我正在开发一个Android应用程序,它启动后台任务以每x秒从用户访问一次URL(用户定义的时间间隔,默认为60)。我的结构是这样:AlarmManager.setRepeating - 服务似乎没有重复
MainActivity
这个时间表通过AlarmManager报警:
public static void scheduleAlarm(Context voContext, int viCheckInterval)
{
try {
moAlarmManager = (AlarmManager) voContext.getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(voContext, AlarmReceiver.class);
moAlarmIntent = PendingIntent.getBroadcast(voContext, 0, intent,
PendingIntent.FLAG_CANCEL_CURRENT);
Calendar time = Calendar.getInstance();
time.setTimeInMillis(System.currentTimeMillis());
time.add(Calendar.SECOND, viCheckInterval);
moAlarmManager.setRepeating(AlarmManager.RTC_WAKEUP, time.getTimeInMillis(),
time.getTimeInMillis(), moAlarmIntent);
} catch (Exception e) {
Log.e("MessageCheckAlarmHandler", e.toString());
}
}
AlarmReceiver
这是启动服务的BroadcastReceiver:
@Override
public void onReceive(Context context, Intent intent)
{
Context oAppContext = context.getApplicationContext();
if (oAppContext == null) {
oAppContext = context;
}
Intent serviceIntent = new Intent(oAppContext, MessagingService.class);
oAppContext.startService(serviceIntent);
}
的MessagingService
这就造成我们内部的记录(记录在TCP)并启动的AsyncTask称为FetchPageTask:
public class MessagingService extends Service
{
@Override
public void onCreate()
{
super.onCreate();
...
this.acquireLocks();
try {
String sCheckerUrl = oPreferences.getString("pref_server", "");
int sCheckerPort = Integer.parseInt(oPreferences.getString("pref_server_port",
"8050"));
sCheckerUrl = String.format(URL, sCheckerUrl, sCheckerPort);
this.moFetchInboxTask = new FetchPageTask(this.logger, this);
this.moFetchInboxTask.execute(sCheckerUrl);
} finally {
this.releaseLocks();
this.stopSelf();
}
}
@Override
public void onDestroy()
{
super.onDestroy();
this.logger.close();
}
@Override
public IBinder onBind(Intent intent)
{
return null;
}
/**
* Acquire a WakeLock and a WifiLock.
*/
private void acquireLocks()
{
try {
// Acquire a wake lock to prevent the device from entering "deep sleep"
PowerManager oPowerManager = (PowerManager) this.getSystemService(Context.POWER_SERVICE);
this.moWakeLock = oPowerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
this.moWakeLock.acquire();
// Acquire a WiFi lock to ensure WiFi is enabled
WifiManager wm = (WifiManager) this.getSystemService(Context.WIFI_SERVICE);
this.moWifiLock = wm.createWifiLock(WifiManager.WIFI_MODE_FULL, TAG);
this.moWifiLock.acquire();
} catch (Exception e) {
this.logger.error(TAG + "->onCreate()", "Error acquiring locks: " + e.toString());
}
}
/**
* Release our WakeLock and WifiLock.
*/
private void releaseLocks()
{
try {
this.moWakeLock.release();
this.moWifiLock.release();
} catch (Exception e) {
this.logger.error(TAG + "->releaseLocks()", e.toString());
}
}
}
FetchPageTask
这延长的AsyncTask,并做了所有获取页面和解析XML的工作。它还会添加通知,并根据需要对数据进行操作。
这一切工作正常,但不会随后运行。我知道AsyncTask的工作方式与以前使用纯Java通过ScheduledExecutorService和ScheduledFuture一样工作,并且工作正常。我决定改用AlarmManager的唯一原因是出于可维护性的目的。
啊,现在这可能是一个肯定的问题。谢谢你指出这一点。关于唤醒者,我也会研究它们。非常感谢链接! – euantorano