Android Alarm Manager is not working for Flutter Project App
I have installed the Android Alarm Manager plugin in my New Flutter app. I use the example code of Plugin- but it gives error in console.
Please suggest how to make android alarm manager plugins works. How do I Integrate the Dart's android_alarm_manager to the app so that users get alarm when the time they picked in the schedule reaches?
I use the code from this link: https://github.com/flutter/plugins/tree/master/packages/android_alarm_manager
////// main.dart://///////
import 'dart:isolate';
import 'package:android_alarm_manager/android_alarm_manager.dart';
import 'package:flutter/material.dart';
void printHello() {
final DateTime now = DateTime.now();
final int isolateId = Isolate.current.hashCode;
print("[$now] Hello, world! isolate=${isolateId} function='$printHello'");
}
void main() async {
final int helloAlarmID = 0;
await AndroidAlarmManager.initialize();
runApp(MaterialApp(home: Application()));
await AndroidAlarmManager.periodic(const Duration(minutes: 1), helloAlarmID, printHello);
}
class Application extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
body: Container(),
);
}
}
///////////////Application.java/////////////////////
package io.flutter.plugins.androidalarmmanagerexample;
import io.flutter.app.FlutterApplication;
import io.flutter.plugin.common.PluginRegistry;
import io.flutter.plugin.common.PluginRegistry.PluginRegistrantCallback;
import io.flutter.plugins.GeneratedPluginRegistrant;
public class Application extends FlutterApplication implements PluginRegistrantCallback {
@Override
public void onCreate() {
super.onCreate();
AlarmService.setPluginRegistrant(this);
}
@Override
public void registerWith(PluginRegistry registry) {
GeneratedPluginRegistrant.registerWith(registry);
}
}
///// When I run this code it gives error in console as given below://////
E/flutter ( 6831): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: PlatformException(error, Attempt to invoke interface method 'void io.flutter.plugin.common.PluginRegistry$PluginRegistrantCallback.registerWith(io.flutter.plugin.common.PluginRegistry)' on a null object reference, null)
E/flutter ( 6831): #0 JSONMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:149:7)
E/flutter ( 6831): #1 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:302:33)
E/flutter ( 6831): <asynchronous suspension>
E/flutter ( 6831): #2 AndroidAlarmManager.initialize (package:android_alarm_manager/android_alarm_manager.dart:76:10)
E/flutter ( 6831): <asynchronous suspension>
E/flutter ( 6831): #3 main (package:alarmdemo/main.dart:12:29)
E/flutter ( 6831): <asynchronous suspension>
E/flutter ( 6831): #4 _runMainZoned.<anonymous closure>.<anonymous closure> (dart:ui/hooks.dart:189:25)
E/flutter ( 6831): #5 _rootRun (dart:async/zone.dart:1124:13)
E/flutter ( 6831): #6 _CustomZone.run (dart:async/zone.dart:1021:19)
E/flutter ( 6831): #7 _runZoned (dart:async/zone.dart:1516:10)
E/flutter ( 6831): #8 runZoned (dart:async/zone.dart:1500:12)
E/flutter ( 6831): #9 _runMainZoned.<anonymous closure> (dart:ui/hooks.dart:180:5)
E/flutter ( 6831): #10 _startIsolate.<anonymous closure> (dart:isolate/runtime/libisolate_patch.dart:300:19)
E/flutter ( 6831): #11 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:171:12)
E/flutter ( 6831):
E/flutter ( 6831): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: MissingPluginException(No implementation found for method AlarmService.initialized on channel plugins.flutter.io/android_alarm_manager_background)
E/flutter ( 6831): #0 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:300:7)
E/flutter ( 6831): <asynchronous suspension>
E/flutter ( 6831): #1 _alarmManagerCallbackDispatcher (package:android_alarm_manager/android_alarm_manager.dart:49:12)
E/flutter ( 6831): #2 _runMainZoned.<anonymous closure>.<anonymous closure> (dart:ui/hooks.dart:189:25)
E/flutter ( 6831): #3 _rootRun (dart:async/zone.dart:1124:13)
E/flutter ( 6831): #4 _CustomZone.run (dart:async/zone.dart:1021:19)
E/flutter ( 6831): #5 _runZoned (dart:async/zone.dart:1516:10)
E/flutter ( 6831): #6 runZoned (dart:async/zone.dart:1500:12)
E/flutter ( 6831): #7 _runMainZoned.<anonymous closure> (dart:ui/hooks.dart:180:5)
E/flutter ( 6831): #8 _startIsolate.<anonymous closure> (dart:isolate/runtime/libisolate_patch.dart:300:19)
E/flutter ( 6831): #9 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:171:12)
E/flutter ( 6831):
This is my Updated Code:
/////////////main.dart//////////
void printHello() {
final DateTime now = new DateTime.now();
final int isolateId = Isolate.current.hashCode;
print("[$now] Hello, world! isolate=${isolateId}
function='$printHello'");
}
void main() async {
runApp(MaterialApp(home: Application()));
}
class Application extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
body: Container(
child: Center(
child: RaisedButton(
child: Text('Hello'),
onPressed: () {
runAlarm();
},
),
),
),
);
}
void runAlarm() {
AndroidAlarmManager.oneShot(
Duration(seconds: 10),
0,
printHello,
wakeup: true,
).then((val) => print(val));
}
static void alarmTest() {
print("test");
}
}
It does not give any Error in console but print two statements as below:
E/AlarmService(11943): Fatal: failed to find callback
I/AlarmService(11943): AlarmService has not yet started.
I also initialize the alarm manager but it gives error in console:
void runAlarm() {
AndroidAlarmManager.periodic(
Duration(seconds: 10),
0,
printHello,
wakeup: true,
).then((val) => print(val)).catchError((e) {
print(e);
});
}
Error:
E/flutter ( 6831): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: PlatformException(error, Attempt to invoke interface method 'void io.flutter.plugin.common.PluginRegistry$PluginRegistrantCallback.registerWith(io.flutter.plugin.common.PluginRegistry)' on a null object reference, null)
E/flutter ( 6831): #0 JSONMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:149:7)
E/flutter ( 6831): #1 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:302:33)
E/flutter ( 6831): <asynchronous suspension>
E/flutter ( 6831): #2 AndroidAlarmManager.initialize (package:android_alarm_manager/android_alarm_manager.dart:76:10)
E/flutter ( 6831): <asynchronous suspension>
E/flutter ( 6831): #3 main (package:alarmdemo/main.dart:12:29)
E/flutter ( 6831): <asynchronous suspension>
E/flutter ( 6831): #4 _runMainZoned.<anonymous closure>.<anonymous closure> (dart:ui/hooks.dart:189:25)
E/flutter ( 6831): #5 _rootRun (dart:async/zone.dart:1124:13)
E/flutter ( 6831): #6 _CustomZone.run (dart:async/zone.dart:1021:19)
E/flutter ( 6831): #7 _runZoned (dart:async/zone.dart:1516:10)
E/flutter ( 6831): #8 runZoned (dart:async/zone.dart:1500:12)
E/flutter ( 6831): #9 _runMainZoned.<anonymous closure> (dart:ui/hooks.dart:180:5)
E/flutter ( 6831): #10 _startIsolate.<anonymous closure> (dart:isolate/runtime/libisolate_patch.dart:300:19)
E/flutter ( 6831): #11 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:171:12)
E/flutter ( 6831):
E/flutter ( 6831): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: MissingPluginException(No implementation found for method AlarmService.initialized on channel plugins.flutter.io/android_alarm_manager_background)
E/flutter ( 6831): #0 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:300:7)
E/flutter ( 6831): <asynchronous suspension>
E/flutter ( 6831): #1 _alarmManagerCallbackDispatcher (package:android_alarm_manager/android_alarm_manager.dart:49:12)
E/flutter ( 6831): #2 _runMainZoned.<anonymous closure>.<anonymous closure> (dart:ui/hooks.dart:189:25)
E/flutter ( 6831): #3 _rootRun (dart:async/zone.dart:1124:13)
E/flutter ( 6831): #4 _CustomZone.run (dart:async/zone.dart:1021:19)
E/flutter ( 6831): #5 _runZoned (dart:async/zone.dart:1516:10)
E/flutter ( 6831): #6 runZoned (dart:async/zone.dart:1500:12)
E/flutter ( 6831): #7 _runMainZoned.<anonymous closure> (dart:ui/hooks.dart:180:5)
E/flutter ( 6831): #8 _startIsolate.<anonymous closure> (dart:isolate/runtime/libisolate_patch.dart:300:19)
E/flutter ( 6831): #9 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:171:12)
E/flutter ( 6831):
Answer
I've finally fixed this issue myself, after struggling for a couple of hours (but felt a lot longer!). The breakthrough came when I actually cloned the Flutter Plugins Github repository that contains android_alarm_manager and poked around the example code and looked at how it was laid out in an IDE, rather than looking at isolated files online.
The Readme is not very clear on what exactly to do, if you're not versed in Android Java development, but it becomes clear when you look at the working example code.
You need to drop in the Application.java file they give you in the example directory into your actual project, in the same folder as your existing MainActivity.java file. The contents should look like this:
package io.flutter.plugins.androidalarmmanagerexample;
import io.flutter.app.FlutterApplication;
import io.flutter.plugin.common.PluginRegistry;
import io.flutter.plugin.common.PluginRegistry.PluginRegistrantCallback;
import io.flutter.plugins.GeneratedPluginRegistrant;
import io.flutter.plugins.androidalarmmanager.AlarmService;
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);
}
}
As for where you need to put this file, their example it looks like this, but yours is probably in something like <your project dir>/android/app/src/main/java/com/example/<your project name>:
After doing this, you must update the package name on the first line of Application.java from package io.flutter.plugins.androidalarmmanagerexample; to match whatever package your project uses (see the first line of your existing MainActivity.java). If you don't do this, gradle doesn't find it and nothing works!
You can now follow the advice in the Readme, adding in the permissions and etc:
After importing this plugin to your project as usual, add the following to your
AndroidManifest.xmlwithin 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="io.flutter.plugins.androidalarmmanager.AlarmService"
android:permission="android.permission.BIND_JOB_SERVICE"
android:exported="false"/>
<receiver
android:name="io.flutter.plugins.androidalarmmanager.AlarmBroadcastReceiver"
android:exported="false"/>
<receiver
android:name="io.flutter.plugins.androidalarmmanager.RebootBroadcastReceiver"
android:enabled="false">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED"></action>
</intent-filter>
</receiver>
The last part is the part that most confused me. It sounds like they're being very vague, but if you did everything else exactly right earlier, it's actually precisely what you need to do.
Which must be reflected in the application's AndroidManifest.xml. E.g.:
<application
android:name=".Application"
...
Simply change your android:name to .Application, which means it will now utilise that Application.java we added previously.
That's it! Hopefully you can now run your app.