Allow custom notification channel

Author: F43nd1r

acra-notification/src/main/java/org/acra/config/NotificationConfiguration.kt

@@ -19,6 +19,7 @@ package org.acra.config
 import androidx.annotation.ColorInt
 import androidx.annotation.DrawableRes
 import com.faendir.kotlin.autodsl.AutoDsl
+import com.faendir.kotlin.autodsl.AutoDslRequired
 import org.acra.annotation.AcraDsl
 import org.acra.ktx.plus
 
@@ -103,14 +104,27 @@ class NotificationConfiguration(
     @DrawableRes
     val resDiscardButtonIcon: Int = android.R.drawable.ic_menu_delete,
 
+    /**
+     * Existing notification channel id.
+     * You have to ensure a notification channel with this id exists (See [android.app.NotificationManager.createNotificationChannel]).
+     * If null, ACRA will create a notification channel for you with the provided [channelName], [channelDescription] and [channelImportance].
+     * To learn about notification channels, visit the [notification guide](https://developer.android.com/guide/topics/ui/notifiers/notifications.html#ManageChannels)
+     *
+     * @see android.app.NotificationChannel
+     * @since 5.12.0
+     */
+    @AutoDslRequired("channel")
+    val channelId: String? = null,
+
     /**
      * notification channel name.
      * To learn about notification channels, visit the [notification guide](https://developer.android.com/guide/topics/ui/notifiers/notifications.html#ManageChannels)
      *
      * @see android.app.NotificationChannel
      * @since 5.0.0
      */
-    val channelName: String,
+    @AutoDslRequired("channel")
+    val channelName: String? = null,
 
     /**
      * notification channel description

acra-notification/src/main/java/org/acra/interaction/NotificationInteraction.kt

@@ -54,7 +54,7 @@ class NotificationInteraction : HasConfigPlugin(NotificationConfiguration::class
         //can't post notifications
         val notificationConfig = config.getPluginConfiguration<NotificationConfiguration>()
         //We have to create a channel on Oreo+, because notifications without one aren't allowed
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && notificationConfig.channelId == null) {
             @SuppressLint("WrongConstant")
             val channel = NotificationChannel(CHANNEL, notificationConfig.channelName, notificationConfig.channelImportance)
             channel.setSound(null, null)
@@ -64,7 +64,7 @@ class NotificationInteraction : HasConfigPlugin(NotificationConfiguration::class
             notificationManager.createNotificationChannel(channel)
         }
         //configure base notification
-        val notification = NotificationCompat.Builder(context, CHANNEL)
+        val notification = NotificationCompat.Builder(context, notificationConfig.channelId ?: CHANNEL)
             .setWhen(System.currentTimeMillis())
             .setContentTitle(notificationConfig.title)
             .setContentText(notificationConfig.text)