Android service和IntentService使用

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（IntentService在执行时会开启工作线程执行耗时操作，具体在onHandleIntent方法中，但是service不行）

1：IntentService onHandleIntent（）方法中执行耗时任务：
//创建IntentService

public class MyService extends IntentService {    public MyService() {        super("workThread");    }    public void onCreate() {        super.onCreate();    }    public void onDestroy() {        super.onDestroy();    }    public int onStartCommand(Intent intent, int flags, int startId) {        return super.onStartCommand(intent, flags, startId);    }    protected void onHandleIntent(Intent intent) {        String path = intent.getStringExtra("path");        for (int i = 1; i <= 3; i++) {            Log.i("info", Thread.currentThread().getName() + "线程中执行任务：" + path+ ",i=" + i);            try {                Thread.sleep(1000);            } catch (InterruptedException e) {                e.printStackTrace();            }        }    }}

//Activity中启动service并传递数据：

String path = "img/" + new Random().nextInt(100000) + ".jpg";        Intent intent = new Intent(this, MyService.class);        intent.putExtra("path", path);        startService(intent);

2：IntentService onHandleIntent（）方法中执行耗时下载任务：
//创建IntentService

public class MusicService extends IntentService {    public void onCreate() {    ......    }    protected void onHandleIntent(Intent intent) {    // 从intent中获取音乐下载路径        String path = intent.getStringExtra("path");        // 下载        File savePath = new File("/mnt/sdcard/" + path);        if (savePath.exists()) {            Message msg = Message.obtain();            msg.what = MSG_TAG_FILE_EXISTS;            msg.obj = savePath;            handler.sendMessage(msg);            return;        }        ......    }}

//Activity中启动service并传递数据：

Intent intent = new Intent(this, MusicService.class);            intent.putExtra("path", m.getMusicPath());            startService(intent);

3：service中可以自己开启工作线程执行耗时任务并发送广播通知并在UI的广播接收处理器更新UI：
//继承service：

public class MusicPlayService extends Service {    public void play() {}    public void pause() {}    public void previous() {}    public void next() {}    public void seekTo(int position) {    ..............    / 创建工作线程并发送广播.        isLoop = true;        needUpdate = true;        thread = new Thread() {            public void run() {                while (isLoop) {                    if (needUpdate && player.isPlaying()) {                        // 发送更新进度条广播.让滚动条动起来.在这里发广播是因为播放引起的滚动条移动就是在这里发生的.                        Intent intent = new Intent(                                GlobalUtils.ACTION_UPDATE_PROGRESS);                        intent.putExtra(GlobalUtils.EXTRA_PROGRESS, player                                .getCurrentPosition());                        intent.putExtra(GlobalUtils.EXTRA_DURATION, player                                .getDuration());                        intent.putExtra(GlobalUtils.EXTRA_MUSIC_NAME, app                                .getMusics().get(app.getCurrentIndex())                                .getName());                        sendBroadcast(intent);                        try {                            sleep(1000);                        } catch (InterruptedException e) {                            e.printStackTrace();                        }                    } else {                        synchronized (this) {                            try {                                wait();                            } catch (InterruptedException e) {                                e.printStackTrace();                            }                        }                    }                }            }        };        thread.start();    }}

//在MusicPlayerActivity启动MusicPlayService：

Intent intent = new Intent(this, MusicPlayService.class);        startService(intent);// 启动服务.

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