flutter - Flutter本地通知引发错误

Question

尝试显示flutter_local_notification的通知时，它将引发以下错误:

E/MethodChannel#dexterous.com/flutter/local_notifications(10962): Failed to handle method call
E/MethodChannel#dexterous.com/flutter/local_notifications(10962): java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.Integer.intValue()' on a null object reference
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at com.dexterous.flutterlocalnotifications.FlutterLocalNotificationsPlugin.setSmallIcon(FlutterLocalNotificationsPlugin.java:188)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at com.dexterous.flutterlocalnotifications.FlutterLocalNotificationsPlugin.createNotification(FlutterLocalNotificationsPlugin.java:146)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at com.dexterous.flutterlocalnotifications.FlutterLocalNotificationsPlugin.showNotification(FlutterLocalNotificationsPlugin.java:688)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at com.dexterous.flutterlocalnotifications.FlutterLocalNotificationsPlugin.show(FlutterLocalNotificationsPlugin.java:827)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at com.dexterous.flutterlocalnotifications.FlutterLocalNotificationsPlugin.onMethodCall(FlutterLocalNotificationsPlugin.java:750)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:226)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at io.flutter.embedding.engine.dart.DartMessenger.handleMessageFromDart(DartMessenger.java:85)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(FlutterJNI.java:631)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at android.os.MessageQueue.nativePollOnce(Native Method)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at android.os.MessageQueue.next(MessageQueue.java:325)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at android.os.Looper.loop(Looper.java:142)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at android.app.ActivityThread.main(ActivityThread.java:6494)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at java.lang.reflect.Method.invoke(Native Method)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
E/MethodChannel#dexterous.com/flutter/local_notifications(10962):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
E/flutter (10962): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: PlatformException(error, Attempt to invoke virtual method 'int java.lang.Integer.intValue()' on a null object reference, null)
E/flutter (10962): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:569:7)
E/flutter (10962): #1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:156:18)
E/flutter (10962): <asynchronous suspension>
E/flutter (10962): #2      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:329:12)
E/flutter (10962): #3      AndroidFlutterLocalNotificationsPlugin.show (package:flutter_local_notifications/src/platform_flutter_local_notifications.dart:137:21)
E/flutter (10962): #4      FlutterLocalNotificationsPlugin.show (package:flutter_local_notifications/src/flutter_local_notifications_plugin.dart:136:13)
E/flutter (10962): #5      NotificationPlugin.showNotification (package:pig_salang/models/notification_plugin.dart:94:43)
E/flutter (10962): #6      WelcomeScreen.build.<anonymous closure> (package:pig_salang/screens/welcome_screen.dart:42:36)
E/flutter (10962): #7      WelcomeScreen.build.<anonymous closure> (package:pig_salang/screens/welcome_screen.dart:41:26)
E/flutter (10962): #8      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:779:19)
E/flutter (10962): #9      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:862:36)
E/flutter (10962): #10     GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter (10962): #11     TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:504:11)
E/flutter (10962): #12     BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:282:5)
E/flutter (10962): #13     BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:217:7)
E/flutter (10962): #14     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:475:9)
E/flutter (10962): #15     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:76:12)
E/flutter (10962): #16     PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:122:9)
E/flutter (10962): #17     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:379:8)
E/flutter (10962): #18     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:120:18)
E/flutter (10962): #19     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:106:7)
E/flutter (10962): #20     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:218:19)
E/flutter (10962): #21     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
E/flutter (10962): #22     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
E/flutter (10962): #23     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
E/flutter (10962): #24     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
E/flutter (10962): #25     _rootRunUnary (dart:async/zone.dart:1196:13)
E/flutter (10962): #26     _CustomZone.runUnary (dart:async/zone.dart:1085:19)
E/flutter (10962): #27     _CustomZone.runUnaryGuarded (dart:async/zone.dart:987:7)
E/flutter (10962): #28     _invoke1 (dart:ui/hooks.dart:275:10)
E/flutter (10962): #29     _dispatchPointerDataPacket (dart:ui/hooks.dart:184:5)
E/flutter (10962): 

据我研究，由于 图标而显示了类似的错误。我已经添加了使用所有可能的方式添加图标的方法，但是它并没有不断抛出错误。显然，每次更改后我都会重新运行该应用程序，以确保不会出现错误。
我的代码如下:

initializePlatformSpecifics() {
    var initializeAndroidSettings = AndroidInitializationSettings('app_icon'); <--- Here
    var initializeIOSSettings = IOSInitializationSettings(
      requestAlertPermission: false,
      requestBadgePermission: true,
      requestSoundPermission: true,
      onDidReceiveLocalNotification: (id, title, body, payload) async {
        ReceivedNotification receivedNotification = ReceivedNotification(
            id: id, title: title, body: body, payload: payload);
        didReceivedLocalNotificationSubject.add(receivedNotification);
      },
    );

    initializeSettings = InitializationSettings(
        initializeAndroidSettings, initializeIOSSettings);
  }

我遵循了 tutorial。问题是当我尝试显示通知时，它显示了上面的回溯。

我在Android Studio->应用程序->主菜单-> res->图像 Assets ->通知图标中创建了通知图标，然后我使用名称 app_icon创建了用于初始化通知的图标。
由于它不起作用，我还尝试了:

var initializeAndroidSettings = AndroidInitializationSettings('@mipmap/ic_launcher');

它也没有用。任何帮助，将不胜感激!!!

Answer 1

给出了“app_icon”作为引用，它实际上取决于图像文件所在的位置，如果您现在正在使用名为ic_launcher的mipmap文件夹中的默认图标，请尝试以下代码。让我知道是否有帮助。

var initializeAndroidSettings 
=AndroidInitializationSettings('mipmap/ic_launcher');