][view plain] [copy][view plain] [print][view plain] [?][view plain]  /\*\*  \* 用于从数据库中查询歌曲的信息，保存在List当中  \*  \* @return  \*/  public List<Mp3Info> getMp3Infos() \{  Cursor cursor = 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++) \{  Mp3Info mp3Info = new Mp3Info();  cursor.moveToNext();  long id = cursor.getLong(cursor  .getColumnIndex(MediaStore.Audio.Media.\_ID)); //音乐id  String 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  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.setDuration(duration);  mp3Info.setSize(size);  mp3Info.setUrl(url);  mp3Infos.add(mp3Info);  \}  \}  return mp3Infos;  \}  `/** * 用于从数据库中查询歌曲的信息，保存在List当中 * * @return */ public List<Mp3Info> getMp3Infos() { Cursor cursor = 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++) { Mp3Info mp3Info = new Mp3Info(); cursor.moveToNext(); long id = cursor.getLong(cursor .getColumnIndex(MediaStore.Audio.Media._ID)); //音乐id String 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 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.setDuration(duration); mp3Info.setSize(size); mp3Info.setUrl(url); mp3Infos.add(mp3Info); } } return mp3Infos; }`       **\[java\]** [ view plain][view plain] [copy][view plain] [print][view plain] [?][view plain]  /\*\*   \* 填充列表   \* @param mp3Infos   \*/  public void setListAdpter(List<Mp3Info> mp3Infos) \{  List<HashMap<String, String>> mp3list = new ArrayList<HashMap<String, String>>();  for (Iterator iterator = mp3Infos.iterator(); iterator.hasNext();) \{  Mp3Info mp3Info = (Mp3Info) iterator.next();  HashMap<String, String> map = new HashMap<String, String>();  map.put("title", mp3Info.getTitle());  map.put("Artist", mp3Info.getArtist());  map.put("duration", String.valueOf(mp3Info.getDuration()));  map.put("size", String.valueOf(mp3Info.getSize()));  map.put("url", mp3Info.getUrl());  mp3list.add(map);  \}  mAdapter = new SimpleAdapter(this, mp3list,  R.layout.music\_list\_item\_layout, new String\[\] \{ "title", "Artist", "duration" \},  new int\[\] \{ R.id.music\_title, R.id.music\_Artist, R.id.music\_duration \});  mMusiclist.setAdapter(mAdapter);  \}  `/** * 填充列表 * @param mp3Infos */ public void setListAdpter(List<Mp3Info> mp3Infos) { List<HashMap<String, String>> mp3list = new ArrayList<HashMap<String, String>>(); for (Iterator iterator = mp3Infos.iterator(); iterator.hasNext();) { Mp3Info mp3Info = (Mp3Info) iterator.next(); HashMap<String, String> map = new HashMap<String, String>(); map.put("title", mp3Info.getTitle()); map.put("Artist", mp3Info.getArtist()); map.put("duration", String.valueOf(mp3Info.getDuration())); map.put("size", String.valueOf(mp3Info.getSize())); map.put("url", mp3Info.getUrl()); mp3list.add(map); } mAdapter = new SimpleAdapter(this, mp3list, R.layout.music_list_item_layout, new String[] { "title", "Artist", "duration" }, new int[] { R.id.music_title, R.id.music_Artist, R.id.music_duration }); mMusiclist.setAdapter(mAdapter); }`       实现效果如图：  ![20130508194756502][]            需求2：点击列表的每一项，启动一个服务来播放音乐  1. 注册条目点击监听器OnItemClickListener  2. 定义一个实现OnItemClickListener接口的内部类  3. 定义一个继承Service的服务类PlayerServie            **1. 注册条目点击监听器OnItemClickListener**     **\[java\]** [ view plain][view plain] [copy][view plain] [print][view plain] [?][view plain]  mMusiclist = (ListView) findViewById(R.id.music\_list);  mMusiclist.setOnItemClickListener(new MusicListItemClickListener());  mp3Infos = getMp3Infos();  setListAdpter(getMp3Infos());  `mMusiclist = (ListView) findViewById(R.id.music_list); mMusiclist.setOnItemClickListener(new MusicListItemClickListener()); mp3Infos = getMp3Infos(); setListAdpter(getMp3Infos());`          **2. 定义一个实现OnItemClickListener接口的内部类**     **\[java\]** [ view plain][view plain] [copy][view plain] [print][view plain] [?][view plain]  private class MusicListItemClickListener implements OnItemClickListener \{  @Override  public void onItemClick(AdapterView<?> parent, View view, int position,  long id) \{  if(mp3Infos != null) \{  Mp3Info mp3Info = mp3Infos.get(position);  Log.d("mp3Info-->", mp3Info.toString());  Intent intent = new Intent();  intent.putExtra("url", mp3Info.getUrl());  intent.putExtra("MSG", AppConstant.PlayerMsg.PLAY\_MSG);  intent.setClass(MainActivity.this, PlayerService.class);  startService(intent); //启动服务  \}  \}  \}  `private class MusicListItemClickListener implements OnItemClickListener { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { if(mp3Infos != null) { Mp3Info mp3Info = mp3Infos.get(position); Log.d("mp3Info-->", mp3Info.toString()); Intent intent = new Intent(); intent.putExtra("url", mp3Info.getUrl()); intent.putExtra("MSG", AppConstant.PlayerMsg.PLAY_MSG); intent.setClass(MainActivity.this, PlayerService.class); startService(intent); //启动服务 } } }`          **3. 定义一个继承Service的服务类PlayerServie（未完善的Service类）**     **\[java\]** [ view plain][view plain] [copy][view plain] [print][view plain] [?][view plain]  package com.wwj.sb.service;  import android.annotation.SuppressLint;  import android.app.Service;  import android.content.Intent;  import android.media.MediaPlayer;  import android.media.MediaPlayer.OnPreparedListener;  import android.os.IBinder;  import com.wwj.sb.domain.AppConstant;  @SuppressLint("NewApi")  public class PlayerService extends Service \{  private MediaPlayer mediaPlayer = new MediaPlayer(); //媒体播放器对象  private String path; //音乐文件路径  private boolean isPause; //暂停状态  @Override  public IBinder onBind(Intent arg0) \{  return null;  \}  @Override  public int onStartCommand(Intent intent, int flags, int startId) \{  if(mediaPlayer.isPlaying()) \{  stop();  \}  path = intent.getStringExtra("url");  int msg = intent.getIntExtra("MSG", 0);  if(msg == AppConstant.PlayerMsg.PLAY\_MSG) \{  play(0);  \} else if(msg == AppConstant.PlayerMsg.PAUSE\_MSG) \{  pause();  \} else if(msg == AppConstant.PlayerMsg.STOP\_MSG) \{  stop();  \}  return super.onStartCommand(intent, flags, startId);  \}  /\*\*   \* 播放音乐   \* @param position   \*/  private void play(int position) \{  try \{  mediaPlayer.reset();//把各项参数恢复到初始状态  mediaPlayer.setDataSource(path);  mediaPlayer.prepare(); //进行缓冲  mediaPlayer.setOnPreparedListener(new PreparedListener(position));//注册一个监听器  \}  catch (Exception e) \{  e.printStackTrace();  \}  \}  /\*\*   \* 暂停音乐   \*/  private void pause() \{  if (mediaPlayer != null && mediaPlayer.isPlaying()) \{  mediaPlayer.pause();  isPause = true;  \}  \}  /\*\*   \* 停止音乐   \*/  private void stop()\{  if(mediaPlayer != null) \{  mediaPlayer.stop();  try \{  mediaPlayer.prepare(); // 在调用stop后如果需要再次通过start进行播放,需要之前调用prepare函数  \} catch (Exception e) \{  e.printStackTrace();  \}  \}  \}  @Override  public void onDestroy() \{  if(mediaPlayer != null)\{  mediaPlayer.stop();  mediaPlayer.release();  \}  \}  /\*\*   \*    \* 实现一个OnPrepareLister接口,当音乐准备好的时候开始播放   \*   \*/  private final class PreparedListener implements OnPreparedListener \{  private int positon;  public PreparedListener(int positon) \{  this.positon = positon;  \}  @Override  public void onPrepared(MediaPlayer mp) \{  mediaPlayer.start(); //开始播放  if(positon > 0) \{ //如果音乐不是从头播放  mediaPlayer.seekTo(positon);  \}  \}  \}  \}  `package com.wwj.sb.service; import android.annotation.SuppressLint; import android.app.Service; import android.content.Intent; import android.media.MediaPlayer; import android.media.MediaPlayer.OnPreparedListener; import android.os.IBinder; import com.wwj.sb.domain.AppConstant; @SuppressLint("NewApi") public class PlayerService extends Service { private MediaPlayer mediaPlayer = new MediaPlayer(); //媒体播放器对象 private String path; //音乐文件路径 private boolean isPause; //暂停状态 @Override public IBinder onBind(Intent arg0) { return null; } @Override public int onStartCommand(Intent intent, int flags, int startId) { if(mediaPlayer.isPlaying()) { stop(); } path = intent.getStringExtra("url"); int msg = intent.getIntExtra("MSG", 0); if(msg == AppConstant.PlayerMsg.PLAY_MSG) { play(0); } else if(msg == AppConstant.PlayerMsg.PAUSE_MSG) { pause(); } else if(msg == AppConstant.PlayerMsg.STOP_MSG) { stop(); } return super.onStartCommand(intent, flags, startId); } /** * 播放音乐 * @param position */ private void play(int position) { try { mediaPlayer.reset();//把各项参数恢复到初始状态 mediaPlayer.setDataSource(path); mediaPlayer.prepare(); //进行缓冲 mediaPlayer.setOnPreparedListener(new PreparedListener(position));//注册一个监听器 } catch (Exception e) { e.printStackTrace(); } } /** * 暂停音乐 */ private void pause() { if (mediaPlayer != null && mediaPlayer.isPlaying()) { mediaPlayer.pause(); isPause = true; } } /** * 停止音乐 */ private void stop(){ if(mediaPlayer != null) { mediaPlayer.stop(); try { mediaPlayer.prepare(); // 在调用stop后如果需要再次通过start进行播放,需要之前调用prepare函数 } catch (Exception e) { e.printStackTrace(); } } } @Override public void onDestroy() { if(mediaPlayer != null){ mediaPlayer.stop(); mediaPlayer.release(); } } /** * * 实现一个OnPrepareLister接口,当音乐准备好的时候开始播放 * */ private final class PreparedListener implements OnPreparedListener { private int positon; public PreparedListener(int positon) { this.positon = positon; } @Override public void onPrepared(MediaPlayer mp) { mediaPlayer.start(); //开始播放 if(positon > 0) { //如果音乐不是从头播放 mediaPlayer.seekTo(positon); } } } }`          以上代码实现了两个需求，显示音乐列表和实现列表点击事件启动Servic。下次会实现控制音乐播放的需求 ###

[view plain]: http://blog.csdn.net/wwj_748/article/details/8902071#
[20130508194756502]: https://img-blog.csdn.net/20130508194756502