Flutter Community: android_alarm_manager_plus

# android_alarm_manager_plus

A Flutter plugin for accessing the Android AlarmManager service, and running Dart code in the background when alarms fire.

Platform Support

Android
✔️

Getting Started

After importing this plugin to your project as usual, add the following to your AndroidManifest.xml within the <manifest></manifest> tags:

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

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

Check out our documentation website to learn more. [Plus plugins documentation](https://plus.fluttercommunity.dev/docs/overview)

Then in Dart code add:

import 'package:android_alarm_manager_plus/android_alarm_manager_plus.dart';

static void printHello() {
  final DateTime now = DateTime.now();
  final int isolateId = Isolate.current.hashCode;
  print("[$now] Hello, world! isolate=${isolateId} function='$printHello'");
}

main() async {
  final int helloAlarmID = 0;
  await AndroidAlarmManager.initialize();
  runApp(...);
  await AndroidAlarmManager.periodic(const Duration(minutes: 1), helloAlarmID, printHello);
}

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.

Flutter Android Embedding V2 (Flutter Version >= 1.12)

For the Flutter Android Embedding V2, plugins are registered with the background isolate via reflection so AlarmService.setPluginRegistrant does not need to be called.

NOTE: this plugin is not completely compatible with the V2 embedding on Flutter versions < 1.12 as the background isolate will not automatically register plugins. This can be resolved by running flutter upgrade to upgrade to the latest Flutter version.

Flutter Android Embedding V1 (DEPRECATED)

For the Flutter Android Embedding V1, the background service must be provided a callback to register plugins with the background isolate. This is done by giving the AlarmService a callback to call the application's onCreate method. See the example's Application overrides.

In particular, its Application class is as follows:

public class Application extends FlutterApplication implements PluginRegistrantCallback {
  @Override
  public void onCreate() {
    super.onCreate();
    AlarmService.setPluginRegistrant(this);
  }

  @Override
  public void registerWith(PluginRegistry registry) {
    GeneratedPluginRegistrant.registerWith(registry);
  }
}

Which must be reflected in the application's AndroidManifest.xml. E.g.:

    <application
        android:name=".Application"
        ...

Note: Not calling AlarmService.setPluginRegistrant will result in an exception being thrown when an alarm eventually fires.

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-web.flutter-io.cn/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

Important: As of January 2021, the Flutter team is no longer accepting non-critical PRs for the original set of plugins in flutter/plugins, and instead they should be submitted in this project. You can read more about this announcement here. as well as in the Flutter 2 announcement blog post.