activity.kt

val notificationListenerString = Settings.Secure.getString(this.contentResolver, "enabled_notification_listeners")
if (!(notificationListenerString != null && notificationListenerString.contains(packageName))) {
  val requestIntent = Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS")
  requestIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
  context.startActivity(requestIntent)
}

manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="br.com.firstsoft.historiconotificacoes.notificationrecorder">

    <application>
        <service
            android:name="br.com.firstsoft.historiconotificacoes.notificationrecorder.src.service.NotificationRecorderService"
            android:exported="true"
            android:label="Notification Recorder Service"
            android:permission="android.permission.BIND_NOTIFICATION_LISTENER_SERVICE">
            <intent-filter>
                <action android:name="android.service.notification.NotificationListenerService" />
            </intent-filter>
        </service>
    </application>
</manifest>

NotificationRecorderService.kt

package br.com.firstsoft.historiconotificacoes.notificationrecorder.src.service

import android.app.Notification.EXTRA_BIG_TEXT
import android.app.Notification.EXTRA_TEXT
import android.app.Notification.EXTRA_TITLE
import android.content.pm.ApplicationInfo
import android.os.Bundle
import android.service.notification.NotificationListenerService
import android.service.notification.StatusBarNotification
import br.com.firstsoft.historiconotificacoes.domain.src.model.AppNotification
import br.com.firstsoft.historiconotificacoes.domain.src.usecase.notification.SaveNotificationUseCase
import dagger.hilt.android.AndroidEntryPoint
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import javax.inject.Inject

@AndroidEntryPoint
class NotificationRecorderService : NotificationListenerService() {

    @Inject
    lateinit var saveNotificationUseCase: SaveNotificationUseCase

    override fun onNotificationPosted(sbn: StatusBarNotification) {
        super.onNotificationPosted(sbn)

        val notification = AppNotification(
            id = sbn.id,
            appName = getApplicationName(sbn.packageName),
            title = sbn.notification.extras.get(EXTRA_TITLE)?.toString() ?: "",
            message = getNotificationText(sbn.notification.extras),
            packageName = sbn.packageName,
            createdTime = sbn.postTime,
            extras = getAvailableKeysAndValues(sbn.notification.extras, sbn.packageName)
        )

        CoroutineScope(Dispatchers.IO).launch {
            saveNotificationUseCase(SaveNotificationUseCase.Input(notification))
        }
    }

    private fun getAvailableKeysAndValues(
        extras: Bundle?,
        packageName: String
    ): Map<String, String> {
        if (extras == null) {
            return emptyMap()
        }

        val map = mutableMapOf<String, String>()
        extras.keySet().forEach { key ->
            val value = extras[key]

            if (value != null) {
                when (value.javaClass) {
                    java.lang.String::class,
                    java.lang.Boolean::class,
                    java.lang.Integer::class -> {
                        map[key] = value.toString()
                    }
                }
            }
        }

        return map
    }

    private fun getApplicationName(packageName: String): String {
        val ai: ApplicationInfo? = try {
            packageManager.getApplicationInfo(packageName, 0)
        } catch (e: Exception) {
            null
        }

        return (if (ai != null) packageManager.getApplicationLabel(ai) else "(unknown)") as String
    }

    private fun getNotificationText(bundle: Bundle): String {
        val title = (bundle.get(EXTRA_TEXT) ?: bundle.get(EXTRA_BIG_TEXT)) ?: ""
        return title.toString()
    }
}