Flutter 工作管理器返回“工作人员结果失败 [id=XXXXxXXXXXXXXXX 标签= be.tramckrijte.workmanager.BackgroundWorker ]”
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【中文标题】Flutter 工作管理器返回“工作人员结果失败 [id=XXXXxXXXXXXXXXX 标签= be.tramckrijte.workmanager.BackgroundWorker ]”【英文标题】：Flutter work-manager returns "Worker result FAILURE for Work [ id=XXXXXxXXXXxXXXX tags= be.tramckrijte.workmanager.BackgroundWorker ]"Flutter 工作管理器返回“工作人员结果失败 [id=XXXXxXXXXXXXXXX 标签= be.tramckrijte.workmanager.BackgroundWorker ]” 【发布时间】：2021-06-21 23:54:18 【问题描述】：我正在构建一个通知用户祈祷时间的应用程序。我正在使用 adhan 包来计算时间并将其保存在共享首选项中。由于祈祷时间每 24 小时更改一次，因此我使用 workmanager 获取该特定时间的祈祷时间，并每 20 小时将其保存在共享偏好中。但是我正面临这个问题，有没有其他或更好的方法可以实现这一目标。
Launching lib/main.dart on ASUS X00T in debug mode...
✓ Built build/app/outputs/flutter-apk/app-debug.apk.
Connecting to VM Service at ws://127.0.0.1:44753/d5gE32RyvC4=/ws
I/.example.notif(14281): Waiting for a blocking GC ProfileSaver
E/flutter (14281): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: Invalid argument(s) (input): Must not be null
[38;5;244mE/flutter (14281): #0 _RegExp.firstMatch (dart:core-patch/regexp_patch.dart:221:24)[39;49m
[38;5;244mE/flutter (14281): #1 DateTime.parse (dart:core/date_time.dart:266:23)[39;49m
[38;5;248mE/flutter (14281): #2 PrayerTime.getFajr[39;49m
E/flutter (14281): <asynchronous suspension>
[38;5;248mE/flutter (14281): #3 _GetPrayersPageState.loalData[39;49m
E/flutter (14281): <asynchronous suspension>
E/flutter (14281):
E/cutils-trace(14281): Error opening trace file: No such file or directory (2)
I/flutter (14281): getAndSavePrayerscallbackDispatcher
I/flutter (14281): 2021-03-25 13:07:32.419749+0530
I/flutter (14281): 2021-03-25 12:45:00.000+0530
I/flutter (14281): 2021-03-25 20:04:00.000+0530
I/flutter (14281): 2021-03-25 17:08:00.000+0530
I/flutter (14281): 2021-03-25 20:04:00.000+0530
E/flutter (14281): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: NoSuchMethodError: The method 'zonedSchedule' was called on null.
E/flutter (14281): Receiver: null
E/flutter (14281): Tried calling: zonedSchedule(0, "Title", "Body", Instance of 'TZDateTime', Instance of 'NotificationDetails', androidAllowWhileIdle: true, uiLocalNotificationDateInterpretation: Instance of 'UILocalNotificationDateInterpretation')
[38;5;244mE/flutter (14281): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:54:5)[39;49m
[38;5;248mE/flutter (14281): #1 NotificationManager.zonedNotification.<anonymous closure>[39;49m
[38;5;248mE/flutter (14281): #2 NotificationManager.zonedNotification.<anonymous closure>[39;49m
[38;5;244mE/flutter (14281): #3 List.forEach (dart:core-patch/growable_array.dart:403:8)[39;49m
[38;5;248mE/flutter (14281): #4 NotificationManager.zonedNotification[39;49m
E/flutter (14281): <asynchronous suspension>
[38;5;248mE/flutter (14281): #5 callbackDispatcher.<anonymous closure>[39;49m
E/flutter (14281): <asynchronous suspension>
[38;5;244mE/flutter (14281): #6 MethodChannel._handleAsMethodCall[39;49m
E/flutter (14281): <asynchronous suspension>
[38;5;244mE/flutter (14281): #7 _DefaultBinaryMessenger.handlePlatformMessage[39;49m
E/flutter (14281): <asynchronous suspension>
E/flutter (14281):
I/chatty (14281): uid=10412(com.example.notify) 2.ui identical 3 lines
E/flutter (14281): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: NoSuchMethodError: The method 'zonedSchedule' was called on null.
E/flutter (14281): Receiver: null
E/flutter (14281): Tried calling: zonedSchedule(0, "Title", "Body", Instance of 'TZDateTime', Instance of 'NotificationDetails', androidAllowWhileIdle: true, uiLocalNotificationDateInterpretation: Instance of 'UILocalNotificationDateInterpretation')
[38;5;244mE/flutter (14281): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:54:5)[39;49m
[38;5;248mE/flutter (14281): #1 NotificationManager.zonedNotification.<anonymous closure>[39;49m
[38;5;248mE/flutter (14281): #2 NotificationManager.zonedNotification.<anonymous closure>[39;49m
[38;5;244mE/flutter (14281): #3 List.forEach (dart:core-patch/growable_array.dart:403:8)[39;49m
[38;5;248mE/flutter (14281): #4 NotificationManager.zonedNotification[39;49m
E/flutter (14281): <asynchronous suspension>
[38;5;248mE/flutter (14281): #5 callbackDispatcher.<anonymous closure>[39;49m
E/flutter (14281): <asynchronous suspension>
[38;5;244mE/flutter (14281): #6 MethodChannel._handleAsMethodCall[39;49m
E/flutter (14281): <asynchronous suspension>
[38;5;244mE/flutter (14281): #7 _DefaultBinaryMessenger.handlePlatformMessage[39;49m
E/flutter (14281): <asynchronous suspension>
E/flutter (14281):
I/WM-WorkerWrapper(14281): Worker result FAILURE for Work [ id=0a8091e2-1677-4fc9-9fbd-79468e004d97, tags= be.tramckrijte.workmanager.BackgroundWorker ]
main.dart
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:notify/local_notification/manage_notification.dart';
import 'package:notify/prayer_times.dart';
import 'package:workmanager/workmanager.dart';
import 'package:timezone/timezone.dart' as tz;
const String uniqueName = "getPrayers";
const String taskName = "getAndSavePrayers";
void main()
WidgetsFlutterBinding.ensureInitialized();
Workmanager.initialize(callbackDispatcher, isInDebugMode: true);
Workmanager.registerPeriodicTask(uniqueName, taskName,
initialDelay: Duration(minutes: 1),
frequency: Duration(hours: 20),
constraints: Constraints(
networkType: NetworkType.not_required,
requiresBatteryNotLow: false,
requiresCharging: false,
requiresDeviceIdle: false,
requiresStorageNotLow: false));
runApp(MyApp());
class MyApp extends StatelessWidget
// This widget is the root of your application.
@override
Widget build(BuildContext context)
return MaterialApp(
title: 'GetPrayer',
theme: ThemeData(
brightness: Brightness.dark,
primarySwatch: Colors.cyan,
),
home: GetPrayersPage(),
);
class GetPrayersPage extends StatefulWidget
@override
_GetPrayersPageState createState() => _GetPrayersPageState();
class _GetPrayersPageState extends State<GetPrayersPage>
tz.TZDateTime fajr;
tz.TZDateTime dhuhr;
tz.TZDateTime maghrib;
tz.TZDateTime asr;
tz.TZDateTime isha;
@override
void initState()
super.initState();
loalData();
void loalData() async
fajr = await PrayerTime.instance.getFajr();
dhuhr = await PrayerTime.instance.getdhuhr();
maghrib = await PrayerTime.instance.getmaghrib();
asr = await PrayerTime.instance.getasr();
isha = await PrayerTime.instance.getisha();
setState(() );
@override
Widget build(BuildContext context)
return Scaffold(
appBar: AppBar(
title: Text('Prayer times'),
elevation: 0.0,
),
body: Column(
mainAxisSize: MainAxisSize.min,
children: [
ListTile(
leading: Icon(Icons.calendar_today),
title: Text("Fajr"),
trailing: Text("$fajr.toString()"),
),
ListTile(
leading: Icon(Icons.calendar_today),
title: Text("Dhuhr"),
trailing: Text("$dhuhr.toString()"),
),
ListTile(
leading: Icon(Icons.calendar_today),
title: Text("Maghrib"),
trailing: Text("$maghrib.toString()"),
),
ListTile(
leading: Icon(Icons.calendar_today),
title: Text("Asr"),
trailing: Text("$asr.toString()"),
),
ListTile(
leading: Icon(Icons.calendar_today),
title: Text("Isha"),
trailing: Text("$isha.toString()"),
),
],
),
bottomNavigationBar: Container(
child: ElevatedButton(
style: ButtonStyle(
minimumSize:
MaterialStateProperty.all(Size(double.infinity, 60))),
onPressed: ()
PrayerTime.instance.getPrayers();
,
child: Text("UPDATE"),
),
),
);
void callbackDispatcher()
Workmanager.executeTask((task, inputData) async
switch (task)
case taskName:
PrayerTime.instance.getPrayers();
await NotificationManager().initNotificationManager();
await NotificationManager().zonedNotification();
await NotificationManager().showNotification();
break;
return Future.value(true);
);
print(taskName + "callbackDispatcher");
prayer_times.dart
import 'package:adhan/adhan.dart';
import 'package:notify/local_notification/get_timezone_date.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:timezone/timezone.dart' as tz;
class PrayerTime
static const String fajrKey = "fajr";
static const String sunriseKey = "sunrise";
static const String dhuhrKey = "dhuhr";
static const String asrKey = "asr";
static const String maghribKey = "maghrib";
static const String ishaKey = "maghrib";
PrayerTime._privateConstructor();
static final PrayerTime _instance = PrayerTime._privateConstructor();
static PrayerTime get instance => _instance;
List<String> prayerTimesList = [];
void getPrayers() async
final myCoordinates = Coordinates(19.076090, 72.877426);
final params = CalculationMethod.karachi.getParameters();
params.madhab = Madhab.hanafi;
final prayerTimes = PrayerTimes.today(myCoordinates, params);
final datewa = DateTime.now().add(Duration(minutes: 5));
String _formatTime(DateTime time)
return time.toIso8601String();
savePrayers(
fajr: _formatTime(datewa),
// fajr: _formatTime(prayerTimes.fajr),
dhuhr: _formatTime(prayerTimes.dhuhr),
asr: _formatTime(prayerTimes.asr),
maghrib: _formatTime(prayerTimes.maghrib),
isha: _formatTime(prayerTimes.isha),
);
void savePrayers(
String fajr,
String dhuhr,
String asr,
String maghrib,
String isha,
) async
SharedPreferences prefs = await SharedPreferences.getInstance();
await prefs.setString(fajrKey, fajr);
await prefs.setString(dhuhrKey, dhuhr);
await prefs.setString(asrKey, asr);
await prefs.setString(maghribKey, maghrib);
await prefs.setString(ishaKey, isha);
Future<tz.TZDateTime> getFajr() async
SharedPreferences prefs = await SharedPreferences.getInstance();
return convertToTZ(DateTime.parse(prefs.getString(fajrKey)));
Future<tz.TZDateTime> getdhuhr() async
SharedPreferences prefs = await SharedPreferences.getInstance();
return convertToTZ(DateTime.parse(prefs.getString(dhuhrKey)));
Future<tz.TZDateTime> getasr() async
SharedPreferences prefs = await SharedPreferences.getInstance();
return convertToTZ(DateTime.parse(prefs.getString(asrKey)));
Future<tz.TZDateTime> getmaghrib() async
SharedPreferences prefs = await SharedPreferences.getInstance();
return convertToTZ(DateTime.parse(prefs.getString(maghribKey)));
Future<tz.TZDateTime> getisha() async
SharedPreferences prefs = await SharedPreferences.getInstance();
return convertToTZ(DateTime.parse(prefs.getString(ishaKey)));
manage_notification.dart
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:notify/prayer_times.dart';
import 'package:timezone/timezone.dart' as tz;
class NotificationManager
FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin;
AndroidInitializationSettings initializationSettingsAndroid;
iosInitializationSettings initializationSettingsIOS;
InitializationSettings initializationSettings;
/// Initializing FlutterLocalNotificationsPlugin.
Future initNotificationManager() async
flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();
initializationSettingsAndroid =
AndroidInitializationSettings('ic_launcher');
initializationSettingsIOS = IOSInitializationSettings();
initializationSettings = InitializationSettings(
android: initializationSettingsAndroid, iOS: initializationSettingsIOS);
await flutterLocalNotificationsPlugin.initialize(initializationSettings);
Future<void> zonedNotification() async
/// List of prayer times.
List<tz.TZDateTime> _times = [
await PrayerTime.instance.getFajr(),
await PrayerTime.instance.getdhuhr(),
await PrayerTime.instance.getmaghrib(),
await PrayerTime.instance.getasr(),
await PrayerTime.instance.getisha(),
];
/// Vibration pattern.
var vibrationPattern = Int64List(4);
vibrationPattern[0] = 0;
vibrationPattern[1] = 1000;
vibrationPattern[2] = 5000;
vibrationPattern[3] = 2000;
/// Android Specifics.
var androidPlatformChannelSpecifics = AndroidNotificationDetails(
"0", "channel Name", "channel Description",
icon: 'ic_launcher',
sound: RawResourceAndroidNotificationSound("slow_spring_board"),
largeIcon: DrawableResourceAndroidBitmap('ic_launcher'),
vibrationPattern: vibrationPattern,
autoCancel: false,
enableLights: true,
playSound: true,
color: Colors.green,
ledColor: const Color.fromARGB(255, 255, 0, 0),
ledOnMs: 1000,
ledOffMs: 500);
/// iOS Specifics.
IOSNotificationDetails iOSPlatformChannelSpecifics =
IOSNotificationDetails(sound: 'slow_spring_board.aiff');
/// Platform channel specifics.
NotificationDetails platformChannelSpecifics = NotificationDetails(
android: androidPlatformChannelSpecifics,
iOS: iOSPlatformChannelSpecifics);
/// ZonedSchedule
_times.forEach((element) async
await flutterLocalNotificationsPlugin.zonedSchedule(
0, "Title", "Body", element, platformChannelSpecifics,
uiLocalNotificationDateInterpretation:
UILocalNotificationDateInterpretation.absoluteTime,
androidAllowWhileIdle: true);
);
Future<void> showNotification() async
var androidPlatformChannelSpecifics = AndroidNotificationDetails(
"1", 'channel name', 'channel description',
importance: Importance.high, priority: Priority.high, ticker: 'ticker');
var iOSPlatformChannelSpecifics = IOSNotificationDetails();
var platformChannelSpecifics = NotificationDetails(
android: androidPlatformChannelSpecifics,
iOS: iOSPlatformChannelSpecifics);
await flutterLocalNotificationsPlugin.show(
0, 'plain title', 'plain body', platformChannelSpecifics,
payload: 'item x');
get_timezone.dart
import 'package:timezone/data/latest.dart';
import 'package:timezone/timezone.dart' as tz;
import 'package:flutter_native_timezone/flutter_native_timezone.dart';
class TimeZone
factory TimeZone() => _this ?? TimeZone._();
TimeZone._()
initializeTimeZones();
static TimeZone _this;
Future<String> getTimeZoneName() async =>
FlutterNativeTimezone.getLocalTimezone();
Future<tz.Location> getLocation([String timeZoneName]) async
if (timeZoneName == null || timeZoneName.isEmpty)
timeZoneName = await getTimeZoneName();
return tz.getLocation(timeZoneName);
Future<tz.TZDateTime> convertToTZ(dateTime) async
final timeZone = TimeZone();
String timeZoneName = await timeZone.getTimeZoneName();
final location = await timeZone.getLocation(timeZoneName);
final scheduledDate = tz.TZDateTime.from(dateTime, location);
print(scheduledDate.toString());
return scheduledDate;
扑医生
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 2.0.1, on Linux, locale en_US.UTF-8)
[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
[✓] Chrome - develop for the web
[!] Android Studio (not installed)
[✓] VS Code (version 1.54.3)
[✓] Connected device (2 available)
! Doctor found issues in 1 category.
pubspec.yaml*
version: 1.0.0+1
environment:
sdk: ">=2.7.0 <3.0.0"
dependencies:
flutter:
sdk: flutter
workmanager: ^0.2.3
shared_preferences: ^2.0.5
adhan: ^1.1.15
intl: ^0.17.0
background_location: ^0.4.1
flutter_local_notifications: 4.0.1+2
flutter_native_timezone: ^1.0.10
# The following adds the Cupertino Icons font to your application.
# Use the CupertinoIcons class for iOS style icons.
cupertino_icons: ^1.0.2
dev_dependencies:
flutter_test:
sdk: flutter
【问题讨论】：
【参考方案1】：在 try/catch 中调用您的代码并查看错误并将您的实例设置为变量：
try
PrayerTime.instance.getPrayers();
NotificationManager manager = new NotificationManager();
await manager.initNotificationManager();
await manager.zonedNotification();
await manager.showNotification();
catch(e)
print(e);
【讨论】：
【参考方案2】：遇到同样的错误，手动清除缓存或者flutter clean，然后删除手机中的应用...然后通过android studio重新安装应用，这样，我的问题就解决了
【讨论】：
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