闹钟服务在手机的省电模式下不起作用

Question

I have a app which using alarm service.Using the alarm service i am setting

PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0,
                new Intent("com.mindedges.pkg.intent.action.NEW_HOUR"),
                PendingIntent.FLAG_UPDATE_CURRENT);

alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, AlarmSheduleHelper
                .getImmediateNextHour().getTimeInMillis(),
                AlarmManager.INTERVAL_HOUR, pendingIntent);

And then there is a receiver for this and then it plays some sound.

Evertthing works fine for on my phone and with most of the users , but some customers complain. " most of the time app fails to show alarm and Its either few minutes late or only when I press power button to unlock the phone"

NOTE that this customer have turned on power saver and have have also included the app to be active on standby mode

What could be the possible reason?Does alarm service not work in power saver mode?

Related post : Android AlarmManager.set(...): notification never received when battery low

Answer 1

I've empirically found that the timing for repeating alarms to be wildly unpredictable. For instance, when I've asked for a 35 minute period, I'll get some alarms at about 35 minutes intervals, some hours apart, and some within a few minutes of each other.

I've found it much more predictable to just ask for a one-shot alarm and then resubmit a new one each time the alarm fires.

That approach has apparently become a Google recommendation. The AlarmManager page now has the following added to the description of SetRepeating: "Note: as of API 19, all repeating alarms are inexact. If your application needs precise delivery times then it must use one-time exact alarms, rescheduling each time as described above. Legacy applications whose targetSdkVersion is earlier than API 19 will continue to have all of their alarms, including repeating alarms, treated as exact."

Answer 2

I work on an application that heavily relies on reminders to notify users when to take their medication. Samsung devices that have PowerSave mode enabled will consistently not fire alarms at the correct time . I have seen instances where it fires one hour early. So for example users that want to be reminded at 8:00am to take there medication receive notifications at 7:00am.

Note: It doesn't matter how you set it. As usual Samsung does their own thing and all logic goes out the window.

Basically, ensure that the trigger time that was set is close enough to the current time:

public class AlarmReceiver extends BroadcastReceiver {

  @Override public void onReceive(
      final Context context,
      final Intent intent) {

    // Sanity check on the received intent.
    if ((intent == null) || (intent.getAction() == null)) {
      Log.v(TAG, "Alarm received but the extra doesn't contain valid informations");
      return;
    }

      if (!validAlarmReceived(alarm)) {
        //try to set alarm again, use the same request code to cancel the pending intent
        AlarmManager.rescheduleCurrentAlarm(alarm, context);
        return;
      }
    }
  }

  /**
   * Sanity check to see if alarm has been prematurely triggered
   * due to odd behavior with PowerSave on some devices.
   */
  private boolean validAlarmReceived(
      final Alarm alarm) {

    if (alarm.isSnoozed()) {
      //avoid time check for snoozed alarms
      return true;
    }

    final long alarmMillis = alarm.getCurrentTriggerTime();
    final long currentMillis = System.currentTimeMillis();
    final long difference = (currentMillis - alarmMillis);
    final long THRESHOLD = TimeUnit.MINUTES.toMillis(1);

    // Allow the notification to show under the following scenarios:
    // 1. The alarm triggered late (i.e. current millis > alarm millis)
    // 2. OR the alarm triggered within the threshold value
    if (difference > 0 || Math.abs(difference) < THRESHOLD) {
      return true;

    } else {
      // otherwise reschedule the alarm
      return false;
    }
  }
}