firebase_messaging version 7.0.3 (current) and lower do not allow to set up a notification channel, thus notifications don't play any sounds or do not display on locked screen, or don't bubble and so on. This plugin is made merely for the purpose of creation a notification channel with difference configuration on Android. The channel then can be used along with firebase_messaging.
I'm looking for an easy way to configure a new Notification Channel with a custom sound file (e.g. *.wav file).
I think it would be valuable to support a method for specifying a "customSound" property (in addition to "enableSound"). The customSound would be String representing the name of a file to be used instead of the system notification sound (Settings.System.DEFAULT_NOTIFICATION_URI). The "customSound" would be passed as a string and be resolved through the application res/raw resources. Maybe something like:
uri = Uri.parse(ContentResolver.SCHEME_ANDROID_RESOURCE + "://"+ getApplicationContext().getPackageName() + "/raw/");