Before using the plugin you would also need a plugin to request SCHEDULE_EXACT_ALARM permission when your app targets Android 14 and newer. Google introduced SCHEDULE_EXACT_ALARM permission in Android 12. In Android 13 it was granted by default. Since Android 14 this permission is denied by default and apps need to ask user to provide it. android_alarm_manager_plus does not provide a way to work with this permission, so be sure to handle such logic yourself. To do so you would need an additional plugin, like permission_handler.

After importing android_alarm_manager_plus plugin into your project, add the following lines to your AndroidManifest.xml file inside <manifest></manifest> tags:

<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
<uses-permission android:name="android.permission.WAKE_LOCK"/>
<!-- For apps with targetSDK 31 (Android 12) and newer  -->
<uses-permission android:name="android.permission.SCHEDULE_EXACT_ALARM"/>

Next, within the <application></application> tags, add:

<service
    android:name="dev.fluttercommunity.plus.androidalarmmanager.AlarmService"
    android:permission="android.permission.BIND_JOB_SERVICE"
    android:exported="false"/>
<receiver
    android:name="dev.fluttercommunity.plus.androidalarmmanager.AlarmBroadcastReceiver"
    android:exported="false"/>
<receiver
    android:name="dev.fluttercommunity.plus.androidalarmmanager.RebootBroadcastReceiver"
    android:enabled="false"
    android:exported="false">
    <intent-filter>
        <action android:name="android.intent.action.BOOT_COMPLETED" />
    </intent-filter>
</receiver>

Then in Dart code add:

import 'package:android_alarm_manager_plus/android_alarm_manager_plus.dart';

// It is required to annotate your callback function like this to avoid issues in release mode on Flutter >= 3.3.0
@pragma('vm:entry-point')
void printHello() {
  final DateTime now = DateTime.now();
  final int isolateId = Isolate.current.hashCode;
  print("[$now] Hello, world! isolate=${isolateId} function='$printHello'");
}

main() async {
  // Be sure to add this line if initialize() call happens before runApp()
  WidgetsFlutterBinding.ensureInitialized();

  await AndroidAlarmManager.initialize();
  runApp(...);
  final int helloAlarmID = 0;

  // Handle SCHEDULE_EXACT_ALARM permission before trying to schedule any alarm with the plugin
  // Otherwise an exception will happen. Check Note below for more information

  await AndroidAlarmManager.periodic(const Duration(minutes: 1), helloAlarmID, printHello);
}

note

If your app has targetSDK=31 (Android 12) or newer and you would like to create alarms with alarmClock=true or exact=true be aware that user or system might cancel such alarms by revoking SCHEDULE_EXACT_ALARM permission. More info can be found in the official documentation

AndroidAlarmManagerPlus checks if the permission was revoked before scheduling exact alarms, so your app won't get SecurityException, but will report the issue in logs. However, in case when user grants SCHEDULE_EXACT_ALARM permission again AndroidAlarmManagerPlus won't reschedule canceled alarms automatically, so it is up to you to handle such cases.

printHello will then run (roughly) every minute, even if the main app ends. However, printHello will not run in the same isolate as the main application. Unlike threads, isolates do not share memory and communication between isolates must be done via message passing (see more documentation on isolates here).

Using other plugins in alarm callbacks

If alarm callbacks will need access to other Flutter plugins, including the alarm manager plugin itself, it may be necessary to inform the background service how to initialize plugins depending on which Flutter Android embedding the application is using.

FAQ

Does this plugin support to invoke a method after reboot?

From the Android AlarmManager documentation:

Registered alarms are retained while the device is asleep (and can optionally wake the device up if they go off during that time), but will be cleared if it is turned off and rebooted. https://developer.android.com/reference/android/app/AlarmManager

My alarm is not firing after force stopping the app

The Android OS will not fire alarms for apps that have been force stopped.

StackOverflow response: https://stackoverflow.com/questions/11241794/alarm-set-in-app-with-alarmmanager-got-removed-when-app-force-stop

My alarm is not firing on a specific device

Likely the device is running some battery optimization software that is preventing the alarm from firing. Check out https://dontkillmyapp.com/ to find out about more about optimizations done by different vendors.

Plugin Development

Running Flutter unit tests

Run normally with flutter test from the root of the project.

Running Espresso tests

The Espresso test runs the same sample code provided in example/lib/main.dart but is run using the Flutter Espresso plugin.

Modifying the main.dart will cause this test to fail.

This test will call into the example/lib/main_espresso.dart file which will enable Flutter Driver and then calls into the main.dart.

See https://pub.dev/packages/espresso for more info on why.

To run the test, run from the example/android folder:

./gradlew app:connectedAndroidTest -Ptarget=`pwd`/../lib/main_espresso.dart

Running End-to-end Flutter Driver tests

To run the Flutter Driver tests, cd into example and run:

flutter driver test_driver/android_alarm_manager_e2e.dart