Alarmmanager not firing first alarm if device is off

Question

I am using alarm manger to set broadcast on 2am every day. Alarm manager working fine in normal scenarios but it failing in below scenario.

1. I am scheduling alarm manager @1am, change the time to 1.58am and switch off the device and switch on the phone after 5mins(ie 2.03am). In this scenario my alarm is not triggering for same day and every other days.

Can some one help me with this scenario

//Alarm manager
//timeToTwoAm is calculate time to 2AM from current time
alarmMgr.setInexactRepeating(AlarmManager.RTC_WAKEUP,timeToTwoAm,
            AlarmManager.INTERVAL_DAY, alarmIntent);

Answer 1

Your alarms will not be persisted. After a reboot all your registered alarms are removed.

2 solutions would be helpful:

1. Register a BOOT_COMPLETED broadcast receiver:

AndroidManifest.xml

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<receiver android:name=".notification.alarm.OnBootReceiver">
     <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED" />
     </intent-filter>
</receiver> 

And in your OnBootReceiver simply register your alarms at AlarmManager again.

2. Use JobScheduler-API (>= API 21) or GcmNetworkManager (PlayServices)

Depending on your use case it would also be possible to use the new GcmNetworkMaanger, which allows persisting a Job during reboot.

Add Service to your Manifest:

  <service
     android:name=".LoadWeatherService"
     android:exported="true" android:permission="com.google.android.gms.permission.BIND_NETWORK_TASK_SERVICE">
     <intent-filter>
        <action android:name="com.google.android.gms.gcm.ACTION_TASK_READY" />
     </intent-filter>
  </service>

In your service declare the things to do:

public class LoadWeatherService extends GcmTaskService {

   public void onInitializeTasks() { 
     super.onInitializeTasks();
     // Reregister your Job after update of Google Play Services
   }

   @Override
   public int onRunTask(TaskParams taskParams) {
     // Do your stuff
     return GcmNetworkManager.RESULT_SUCCESS;
   }
}

Subscribe your Job

     String tag = "myperiodicTask";
     PeriodicTask periodicTask = new PeriodicTask.Builder().setService(LoadWeatherService.class)
           .setRequiredNetwork(Task.NETWORK_STATE_CONNECTED).setPeriod(60L).setFlex(10L)
           .setTag(tag).setPersisted(true).build();
     GcmNetworkManager.getInstance(this).schedule(periodicTask);

Please notice: This is only a sample from my app, you have to adjust this regarding your needs.

Further Reading about GcmNetworkManager: https://developers.google.com/cloud-messaging/network-manager