Send a Notification to a User Segment

With user segments, you can send notifications to specific groups of users. You can target predefined user segments or custom audiences created in Firebase Analytics.

Set up the SDK

This section covers tasks you may have completed if you have already enabled other Firebase features for your app.

Prerequisites

• A device running Android 2.3 (Gingerbread) or newer, and Google Play services 9.6.1 or newer
• The Google Repository from the Android SDK Manager
• Android Studio 1.5 or higher

If you don't have an Android Studio project already, you can download one of our quickstart samples if you just want to try a Firebase feature. If you're using a quickstart, remember to get the application ID from the build.gradle file in your project's module folder (typically app/), as you'll need this package name for the next step.

Add Firebase to your app

To add Firebase to your app you'll need a Firebase project and a Firebase configuration file for your app.

1. Create a Firebase project in the Firebase console, if you don't already have one. If you already have an existing Google project associated with your mobile app, click Import Google Project. Otherwise, click Create New Project.
2. Click Add Firebase to your Android app and follow the setup steps. If you're importing an existing Google project, this may happen automatically and you can just download the config file.
3. When prompted, enter your app's package name. It's important to enter the package name your app is using; this can only be set when you add an app to your Firebase project.
4. At the end, you'll download a google-services.json file. You can download this file again at any time.
5. If you haven't done so already, copy this into your project's module folder, typically app/.

Add the SDK

If you would like to integrate the Firebase libraries into one of your own projects, you need to perform a few basic tasks to prepare your Android Studio project. You may have already done this as part of adding Firebase to your app.

First, add rules to your root-level build.gradle file, to include the google-services plugin:

buildscript {
    // ...
    dependencies {
        // ...
        classpath 'com.google.gms:google-services:3.0.0'
    }
}

Then, in your module Gradle file (usually the app/build.gradle), add the apply plugin line at the bottom of the file to enable the Gradle plugin:

apply plugin: 'com.android.application'

android {
  // ...
}

dependencies {
  // ...
  compile 'com.google.firebase:firebase-core:9.6.1'
  compile 'com.google.firebase:firebase-messaging:9.6.1'
  // Getting a "Could not find" error? Make sure you have
  // the latest Google Repository in the Android SDK manager
}

// ADD THIS AT THE BOTTOM
apply plugin: 'com.google.gms.google-services'

You should also add the dependencies for the Firebase SDKs you want to use. We recommend starting with com.google.firebase:firebase-core, which provides Firebase Analytics functionality. See the list of available libraries.

Send a message from the Notifications console

1. Install and run the app on the target devices.

2. Open the Notifications tab of the Firebase console and select New Message.

3. Enter message text.

4. Select the message target. The dialog displays further options to refine the target based on whether you choose App/App Version, Device Language, or Users in Audience.

After you click Send Message, targeted client devices that have the app in the background receive the notification in the system notifications tray. When a user taps on the notification, the app launcher opens your app.

Console fields and the message payload

When you send a notification message from the Notifications console, Google uses the fields entered in the composer in two ways:

1. Fields like User segment and Expires determine the message target and delivery options.
2. Fields like Message text and Custom data are sent to the client in a payload comprised of key/value pairs.

Some of these latter keys are also available through the FCM server API. For example, key/value pairs entered in Custom data are handled as a data payload for the notification. Other fields map directly to keys in the FCM notification payload.

Note that some Notifications console fields are not available through the FCM server API. For example, you can target user segments based on app, app version, or language in ways that are not available using the to field in the server API.

The keys that the Notifications console sends to clients are:

Key	Console field label	Description
notification.title	Message title	Indicates notification title.
notification.body	Message text	Indicates notification body text.
data	Custom data	Key/value pairs that you define. These are delivered as a data payload for the app to handle.

Keys that determine message delivery include:

Key	Console field label	Description
priority	Priority	Sets the priority of the message. For more information, see Setting the priority of a message.
sound	Sound	Indicates a sound to play when the device receives a notification.
time_to_live	Expires	This parameter specifies how long (in seconds) the message should be kept in FCM storage if the device is offline. For more information, see Setting the lifespan of a message.

Receive and handle notifications

If you want to receive notifications when your app is in the foreground, you need to add some message handling logic in your client app.

To receive messages, use a service that extends FirebaseMessagingService. Your service should override the onMessageReceived callback, which is provided for most message types, with the following exceptions:

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

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());
    }

    // 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

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.