本地通知处理方法调用失败

Question

我正在测试这个 this 插件以获取本地通知。我想在按下按钮时显示通知，这是我的代码：

FlatButton(
            onPressed: () {
              FlutterLocalNotificationsPlugin localNotifPlugin =
                  new FlutterLocalNotificationsPlugin();
              var androidChannelSpecifics = AndroidNotificationDetails(
                  'default',
                  'Test App Notifications',
                  'Channel for default notifications from test app');
              var iOSChannelSpecifics = IOSNotificationDetails();
              var platformChannelSpecifics = NotificationDetails(
                  androidChannelSpecifics, iOSChannelSpecifics);
              localNotifPlugin.show(
                  0,
                  "Test Notificaiton",
                  "This is your test notification! :)",
                  platformChannelSpecifics);
            },
            child: Text("Show Notification"),
          )

这与插件的文档非常相似，但它不起作用，当我按下按钮时出现此错误：

    D/EGL_emulation(24401): eglMakeCurrent: 0xa80053c0: ver 2 0 (tinfo 0xa8003360)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401): Failed to handle method call
E/MethodChannel#dexterous.com/flutter/local_notifications(24401): 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(24401):   at com.dexterous.flutterlocalnotifications.FlutterLocalNotificationsPlugin.setSmallIcon(FlutterLocalNotificationsPlugin.java:156)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at com.dexterous.flutterlocalnotifications.FlutterLocalNotificationsPlugin.createNotification(FlutterLocalNotificationsPlugin.java:131)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at com.dexterous.flutterlocalnotifications.FlutterLocalNotificationsPlugin.showNotification(FlutterLocalNotificationsPlugin.java:598)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at com.dexterous.flutterlocalnotifications.FlutterLocalNotificationsPlugin.show(FlutterLocalNotificationsPlugin.java:690)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at com.dexterous.flutterlocalnotifications.FlutterLocalNotificationsPlugin.onMethodCall(FlutterLocalNotificationsPlugin.java:619)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:222)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at io.flutter.embedding.engine.dart.DartMessenger.handleMessageFromDart(DartMessenger.java:96)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(FlutterJNI.java:656)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at android.os.MessageQueue.nativePollOnce(Native Method)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at android.os.MessageQueue.next(MessageQueue.java:323)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at android.os.Looper.loop(Looper.java:136)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at android.app.ActivityThread.main(ActivityThread.java:6077)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at java.lang.reflect.Method.invoke(Native Method)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
E/MethodChannel#dexterous.com/flutter/local_notifications(24401):   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
E/flutter (24401): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: PlatformException(error, Attempt to invoke virtual method 'int java.lang.Integer.intValue()' on a null object reference, null)
E/flutter (24401): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:569:7)
E/flutter (24401): #1      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:316:33)
E/flutter (24401): <asynchronous suspension>
E/flutter (24401): #2      FlutterLocalNotificationsPlugin.show (package:flutter_local_notifications/src/flutter_local_notifications.dart:120:20)
E/flutter (24401): <asynchronous suspension>
E/flutter (24401): #3      HomePage.build.<anonymous closure> (package:provider_test/main.dart:53:36)
E/flutter (24401): #4      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:654:14)
E/flutter (24401): #5      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:729:32)
E/flutter (24401): #6      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter (24401): #7      TapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:365:11)
E/flutter (24401): #8      TapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:275:7)
E/flutter (24401): #9      PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:455:9)
E/flutter (24401): #10     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:75:13)
E/flutter (24401): #11     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:102:11)
E/flutter (24401): #12     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:218:19)
E/flutter (24401): #13     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
E/flutter (24401): #14     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
E/flutter (24401): #15     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
E/flutter (24401): #16     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
E/flutter (24401): #17     _rootRunUnary (dart:async/zone.dart:1136:13)
E/flutter (24401): #18     _CustomZone.runUnary (dart:async/zone.dart:1029:19)
E/flutter (24401): #19     _CustomZone.runUnaryGuarded (dart:async/zone.dart:931:7)
E/flutter (24401): #20     _invoke1 (dart:ui/hooks.dart:263:10)
E/flutter (24401): #21     _dispatchPointerDataPacket (dart:ui/hooks.dart:172:5)

我做错了什么？

Answer 1

看起来您在初始化插件时没有或使用了错误的 app_icon；

在您的 initState 中，您应该使用正确的图标名称进行初始化：

@override
 void initState() {
   super.initState();
   FlutterLocalNotificationsPlugin flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();
   var initializationSettingsAndroid = AndroidInitializationSettings('app_icon'); // <- default icon name is @mipmap/ic_launcher
   var initializationSettingsIOS = IOSInitializationSettings(onDidReceiveLocalNotification: onDidReceiveLocalNotification);
   var initializationSettings = InitializationSettings(initializationSettingsAndroid, initializationSettingsIOS);
   flutterLocalNotificationsPlugin.initialize(initializationSettings, onSelectNotification: onSelectNotification); }

https://github.com/MaikuB/flutter_local_notifications#getting-started

How to change the application launcher icon on Flutter?

Answer 2

我通过在初始化android设置时指示文件类型来解决问题如下：

var initializationSettingsAndroid = AndroidInitializationSettings('app_icon.png');

或者，您可以像这样将图标设置为默认值：

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

希望这会有所帮助。

Answer 3

对于flutter local notifications，首先您必须在android res/drawable 文件夹中添加图标。然后你应该在 AndroidInitializationSettings 类中提交这个图标名称，否则你会得到错误。

@override
void initState() {
super.initState();
var androidSettings = AndroidInitializationSettings(‘app_icon’);
var iOSSettings = IOSInitializationSettings(
    requestSoundPermission: false,
    requestBadgePermission: false,
    requestAlertPermission: false,
);
var initSetttings = InitializationSettings(androidSettings, iOSSettings);
flutterLocalNotificationsPlugin.initialize(initSetttings, onSelectNotification: onClickNotification);
}