過(guò)年前我已經(jīng)做過(guò)一個(gè)android版音樂(lè)播放器， 模仿音樂(lè)播放器項(xiàng)目 ，這個(gè)播放器基本功能已經(jīng)實(shí)現(xiàn)，但是最大的問(wèn)題是播放代碼放在了activity中處理的，當(dāng)推出音樂(lè)播放界面的時(shí)候，音樂(lè)是需要繼續(xù)播放，當(dāng)帶過(guò)來(lái)電話時(shí)音樂(lè)需要暫停，打完電話繼續(xù)播放，所以以前的版本還是有很大問(wèn)題的，今天決定一步一步實(shí)現(xiàn)一個(gè)功能齊全的播放器，把播放控制代碼放在service中。

首先來(lái)實(shí)現(xiàn)這樣一個(gè)簡(jiǎn)單的界面：

新建一個(gè)android項(xiàng)目，如圖所示：

把項(xiàng)目中用到的圖片拷貝到drawable目錄下，編寫(xiě)main.xml

<?xml version="1.0" encoding="utf-8"?> <TabHost xmlns:android="http://schemas.android.com/apk/res/android" android:id="@android:id/tabhost" android:layout_width="fill_parent" android:layout_height="fill_parent" > <LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" android:padding="5dp" > <TabWidget android:id="@android:id/tabs" android:layout_width="fill_parent" android:layout_height="wrap_content" /> <FrameLayout android:id="@android:id/tabcontent" android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="5dp" /> </LinearLayout> </TabHost>
編寫(xiě)MainActivity類

public class MainActivity extends TabActivity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); setContentView(R.layout.main); Resources res = getResources(); TabHost tabHost = getTabHost(); TabHost.TabSpec spec; Intent intent; intent = new Intent().setClass(this, ListActivity.class); spec = tabHost.newTabSpec("音樂(lè)").setIndicator("音樂(lè)", res.getDrawable(R.drawable.item)) .setContent(intent); tabHost.addTab(spec); intent = new Intent().setClass(this, ArtistsActivity.class); spec = tabHost.newTabSpec("藝術(shù)家").setIndicator("藝術(shù)家", res.getDrawable(R.drawable.artist)) .setContent(intent); tabHost.addTab(spec); intent = new Intent().setClass(this, AlbumsActivity.class); spec = tabHost.newTabSpec("專輯").setIndicator("專輯", res.getDrawable(R.drawable.album)) .setContent(intent); tabHost.addTab(spec); intent = new Intent().setClass(this, SongsActivity.class); spec = tabHost.newTabSpec("最近播放").setIndicator("最近播放", res.getDrawable(R.drawable.album)) .setContent(intent); tabHost.addTab(spec); tabHost.setCurrentTab(0); } } 注意這里要繼承的是TabActivity，關(guān)于TabHost的用法不做過(guò)多介紹，官網(wǎng)有。最后分別建立其他用到的activity和使用的xml布局文件，不要忘記在manifest中注冊(cè)，

這樣上面的主界面就完成了。

下面看一下怎么遍歷音樂(lè)文件，通過(guò)listview展現(xiàn)到界面上，

在相應(yīng)目錄下建立MusicList類，這是一個(gè)普通類，為了加載音樂(lè)文件

public class MusicList { public static List<Music> getMusicData(Context context){ List<Music> musicList=new ArrayList<Music>(); ContentResolver cr=context.getContentResolver(); if(cr!=null){ //獲取所有歌曲 Cursor cursor=cr.query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, null, null,null, MediaStore.Audio.Media.DEFAULT_SORT_ORDER); if(null==cursor){ return null; } if(cursor.moveToFirst()){ do{ Music m=new Music(); String title=cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.TITLE)); String singer=cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ARTIST)); if("<unknown>".equals(singer)){ singer="未知藝術(shù)家"; } String album=cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM)); long size=cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media.SIZE)); long time=cursor.getLong(cursor.getColumnIndex(MediaStore.Audio.Media.DURATION)); String url=cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DATA)); String name=cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DISPLAY_NAME)); m.setTitle(title); m.setSinger(singer); m.setAlbum(album); m.setSize(size); m.setTime(time); m.setUrl(url); m.setName(name); musicList.add(m); }while(cursor.moveToNext()); } } return musicList; } } 這里是通過(guò)ContentResolver得到的音樂(lè)信息，因?yàn)橄到y(tǒng)為了便于應(yīng)用程序間音樂(lè)信息的共享，提供了ContentProvder，所以我就沒(méi)有遍歷SD卡下的音樂(lè)文件。
Music類：

public class Music { private String title; private String singer; private String album; private String url; private long size; private long time; private String name; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getSinger() { return singer; } public void setSinger(String singer) { this.singer = singer; } public String getAlbum() { return album; } public void setAlbum(String album) { this.album = album; } public String getUrl() { return url; } public void setUrl(String url) { this.url = url; } public long getSize() { return size; } public void setSize(long size) { this.size = size; } public long getTime() { return time; } public void setTime(long time) { this.time = time; } } 因?yàn)橐玫阶远x適配器，所以在layout下先建立一個(gè)和適配器匹配的xml

<?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="wrap_content" android:layout_marginTop="2dip" android:background="#00000000" android:orientation="horizontal" > <ImageView android:id="@+id/music_item_image" android:layout_width="40dp" android:layout_height="40dp" android:layout_gravity="center" android:background="@drawable/item" android:paddingRight="10dip" /> <LinearLayout android:layout_width="fill_parent" android:layout_height="60dip" android:layout_weight="1" android:layout_marginLeft="3dp" android:gravity="center_vertical" android:orientation="vertical" > <TextView android:id="@+id/music_item_name" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_gravity="center_vertical" android:textColor="#ffffff" android:textSize="18dp" android:text="依然愛(ài)你" android:textStyle="bold" /> <TextView android:id="@+id/music_item_singer" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_gravity="center_vertical" android:layout_marginTop="5dip" android:textColor="#ffffff" android:text="王力宏" android:textSize="12dp" /> </LinearLayout> <TextView android:id="@+id/music_item_time" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:paddingRight="5dip" android:text="03:42" android:textColor="#ffffff" /> </LinearLayout> 接下來(lái)是自定義的適配器MusicAdapter

public class MusicAdapter extends BaseAdapter { private List<Music> listMusic; private Context context; public MusicAdapter(Context context,List<Music> listMusic){ this.context=context; this.listMusic=listMusic; } public void setListItem(List<Music> listMusic){ this.listMusic=listMusic; } @Override public int getCount() { // TODO Auto-generated method stub return listMusic.size(); } @Override public Object getItem(int arg0) { // TODO Auto-generated method stub return listMusic.get(arg0); } @Override public long getItemId(int position) { // TODO Auto-generated method stub return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { // TODO Auto-generated method stub if(convertView==null){ convertView=LayoutInflater.from(context).inflate(R.layout.music_item, null); } Music m=listMusic.get(position); //音樂(lè)名 TextView textMusicName=(TextView) convertView.findViewById(R.id.music_item_name); textMusicName.setText(m.getName()); //歌手 TextView textMusicSinger=(TextView) convertView.findViewById(R.id.music_item_singer); textMusicSinger.setText(m.getSinger()); //持續(xù)時(shí)間 TextView textMusicTime=(TextView) convertView.findViewById(R.id.music_item_time); textMusicTime.setText(toTime((int)m.getTime())); return convertView; } /** * 時(shí)間格式轉(zhuǎn)換 * @param time * @return */ public String toTime(int time) { time /= 1000; int minute = time / 60; int hour = minute / 60; int second = time % 60; minute %= 60; return String.format("%02d:%02d", minute, second); } } 時(shí)間格式的轉(zhuǎn)換是我從網(wǎng)上找到的，直接調(diào)用toTime方法能得到格式化后的時(shí)間了。

最后是在ListActivity添加適配器：

public class ListActivity extends Activity { private ListView listView; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.listmusic); listView= (ListView) this.findViewById(R.id.listAllMusic); List<Music> listMusic=MusicList.getMusicData(getApplicationContext()); MusicAdapter adapter=new MusicAdapter(this, listMusic); listView.setAdapter(adapter); } }
這樣音樂(lè)文件就會(huì)加載上來(lái)了，看看效果吧：

一步一步實(shí)現(xiàn)音樂(lè)播放器