为什么我的服务在其活动被销毁后不起作用？

Question

我有一个MainActivity和一个DownloadService。在MainActivity被破坏之后，DownloadService似乎被冻结了。我没有看到任何进展。当我去设置＆gt;管理应用程序＆gt;运行服务，我不再在运行列表中看到我的服务，但是，我也没有看到来自logcat的[onDestroy]。应该是什么问题？

public class DownloadService extends Service {

    public static final String  ACTION          = "action";
    public static final int     ACTION_DOWNLOAD = 0;
    private NotificationManager notificationManager;
    private Notification        notification;
    private final int           NOTIFICATION_ID = 1;

    @Override
    public void onCreate() {
        super.onCreate();
        notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        notification = new Notification();
    }

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

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        int action = intent.getIntExtra(ACTION, ACTION_DOWNLOAD);
        switch (action) {
            case ACTION_DOWNLOAD:
                startDownload(intent);
                break;
        }
        return START_NOT_STICKY;
    }

    @Override
    public void onLowMemory() {
        super.onLowMemory();
        Log.i("leapkh", "[onLowMemory]");
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.i("leapkh", "[onDestroy]");
    }

    private void startDownload(Intent intent) {
        String fileUrl = intent.getIntExtra(FILE_URL, "");
        FileDownloadAsyncTask task = new FileDownloadAsyncTask(fileUrl);
        task.execute();
    }

    private class FileDownloadAsyncTask extends AsyncTask<Void, Integer, Boolean> {

        private String     fileUrl;

        public FileDownloadAsyncTask(String fileUrl) {
            this.fileUrl = fileUrl;
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            startNotification(station);
        }

        @Override
        protected Boolean doInBackground(Void... params) {
            try {
                URL url = new URL(fileUrl);
                URLConnection conection = url.openConnection();
                conection.connect();
                int fileLength = conection.getContentLength();

                InputStream input = new BufferedInputStream(url.openStream(), 8192);

                String fileName = FileManager.getDownloadFileName(fileUrl);
                OutputStream output = new FileOutputStream(fileName);

                byte data[] = new byte[1024];

                long total = 0;
                int count, tmpPercentage = 0;
                while ((count = input.read(data)) != -1) {
                    total += count;
                    output.write(data, 0, count);
                    int percentage = (int) ((total * 100) / fileLength);
                    if (percentage > tmpPercentage) {
                        publishProgress(percentage);
                        tmpPercentage = percentage;
                    }
                }

                output.flush();
                output.close();
                input.close();
                return true;
            }
            catch (Exception e) {
                Log.i("leapkh", "[Download Error]: " + e.getMessage());
                return false;
            }
        }

        @Override
        protected void onProgressUpdate(Integer... values) {
            super.onProgressUpdate(values);
            int percentage = values[0];
            updateNotification(station, percentage);
        }

        @Override
        protected void onPostExecute(Boolean result) {
            super.onPostExecute(result);
            Log.i("leapkh", "Download finished: " + result);
            completeNotification(station, result);
            stopSelf();
        }

        private void startNotification(Station station) {
            int icon = android.R.drawable.stat_sys_download;
            CharSequence tickerText = "Start downloading...";
            long when = System.currentTimeMillis();
            notification = new Notification(icon, tickerText, when);
            String contentTitle = "Downloading from " + fileUrl;
            CharSequence contentText = "0%";
            Intent notificationIntent = new Intent();
            PendingIntent contentIntent = PendingIntent.getActivity(DownloadService.this, 0, notificationIntent, 0);
            notification.setLatestEventInfo(DownloadService.this, contentTitle, contentText, contentIntent);
            notification.flags = Notification.FLAG_ONGOING_EVENT;
            notificationManager.notify(NOTIFICATION_ID, notification);
        }

        private void updateNotification(Station station, int percentage) {
            String contentTitle = "Downloading from " + fileUrl;
            CharSequence contentText = percentage + "%";
            Intent notificationIntent = new Intent();
            PendingIntent contentIntent = PendingIntent.getActivity(DownloadService.this, 0, notificationIntent, 0);
            notification.setLatestEventInfo(DownloadService.this, contentTitle, contentText, contentIntent);
            notificationManager.notify(NOTIFICATION_ID, notification);
        }

        private void completeNotification(Station station, boolean success) {
            String contentTitle = "Downloaded from " + fileUrl;
            Intent notificationIntent = new Intent();
            PendingIntent contentIntent = PendingIntent.getActivity(DownloadService.this, 0, notificationIntent, 0);
            String statusText = success ? "Completed" : "Fail";
            notification.icon = success ? android.R.drawable.stat_sys_download_done : android.R.drawable.stat_notify_error;
            notification.flags = Notification.FLAG_AUTO_CANCEL;
            notification.setLatestEventInfo(DownloadService.this, contentTitle, statusText, contentIntent);
            notificationManager.notify(NOTIFICATION_ID, notification);
        }

    }
}