android 5大组件的应用案例

package com.itjob; import java.io.IOException; import java.io.UnsupportedEncodingException; import android.app.Service; import android.content.Intent; import android.database.Cursor; import android.media.MediaPlayer; import android.net.Uri; import android.os.IBinder; import android.provider.MediaStore; import android.widget.Toast; public class MusicService extends Service { String[] mCursorCols = new String[] { "audio._id AS _id", // index must match IDCOLIDX below MediaStore.Audio.Media.ARTIST, MediaStore.Audio.Media.ALBUM, MediaStore.Audio.Media.TITLE, MediaStore.Audio.Media.DATA, MediaStore.Audio.Media.MIME_TYPE, MediaStore.Audio.Media.ALBUM_ID, MediaStore.Audio.Media.ARTIST_ID, MediaStore.Audio.Media.DURATION }; private MediaPlayer mMediaPlayer; private Cursor mCursor; private int mPlayPosition = 0; public static final String PLAY_ACTION = "com.itjob.music.PLAY_ACTION"; public static final String PAUSE_ACTION = "com.itjob.music.PAUSE_ACTION"; public static final String NEXT_ACTION = "com.itjob.music.NEXT_ACTION"; public static final String PREVIOUS_ACTION = "com.itjob.music.PREVIOUS_ACTION"; @Override public IBinder onBind(Intent arg0) { // TODO Auto-generated method stub return null; } @Override public void onCreate() { super.onCreate(); mMediaPlayer = new MediaPlayer(); //通过一个URI可以获取所有音频文件 Uri MUSIC_URL = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI; //大于10秒的可以看作是歌 mCursor = getContentResolver().query(MUSIC_URL, mCursorCols, "duration > 10000", null, null); } @Override public void onStart(Intent intent, int startId) { super.onStart(intent, startId); String action = intent.getAction(); if(action.equals(PLAY_ACTION)){ play(); }else if(action.equals(PAUSE_ACTION)){ pause(); }else if(action.equals(NEXT_ACTION)){ next(); }else if(action.equals(PREVIOUS_ACTION)){ previous(); } } //play the music public void play() { init(); } //暂停时，结束服务 public void pause() { super.stopSelf(); } //上一首 public void previous() { if (mPlayPosition == 0) { mPlayPosition = mCursor.getCount() - 1; } else { mPlayPosition--; } init(); } public void next() { if (mPlayPosition == mCursor.getCount() - 1) { mPlayPosition = 0; } else { mPlayPosition++; } init(); } public void init() { mMediaPlayer.reset(); String dataSource = getDataByPosition(mCursor, mPlayPosition); // String info = getInfoByPosition(mCursor, mPlayPosition); //用Toast显示歌曲信息 // Toast.makeText(getApplicationContext(), info, Toast.LENGTH_SHORT).show(); try { mMediaPlayer.setDataSource(dataSource); mMediaPlayer.prepare(); mMediaPlayer.start(); } catch (IllegalArgumentException e1) { e1.printStackTrace(); } catch (IllegalStateException e1) { e1.printStackTrace(); } catch (IOException e1) { e1.printStackTrace(); } } //根据位置来获取歌曲位置 public String getDataByPosition(Cursor c,int position){ c.moveToPosition(position); int dataColumn = c.getColumnIndex(MediaStore.Audio.Media.DATA); String data = c.getString(dataColumn); return data; } /* //获取当前播放歌曲演唱者及歌名 public String getInfoByPosition(Cursor c,int position){ c.moveToPosition(position); int titleColumn = c.getColumnIndex(MediaStore.Audio.Media.TITLE); int artistColumn = c.getColumnIndex(MediaStore.Audio.Media.ARTIST); String info = c.getString(artistColumn)+" " + c.getString(titleColumn); return info; } */ //服务结束时要释放MediaPlayer @Override public void onDestroy() { super.onDestroy(); mMediaPlayer.release(); } }