Cloud Messaging (push notifications) in Android Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Firebase Cloud Messaging (FCM)?

Firebase Cloud Messaging (FCM) is a free service by Google that lets you send notifications and messages to Android, iOS, and web apps. It helps apps stay connected with users by delivering push notifications.

beginner

Which Android component handles incoming push notifications?

The FirebaseMessagingService class handles incoming push notifications. You create a subclass and override the onMessageReceived() method to define how your app reacts when a message arrives.

intermediate

What is the purpose of a notification channel in Android push notifications?

Notification channels group notifications by type and let users control settings like sound and vibration for each channel. They are required for Android 8.0 (API level 26) and above.

intermediate

How do you get the device token for FCM in Kotlin?

You get the device token by calling FirebaseMessaging.getInstance().token.addOnCompleteListener { ... } which asynchronously returns the unique token identifying the device for push messages.

beginner

Why is it important to handle notification clicks in your app?

Handling notification clicks lets you control what happens when a user taps a notification, such as opening a specific screen. This improves user experience by linking notifications to relevant app content.

Which class should you extend to handle incoming FCM messages in Android?

A FirebaseMessagingService

B FirebaseInstanceIdService

C NotificationManager

D FirebaseAuth

FirebaseMessagingService is the class designed to receive and handle incoming FCM messages.

What Android version introduced notification channels?

A Android 7.0 Nougat

B Android 9.0 Pie

C Android 8.0 Oreo

D Android 6.0 Marshmallow

Notification channels were introduced in Android 8.0 Oreo to organize notifications and allow user control.

How do you obtain the FCM device token in Kotlin?

A FirebaseInstanceId.getToken()

B FirebaseMessaging.getInstance().token.addOnCompleteListener { ... }

C NotificationManager.getToken()

D FirebaseAuth.getInstance().currentUser

The recommended way is to call FirebaseMessaging.getInstance().token asynchronously to get the device token.

What is the main purpose of a notification channel?

A To store notification data

B To send messages to multiple devices

C To authenticate users

D To group notifications and let users control their settings

Notification channels group notifications and allow users to customize settings like sound and vibration.

Which Firebase service is used to send push notifications?

A Firebase Cloud Messaging

B Firebase Realtime Database

C Firebase Authentication

D Firebase Storage

Firebase Cloud Messaging is the service used to send push notifications to apps.

Explain how to set up Firebase Cloud Messaging in an Android app using Kotlin.

Think about the steps from adding Firebase to handling messages and notifications.

Describe why notification channels are important and how they affect user experience.

Consider how users interact with notifications and their settings.