Flutter Custom Notification Application.kt: Unresolved reference

Question

Im new to flutter, I want to have custom ringtone notifications, flutter version is 2.8, I found some tutorials talk about creating application.kt in kotlin folder same where locate mainactivity file, save wave file in the resource folder for android and in runner for ios, all I found just to have the below code in Application file and modify the AndroidMainifest file, this was working with me, but I need to update flutter from old version to the current one, after I update it, the app stop working because of the Application file returns the error below, what can I do to let this works again, sorry for my basic language, hopefully you have a clear solution for this issue ,thank you

Error

 /android/app/src/main/kotlin/com/foodeasy/merchant/Application.kt: (7, 31): Unresolved reference: firebasemessaging
  e: /app/src/main/kotlin/com/foodeasy/merchant/Application.kt: (19, 5): Class 'Application' is not abstract and does not implement abstract member public abstract fun registerWith(p0: PluginRegistry!): Unit defined in io.flutter.plugin.common.PluginRegistry.PluginRegistrantCallback

AndroidMainifest

  <application
    android:name=".Application"
    android:label="myapp"
    android:requestLegacyExternalStorage="true"
    android:usesCleartextTraffic="true"
    android:icon="@mipmap/ic_launcher">


package com.*****.****

import io.flutter.app.FlutterApplication
import io.flutter.plugin.common.PluginRegistry
import io.flutter.plugins.GeneratedPluginRegistrant
import io.flutter.plugin.common.PluginRegistry.PluginRegistrantCallback
import io.flutter.plugins.firebasemessaging.FlutterFirebaseMessagingService

import android.app.NotificationChannel
import android.app.NotificationManager
import android.content.Context
import android.media.AudioAttributes
import android.net.Uri
import android.os.Build
import android.util.Log



class Application : FlutterApplication(), PluginRegistrantCallback {
    private fun createChannel(){

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val sound = Uri.parse("android.resource://" + applicationContext.packageName + "/raw/" + R.raw.ntf)
            // Create the NotificationChannel
            val channel = NotificationChannel("mychannel", "default", NotificationManager.IMPORTANCE_HIGH)
            val audioAttributes = AudioAttributes.Builder()
                    .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
                    .setUsage(AudioAttributes.USAGE_ALARM)
                    .build()
            channel.setSound(sound, audioAttributes)
            val notificationManager: NotificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
            notificationManager.createNotificationChannel(channel)
        }
    }

    override fun onCreate() {
        super.onCreate()
    }

}

Answer 1

you can get getSystemService from context change your code

from:

val notificationManager: NotificationManager = getSystemService(context.NOTIFICATION_SERVICE) as NotificationManager

to:

val notificationManager: NotificationManager = context.getSystemService(context.NOTIFICATION_SERVICE) as NotificationManager

where context is context = flutterPluginBinding.getApplicationContext();