我正在尝试通过从Internet提取时间表并使用flutter_local_notification安排通知来设置剩余通知。我想每天在后台获取一次互联网，并安排通知（即使该应用未打开）。我正在使用background_fetch运行后台任务。运行后台任务没有问题，但是当应用未打开时flutter_local_notification无法正常工作。当应用程序处于前台或后台时，相同的代码可以正常运行。这是我收到的错误消息。
Tried to automatically register plugins with FlutterEngine (io.flutter.embedding.engine.FlutterEngine@16635ff) but could not find and invoke the GeneratedPluginRegistrant.
el dexterous.com/flutter/local_notifications)
10-30 17:46:16.097 18516 18657 E flutter : #0 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:157:7)
10-30 17:46:16.097 18516 18657 E flutter : <asynchronous suspension>
10-30 17:46:16.097 18516 18657 E flutter : #1 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:332:12)
10-30 17:46:16.097 18516 18657 E flutter : #2 AndroidFlutterLocalNotificationsPlugin.initialize (package:flutter_local_notifications/src/platform_flutter_local_notifications.dart:67
:27)
10-30 17:46:16.097 18516 18657 E flutter : #3 FlutterLocalNotificationsPlugin.initialize (package:flutter_local_notifications/src/flutter_local_notifications_plugin.dart:97:13)
10-30 17:46:16.097 18516 18657 E flutter : #4 _onBackgroundFetch (package:oxfam/ui/views/home/home_view.dart:203:12)
10-30 17:46:16.097 18516 18657 E flutter : #5 _rootRunUnary (dart:async/zone.dart:1198:47)
10-30 17:46:16.097 18516 18657 E flutter : #6 _CustomZone.runUnary (dart:async/zone.dart:1100:19)
10-30 17:46:16.097 18516 18657 E flutter : #7 _FutureListener.handleValue (dart:async/future_impl.dart:143:18)
10-30 17:46:16.097 18516 18657 E flutter : #8 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:696:45)
10-30 17:46:16.097 18516 18657 E flutter : #9 Future._propagateToListeners (dart:async/future_impl.dart:725:32)
10-30 17:46:16.097 18516 18657 E flutter : #10 Future._completeWithValue (dart:async/future_impl.dart:529:5)
10-30 17:46:16.097 18516 18657 E flutter : #11 _AsyncAwaitCompleter.complete (dart:async-patch/async_patch.dart:40:15)
10-30 17:46:16.097 18516 18657 E flutter : #12 _completeOnAsyncReturn (dart:async-patch/async_patch.dart:311:13)
10-30 17:46:16.097 18516 18657 E flutter : #13 Query.get (package:cloud_firestore/src/query.dart)
10-30 17:46:16.097 18516 18657 E flutter : #14 _rootRunUnary (dart:async/zone.dart:1198:47)
10-30 17:46:16.097 18516 18657 E flutter : #15 _CustomZone.runUnary (dart:async/zone.dart:1100:19)
10-30 17:46:16.097 18516 18657 E flutter : #16 _FutureListener.handleValue (dart:async/future_impl.dart:143:18)
10-30 17:46:16.097 18516 18657 E flutter : #17 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:696:45)
10-30 17:46:16.097 18516 18657 E flutter : #18 Future._propagateToListeners (dart:async/future_impl.dart:725:32)
10-30 17:46:16.097 18516 18657 E flutter : #19 Future._completeWithValue (dart:async/future_impl.dart:529:5)
10-30 17:46:16.097 18516 18657 E flutter : #20 _AsyncAwaitCompleter.complete (dart:async-patch/async_patch.dart:40:15)
10-30 17:46:16.097 18516 18657 E flutter : #21 _completeOnAsyncReturn (dart:async-patch/async_patch.dart:311:13)
10-30 17:46:16.097 18516 18657 E flutter : #22 MethodChannelQuery.get (package:cloud_firestore_platform_interface/src/method_channel/method_channel_query.dart)
10-30 17:46:16.097 18516 18657 E flutter : #23 _rootRunUnary (dart:async/zone.dart:1198:47)
10-30 17:46:16.097 18516 18657 E flutter : #24 _CustomZone.runUnary (dart:async/zone.dart:1100:19)
10-30 17:46:16.097 18516 18657 E flutter : #25 _FutureListener.handleValue (dart:async/future_impl.dart:143:18)
10-30 17:46:16.097 18516 18657 E flutter : #26 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:696:45)
10-30 17:46:16.097 18516 18657 E flutter : #27 Future._propagateToListeners (dart:async/future_impl.dart:725:32)
10-30 17:46:16.097 18516 18657 E flutter : #28 Future._completeWithValue (dart:async/future_impl.dart:529:5)
10-30 17:46:16.097 18516 18657 E flutter : #29 _AsyncAwaitCompleter.complete (dart:async-patch/async_patch.dart:40:15)
10-30 17:46:16.097 18516 18657 E flutter : #30 _completeOnAsyncReturn (dart:async-patch/async_patch.dart:311:13)
10-30 17:46:16.097 18516 18657 E flutter : #31 MethodChannel.invokeMapMethod (package:flutter/src/services/platform_channel.dart)
10-30 17:46:16.097 18516 18657 E flutter : #32 _rootRunUnary (dart:async/zone.dart:1198:47)
10-30 17:46:16.097 18516 18657 E flutter : #33 _CustomZone.runUnary (dart:async/zone.dart:1100:19)
10-30 17:46:16.097 18516 18657 E flutter : #34 _FutureListener.handleValue (dart:async/future_impl.dart:143:18)
10-30 17:46:16.097 18516 18657 E flutter : #35 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:696:45)
10-30 17:46:16.097 18516 18657 E flutter : #36 Future._propagateToListeners (dart:async/future_impl.dart:725:32)
10-30 17:46:16.097 18516 18657 E flutter : #37 Future._completeWithValue (dart:async/future_impl.dart:529:5)
10-30 17:46:16.097 18516 18657 E flutter : #38 _AsyncAwaitCompleter.complete (dart:async-patch/async_patch.dart:40:15)
10-30 17:46:16.097 18516 18657 E flutter : #39 _completeOnAsyncReturn (dart:async-patch/async_patch.dart:311:13)
10-30 17:46:16.097 18516 18657 E flutter : #40 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart)
10-30 17:46:16.097 18516 18657 E flutter : #41 _rootRunUnary (dart:async/zone.dart:1198:47)
10-30 17:46:16.097 18516 18657 E flutter : #42 _CustomZone.runUnary (dart:async/zone.dart:1100:19)
10-30 17:46:16.097 18516 18657 E flutter : #43 _FutureListener.handleValue (dart:async/future_impl.dart:143:18)
10-30 17:46:16.097 18516 18657 E flutter : #44 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:696:45)
10-30 17:46:16.097 18516 18657 E flutter : #45 Future._propagateToListeners (dart:async/future_impl.dart:725:32)
10-30 17:46:16.097 18516 18657 E flutter : #46 Future._completeWithValue (dart:async/future_impl.dart:529:5)
10-30 17:46:16.097 18516 18657 E flutter : #47 Future._asyncCompleteWithValue.<anonymous closure> (dart:async/future_impl.dart:567:7)
10-30 17:46:16.097 18516 18657 E flutter : #48 _rootRun (dart:async/zone.dart:1190:13)
10-30 17:46:16.097 18516 18657 E flutter : #49 _CustomZone.run (dart:async/zone.dart:10
10-30 17:46:16.099 18516 18657 E flutter : [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: MissingPluginException(No implementation found for method show on channel dex
terous.com/flutter/local_notifications)
10-30 17:46:16.099 18516 18657 E flutter : #0 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:157:7)
10-30 17:46:16.099 18516 18657 E flutter : <asynchronous suspension>
10-30 17:46:16.099 18516 18657 E flutter : #1 MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:332:12)
10-30 17:46:16.099 18516 18657 E flutter : #2 AndroidFlutterLocalNotificationsPlugin.show (package:flutter_local_notifications/src/platform_flutter_local_notifications.dart:137:21)
10-30 17:46:16.099 18516 18657 E flutter : #3 FlutterLocalNotificationsPlugin.show (package:flutter_local_notifications/src/flutter_local_notifications_plugin.dart:136:13)
10-30 17:46:16.099 18516 18657 E flutter : #4 _showNotificationWithDefaultSound (package:oxfam/ui/views/home/home_view.dart:231:14)
10-30 17:46:16.099 18516 18657 E flutter : #5 _onBackgroundFetch (package:oxfam/ui/views/home/home_view.dart:204:7)
10-30 17:46:16.099 18516 18657 E flutter : #6 _rootRunUnary (dart:async/zone.dart:1198:47)
10-30 17:46:16.099 18516 18657 E flutter : #7 _CustomZone.runUnary (dart:async/zone.dart:1100:19)
10-30 17:46:16.099 18516 18657 E flutter : #8 _FutureListener.handleValue (dart:async/future_impl.dart:143:18)
10-30 17:46:16.099 18516 18657 E flutter : #9 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:696:45)
10-30 17:46:16.099 18516 18657 E flutter : #10 Future._propagateToListeners (dart:async/future_impl.dart:725:32)
10-30 17:46:16.099 18516 18657 E flutter : #11 Future._completeWithValue (dart:async/future_impl.dart:529:5)
10-30 17:46:16.099 18516 18657 E flutter : #12 _AsyncAwaitCompleter.complete (dart:async-patch/async_patch.dart:40:15)
10-30 17:46:16.099 18516 18657 E flutter : #13 _completeOnAsyncReturn (dart:async-patch/async_patch.dart:311:13)
10-30 17:46:16.099 18516 18657 E flutter : #14 Query.get (package:cloud_firestore/src/query.dart)