Receive Messages in an Android App

Firebase notifications behave differently depending on the foreground/background state of the receiving app. If you want foregrounded apps to receive notification messages or data messages, you’ll need to write code to handle the onMessageReceived callback. For an explanation of the difference between notification and data messages, see Message types.

Handling messages

To receive messages, use a service that extends FirebaseMessagingService. Your service should override the onMessageReceived and onDeletedMessages callbacks. It should handle any message within 20 seconds of receipt (10 seconds on Android Marshmallow). The time window may be shorter depending on OS delays incurred ahead of calling onMessageReceived. After that time, various OS behaviors such as Android O's background execution limits may interfere with your ability to complete your work. For more information see our overview on message priority.

onMessageReceived is provided for most message types, with the following exceptions:

• Notification messages delivered when your app is in the background. In this case, the notification is delivered to the device’s system tray. A user tap on a notification opens the app launcher by default.

• Messages with both notification and data payload, both background and foreground. In this case, the notification is delivered to the device’s system tray, and the data payload is delivered in the extras of the intent of your launcher Activity.

In summary:

App state	Notification	Data	Both
Foreground	onMessageReceived	onMessageReceived	onMessageReceived
Background	System tray	onMessageReceived	Notification: system tray Data: in extras of the intent.

For more information about message types, see Notifications and data messages.

Edit the app manifest

To use FirebaseMessagingService, you need to add the following in your app manifest:

<service android:name=".java.MyFirebaseMessagingService">
    <intent-filter>
        <action android:name="com.google.firebase.MESSAGING_EVENT" />
    </intent-filter>
</service>
AndroidManifest.xml

Also, you're recommended to set default values to customize the appearance of notifications. You can specify a custom default icon and a custom default color that are applied whenever equivalent values are not set in the notification payload.

Add these lines inside the application tag to set the custom default icon and custom color:

<!-- Set custom default icon. This is used when no icon is set for incoming notification messages.
     See README(https://goo.gl/l4GJaQ) for more. -->
<meta-data
    android:name="com.google.firebase.messaging.default_notification_icon"
    android:resource="@drawable/ic_stat_ic_notification" />
<!-- Set color used with incoming notification messages. This is used when no color is set for the incoming
     notification message. See README(https://goo.gl/6BKBk7) for more. -->
<meta-data
    android:name="com.google.firebase.messaging.default_notification_color"
    android:resource="@color/colorAccent" />
AndroidManifest.xml

Android displays the custom default icon for

• All notification messages sent from the Notifications composer.
• Any notification message that does not explicitly set the icon in the notification payload.

Android uses the custom default color for

• All notification messages sent from the Notifications composer.
• Any notification message that does not explicitly set the color in the notification payload.

If no custom default icon is set and no icon is set in the notification payload, Android displays the application icon rendered in white.

Override onMessageReceived

By overriding the method FirebaseMessagingService.onMessageReceived, you can perform actions based on the received RemoteMessage object and get the message data:

@Override
public void onMessageReceived(RemoteMessage remoteMessage) {
    // ...

    // TODO(developer): Handle FCM messages here.
    // Not getting messages here? See why this may be: https://goo.gl/39bRNJ
    Log.d(TAG, "From: " + remoteMessage.getFrom());

    // Check if message contains a data payload.
    if (remoteMessage.getData().size() > 0) {
        Log.d(TAG, "Message data payload: " + remoteMessage.getData());

        if (/* Check if data needs to be processed by long running job */ true) {
            // For long-running tasks (10 seconds or more) use Firebase Job Dispatcher.
            scheduleJob();
        } else {
            // Handle message within 10 seconds
            handleNow();
        }

    }

    // Check if message contains a notification payload.
    if (remoteMessage.getNotification() != null) {
        Log.d(TAG, "Message Notification Body: " + remoteMessage.getNotification().getBody());
    }

    // Also if you intend on generating your own notifications as a result of a received FCM
    // message, here is where that should be initiated. See sendNotification method below.
}
MyFirebaseMessagingService.java

Override onDeletedMessages

In some situations, FCM may not deliver a message. This occurs when there are too many messages (>100) pending for your app on a particular device at the time it connects or if the device hasn't connected to FCM in more than one month. In these cases, you may receive a callback to FirebaseMessagingService.onDeletedMessages() When the app instance receives this callback, it should perform a full sync with your app server. If you haven't sent a message to the app on that device within the last 4 weeks, FCM won't call onDeletedMessages().

Handle notification messages in a backgrounded app

When your app is in the background, Android directs notification messages to the system tray. A user tap on the notification opens the app launcher by default.

This includes messages that contain both notification and data payload (and all messages sent from the Notifications console). In these cases, the notification is delivered to the device's system tray, and the data payload is delivered in the extras of the intent of your launcher Activity.

For insight into message delivery to your app, see the FCM reporting dashboard, which records the number of messages sent and opened on iOS and Android devices, along with data for "impressions" (notifications seen by users) for Android apps.

Background Restricted Apps (Android P or newer)

Starting Jan 2019, FCM will not deliver messages to apps which were put into background restriction by the user (such as via: Setting -> Apps and Notification -> [appname] -> Battery). Once your app is removed from background restriction, new messages to the app will be delivered as before. In order to prevent lost messages and other background restriction impacts, make sure to avoid bad behaviors listed by the Android vitals effort. These behaviors could lead to the Android device recommending to the user that your app be background restricted. Your app can check if it is background restricted using: isBackgroundRestricted().