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): 

from Android Alarm Manager is not working for Flutter Project App