王城旧事-好记性不如烂笔头

1.在manifests.xml中添加
<service android:name=".utils.MusicService"  android:enabled="true"/>


2.新建一个音乐类

import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.Binder;
import android.os.IBinder;


/**
 * MusicService 控制后台音乐播放
 * 提供控制方法，在Activity中调用
 */
/*

public class MusicService extends Service implements MediaPlayer.OnErrorListener {
    private final IBinder mBinder = new ServiceBinder(); //在Activity 使用Ibinder 对象与 MusicService 进行交互
    MediaPlayer mediaPlayer;
    private int length = 0;

    public MusicService() {
        //这里可以执行一些初始化
    }

    public class ServiceBinder extends Binder {
        public MusicService getService() {
            return MusicService.this;
        }
    }

    @Override
    public IBinder onBind(Intent arg0) {
        return mBinder;
    }

    @Override
    public void onCreate() {
        super.onCreate();

        mediaPlayer = MediaPlayer.create(this, R.raw.bg_main);
        mediaPlayer.setOnErrorListener(this);

        if (mediaPlayer != null) {
            mediaPlayer.setLooping(true);
            mediaPlayer.setVolume(100, 100);
        }


        mediaPlayer.setOnErrorListener(new MediaPlayer.OnErrorListener() {

            public boolean onError(MediaPlayer mp, int what, int
                    extra) {

                onError(mediaPlayer, what, extra);
                return true;
            }
        });
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        mediaPlayer.start();
        return START_STICKY;
    }

    public void pauseMusic() {
        if (mediaPlayer.isPlaying()) {
            mediaPlayer.pause();
            length = mediaPlayer.getCurrentPosition();

        }
    }

    public void resumeMusic() {
        if (mediaPlayer.isPlaying() == false) {
            mediaPlayer.seekTo(length);
            mediaPlayer.start();
        }
    }

    public void stopMusic() {
        if (mediaPlayer != null) {
            mediaPlayer.stop();
            mediaPlayer.release();
            mediaPlayer = null;
        }
    }

    @Override
    public boolean stopService(Intent name) {
        mediaPlayer.stop();
        mediaPlayer.release();
        return super.stopService(name);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if (mediaPlayer != null) {
            try {
                mediaPlayer.stop();
                mediaPlayer.release();
            } finally {
                mediaPlayer = null;
            }
        }
    }

    public boolean onError(MediaPlayer mp, int what, int extra) {
        Common.showShort(this,String.valueOf(R.string.music_player_fail));
        if (mediaPlayer != null) {
            try {
                mediaPlayer.stop();
                mediaPlayer.release();
            } finally {
                mediaPlayer = null;
            }
        }
        return false;
    }

/*调用说明：
开始、暂停、继续播放、停止 音乐：
step 1：在 activity 的onCreate 中调用 doBindService 来将 service 绑定到 activity
Step 2: 通过Intent 启动service
        Intent music = new Intent();
        music.setClass(this,MusicService.class);
        startService(music);
Step 3: 在 activity中调用 pause, resume 或者 stop 来控制音乐:
        mServ.pauseMusic();
        mServ.resumeMusic();
        mServ.stopMusic();
Step 4: 在Activity 的onDestroy 中调用 doUnbindService

  以下内容写在Activity中：
*/

    private boolean mIsBound = false;
    private MusicService mServ;
    private ServiceConnection Scon =new ServiceConnection(){

        public void onServiceConnected(ComponentName name, IBinder
                binder) {
            mServ = ((MusicService.ServiceBinder)binder).getService();
        }

        public void onServiceDisconnected(ComponentName name) {
            mServ = null;
        }
    };
    void doBindService(){
        bindService(new Intent(this,MusicService.class),
                Scon,Context.BIND_AUTO_CREATE);
        mIsBound = true;
    }
    void doUnbindService()
    {
        if(mIsBound)
        {
            unbindService(Scon);
            mIsBound = false;
        }
    }