Firebase 消息回调之间的区别

Question

I'm having a hard time finding any site that clearly explains the differences between the firebase messaging callbacks of onBackgroundMessage, onLaunch, and onResume. These words may seem common sense but they are not. I need a clear explanation of the differences between these callbacks. In what situations are these callbacks used?

Answer 1

As far as I know, Firebase Cloud Messaging is not only used for sending Notifications.
With FCM, you can send two types of messages to clients:
Notification messages sometimes thought of as "display messages." These are handled by the FCM SDK automatically.
Data messages , which are handled by the client app.

This Official Documentation explains it all.
Functions Reference: https://pub.dev/packages/firebase_messaging#receiving-messages
Message Types Reference: https://firebase.google.com/docs/cloud-messaging/concept-options#notifications_and_data_messages