does Alarm Manager persist even after reboot?

Question

I am really new to android, I have been researching about alarms. I want to alarm if there is a birthday on that day. I've have used alarm manager. I was confused because i have read that it clears after reboot. I don't have an android phone so I'm just using the emulator.

Here's my code :

public void schedAlarm() {
    AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
    Intent intent = new Intent(this, AlarmService.class);
    pendingIntent = PendingIntent.getBroadcast(this, contact.id, intent, PendingIntent.FLAG_ONE_SHOT);
    am.setRepeating(AlarmManager.RTC, timetoAlarm, nextalarm, pendingIntent);
}

I made this BroadcastRecever in replace for AlarmSerivce Here :

public void onReceive(Context context, Intent intent) {
    nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
    CharSequence from = "It Birthday!";
    CharSequence message =" Greet your friend.";
    PendingIntent contentIntent = PendingIntent.getActivity(context, 0, new Intent(), 0);
    Notification notif = new Notification(R.drawable.ic_launcher, "Birthday", System.currentTimeMillis());
    notif.setLatestEventInfo(context, from, message, contentIntent);
    nm.notify(1, notif);
 }

is this enough??

By default, all alarms are canceled when a device shuts down.https://developer.android.com/training/scheduling/alarms#boot — AZ_, Apr 06 '20 at 10:41

Lucifer · Accepted Answer · 2012-08-20T09:11:28.017

95

A simple answer would be NO. But yes you can achieve this by creating a BroadCastReceiver which will start the Alarm while booting completes of the device.

Use <action android:name="android.intent.action.BOOT_COMPLETED" /> for trapping boot activity in BroadCastReceiver class.

You need to add above line in AndroidManifest.xml as follows,

<receiver android:name=".AutoStartUp" android:enabled="true" android:exported="false" android:permission="android.permission.RECEIVE_BOOT_COMPLETED">
     <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED" />
    </intent-filter>
    </receiver>

edited Aug 20 '12 at 09:11

answered Aug 20 '12 at 08:26

Lucifer

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Can i just change AlarmService into a BroadCastRecever? – Xelamae Aug 20 '12 at 08:29
I dont know your AlarmService file's code, so i can't say `yes`, but i suggest you to create new one, so that if anything goes wrong, you have atleast your previous work ready :) – Lucifer Aug 20 '12 at 08:30
ya, i saw, i suggest you to create a new BroadCastReceiver class. – Lucifer Aug 20 '12 at 08:52
I made a new one, and that's it. – Xelamae Aug 20 '12 at 09:01
Yes, and you need to make changes in AndroidManifest.xml , as i said in my answer. – Lucifer Aug 20 '12 at 09:09
1

@Lucifer - Does Android clear all Alarms that we have set, after rebooting? If yes, we should set them after rebooting again!? – Behzad Feb 19 '13 at 17:11
1

@Behzad, yes if the Alarms are set by code than it will surely get clear on reboot. – Lucifer Feb 20 '13 at 00:27
28

Please note that you also need to request the RECEIVE_BOOT_COMPLETED permission in your manifest. – Hal Jan 31 '14 at 18:25
2

Do I need to 're-register' all my alarms again in this receiver after I get a boot event? – Darpan Jan 28 '16 at 07:47
I tried with same thing but not work for me toast is not display after reboot phone. – Madhav_nimavat Dec 17 '16 at 09:17

score 9 · Answer 2 · answered Jun 28 '17 at 11:40

9

Yes , you can make AlarmManager to work even after rebooting. Perhaps this is the easiest way : add the below code in your AndroidManifest.xml:

<receiver android:name=".AlarmReceiver">
        <intent-filter>
            <action android:name="android.intent.action.BOOT_COMPLETED" />
            <action android:name="android.intent.action.QUICKBOOT_POWERON" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </receiver>

don't forget to include user-permission to the AndroidManifest.xml as:

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>

answered Jun 28 '17 at 11:40

Mohan Munisifreddy

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it fires automatically just after reboot even if alarm is set an hour later. – ralphgabb Oct 11 '18 at 02:56
1

Yes, Typically this would be called after a `PendingIntent` which would call `.AlarmReceiver` after a set period of time. By adding `BOOT_COMPLETED` and `QUICKBOOT_POWERON`. In the above answer `.AlarmReceiver` is called on boot (incorrect action), and the `PendingIntent` is still lost after boot. Instead an additional receiver should be called from `BOOT_COMPLETED` and `QUICKBOOT_POWERON` that re initializes the `PendingIntent` – Aaron Dougherty Oct 11 '18 at 04:41

Romy Gomes · Answer 3 · 2017-08-02T13:57:59.840

3

in some phones only adding

<action android:name="android.intent.action.Boot_COMPLETED" />

does not work you also have to add

<action android:name="android.intent.action.QUICKBOOT_POWERON" />

along with previous one

edited Aug 02 '17 at 13:57

answered Aug 02 '17 at 13:49

Romy Gomes

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Documentation of the latter one? Nothing found on developer.android.com... – Mitulát báti Apr 14 '19 at 15:28

does Alarm Manager persist even after reboot?

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