Cloud Messaging (push notifications) in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize Firebase Cloud Messaging in an Android app.

Android Kotlin

FirebaseMessaging.getInstance().[1]()

Drag options to blanks, or click blank then click option'

AsubscribeToTopic

BdeleteToken

CsendMessage

DgetToken

Attempts:

3 left

💡 Hint

Common Mistakes

Using subscribeToTopic instead of getToken

Trying to send a message from the client side

Calling deleteToken which removes the token

The getToken() method retrieves the current registration token for the device, which is needed to receive push notifications.

2fill in blank

medium

Complete the code to subscribe the device to a topic named "news" for receiving group notifications.

Android Kotlin

FirebaseMessaging.getInstance().[1]("news")

Drag options to blanks, or click blank then click option'

AgetToken

BunsubscribeFromTopic

CsubscribeToTopic

DsendMessage

Attempts:

3 left

💡 Hint

Common Mistakes

Using getToken instead of subscribeToTopic

Trying to unsubscribe instead of subscribe

Calling sendMessage which is not a client method

The subscribeToTopic() method subscribes the device to a topic so it can receive messages sent to that topic.

3fill in blank

hard

Fix the error in the code to handle incoming messages by overriding the correct method in FirebaseMessagingService.

Android Kotlin

override fun [1](remoteMessage: RemoteMessage) {
    // Handle message here
}

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AonNewToken

BonMessageReceived

ConMessageSent

DonDeletedMessages

Attempts:

3 left

💡 Hint

Common Mistakes

Overriding onNewToken instead of onMessageReceived

Using onMessageSent which is for message sending confirmation

Using onDeletedMessages which handles deleted messages

The onMessageReceived method is called when a message is received. Overriding it lets you handle incoming push notifications.

4fill in blank

hard

Fill both blanks to create a notification channel for Android 8.0+ devices.

Android Kotlin

val channel = NotificationChannel("channel_id", "[1]", [2])
notificationManager.createNotificationChannel(channel)

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AGeneral Notifications

BNotificationManager.IMPORTANCE_HIGH

CIMPORTANCE_LOW

DNews Alerts

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong importance constant like IMPORTANCE_LOW

Putting the channel ID instead of the channel name

Not creating the notification channel at all

The first blank is the user-visible channel name. The second blank is the importance level constant IMPORTANCE_HIGH to show notifications prominently.

5fill in blank

hard

Fill all three blanks to build and show a notification with a title and text.

Android Kotlin

val notification = NotificationCompat.Builder(this, "channel_id")
    .setContentTitle("[1]")
    .setContentText("[2]")
    .setSmallIcon([3])
    .build()
notificationManager.notify(1, notification)

Drag options to blanks, or click blank then click option'

ANew Message

BYou have a new notification

CR.drawable.ic_notification

DR.drawable.ic_launcher

Attempts:

3 left

💡 Hint

Common Mistakes

Using launcher icon instead of notification icon

Including quotes around title and text strings

Omitting the small icon which causes errors

The title is "New Message", the text is "You have a new notification", and the small icon uses the notification icon resource R.drawable.ic_notification.