使用 Android 代码和 FCM 的 Flutter MissingPluginException

Question

当我收到 Firebase 消息 (FCM) 时，我想在 Android 中启动一些本机代码，但收到此错误：

E/flutter (16352): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: MissingPluginException(No implementation found for method wakeUpApp on channel com.diesetelecom.smartdiese.androidChannel)
E/flutter (16352): #0      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:332:7)
E/flutter (16352): <asynchronous suspension>

我已经尝试卸载应用程序 -> flutter clean -> flutter pub get -> flutter run 但没有成功

这是我的 main.dart 中 flutter 中的代码，我尝试删除“com.diesetelecom.smartdiese”以保留“androidChannel”，但我仍然遇到错误。

@pragma('vm:entry-point')
Future<void> firebaseMessagingBackgroundHandler(RemoteMessage message) async {
  ...
  const MethodChannel androidChannel = MethodChannel('com.diesetelecom.smartdiese.androidChannel');
  androidChannel.invokeMethod("wakeUpApp");
}

Future<void> main() async { 
    ...

    FirebaseMessaging.onBackgroundMessage(firebaseMessagingBackgroundHandler);

    ...

  await AssetsManager.initAssets();

  await dotenv.load();

  runApp(const App());
}

这是我的 MainActivity.kt，知道当我尝试从 firebaseMessagingBackgroundHandler 调用 Android 方法时出现此错误，但它在外部工作

package com.diesetelecom.smart_diese

import android.content.Context
import android.content.Intent
import android.media.AudioManager
import androidx.annotation.NonNull
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodCall
import io.flutter.plugin.common.MethodChannel
import android.util.Log

class MainActivity: FlutterActivity() {
    private val CHANNEL = "androidChannel"

    override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)
        MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL).setMethodCallHandler { call, result ->
            if (call.method == "switchAudioOutput") {
                val audioManager: AudioManager = getApplicationContext().getSystemService(Context.AUDIO_SERVICE) as AudioManager
                audioManager.setMode(AudioManager.MODE_IN_CALL)
                audioManager.setSpeakerphoneOn(!audioManager.isSpeakerphoneOn)
                result.success(audioManager.isSpeakerphoneOn)
            } else if(call.method == "wakeUpApp") {
                Log.d("ActivityMain", "This is a small test text")
                result.success(true)
            } else {
                result.notImplemented()
            }
        }
    }
}

Answer 1

我注意到您的

MainActivity.kt

文件中存在问题。您已经创建了一个名为

CHANNEL

的顶级变量

private val CHANNEL = "androidChannel"

。

请记住，您的方法通道名称应在两个平台中同步，即在

Flutter

和

Kotlin

或

Swift

中。您尝试从

wakeUpApp

平台调用

Flutter

方法，方法通道名称为

com.diesetelecom.smartdiese.androidChannel

，而在

Kotlin

中，没有具有此名称的方法通道，因为您在 android 中将通道名称设置为

androidChannel

这就是为什么没有针对您在

Flutter

代码中指定的名称的实现。

您应该尝试以下代码才能使其运行：

颤动面：

@pragma('vm:entry-point')
Future<void> firebaseMessagingBackgroundHandler(RemoteMessage message) async {
  ...
  const MethodChannel androidChannel = MethodChannel('com.diesetelecom.smartdiese.androidChannel');
  androidChannel.invokeMethod("wakeUpApp");
}

Future<void> main() async { 
    ...

    FirebaseMessaging.onBackgroundMessage(firebaseMessagingBackgroundHandler);

    ...

  await AssetsManager.initAssets();

  await dotenv.load();

  runApp(const App());
}

Kotlin 方面：

package com.diesetelecom.smart_diese

import android.content.Context
import android.content.Intent
import android.media.AudioManager
import androidx.annotation.NonNull
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodCall
import io.flutter.plugin.common.MethodChannel
import android.util.Log

class MainActivity: FlutterActivity() {
    private val CHANNEL = "com.diesetelecom.smartdiese.androidChannel"

    override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)
        MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL).setMethodCallHandler { call, result ->
            if (call.method == "switchAudioOutput") {
                val audioManager: AudioManager = getApplicationContext().getSystemService(Context.AUDIO_SERVICE) as AudioManager
                audioManager.setMode(AudioManager.MODE_IN_CALL)
                audioManager.setSpeakerphoneOn(!audioManager.isSpeakerphoneOn)
                result.success(audioManager.isSpeakerphoneOn)
            } else if(call.method == "wakeUpApp") {
                Log.d("ActivityMain", "This is a small test text")
                result.success(true)
            } else {
                result.notImplemented()
            }
        }
    }
}