Android 12 brought several changes and one of them, that raises some questions, is the new exact alarm permission. This article is a quick guide about this new permission, showing why, how and when to implement the changes. It is the first time that I write an article in this format, so feedback is welcome. 😊

What is this permission?

The new exact alarm permission (SCHEDULE_EXACT_ALARM) was created to save system resources. Alarms that must be executed in an exact time may be triggered when the phone is on power-saving mode or Doze, making the app consumes more battery than it should.

When should I use an exact alarm?

Google recommends the usage of this alarm in two situations:

• The application is a clock or a timer app
• The app has precision events, such as calendars or reminder apps

What is the type of this permission?

The type of this permission is “Special app access”. You can find it on Settings > Apps > Special app access > Alarms & reminders. This permission is already granted at install-time. In order to revoke it, the user needs to manually go to this screen.

What happens when the user revokes this permission?

First of all, all the exact alarms already set will be deleted and will no longer work. Besides that, if any function setting an exact alarm is called, the app will crash with SecurityException.

My app uses AlarmManager, should I change anything?

It depends. If the application is using any AlarmManager method that define an exact alarm, some changes are required. The methods are:

• setAlarmClock()
• setExact()
• setExactAndAllowWhileIdle()

If the application is using AlarmManager with methods such as set(), setInexactRepeating(), setAndAllowWhileIdle() or setWindow(), no changes are required.

My app uses WorkManager, should I change anything?

No. WorkManager was created respecting all the system optimizations and there is no guarantee that it will be executed in the exact time that was set up. This new requirement applies only for exact alarms using AlarmManager.

What do I need to update in my app?

There are some steps required in order to keep using exact alarms on Android 12, as well as some precautions to maintain the stability of your application.

1. Add the new permission on AndroidManifest.xml

The first step is adding the new SCHEDULE_EXACT_ALARM permission on AndroidManifest.xml. If Android Studio did not find it, make sure that the app is compiled on API 31 (compileSdkVersion = 31).

2. Check if the permission is granted before setting alarms

Since this permission may be revoked anytime by the user, it is recommended that a verification is executed before setting any new exact alarm. For that, AlarmManager has a new method:

The canScheduleExactAlarms() returns a boolean informing if the permission is granted or not.

3. Redirect user to grant the permission

In case the verification method returns false, the recommendation is showing information to the user why this permission is important for your app and redirect them to “Special app access” screen. To do so, we can use the following Intent:

It should be noted that this Intent will not redirect the user to your app permission. The user will be redirected to the “Special app access” screen listing all the apps that may need this permission. Therefore it is a good idea to be clear to the user before redirecting them.

4. Register a BroadcastReceiver to receive the information about the permission

Another recommendation is creating a BroadcastReceiver to receive an Intent when the user grants the permission again for your application. This information is very important because, as mentioned earlier, when the user revokes the permission, all the exact alarms will be deleted. Based on this info, it is possible to set them up again.

For apps that already works with alarms, the behavior is similar when the phone is turned off: all the alarms are removed by the system and when it is turned back on, the app receives RECEIVE_BOOT_COMPLETED to reschedule them.

The BroadcastReceiver will be similar to following:

The ACTION_SCHEDULE_EXACT_ALARM_PERMISSION_STATE_CHANGED will be sent to both runtime and manifest receivers. In our example, registering it via manifest will look like: