Firebase (FCM) how to get token

Question

FASTEST AND GOOD FOR PROTOTYPE

The quick solution is to store it in sharedPrefs and add this logic to onCreate method in your MainActivity or class which is extending Application.

FirebaseInstanceId.getInstance().getInstanceId().addOnSuccessListener(this, instanceIdResult -> {
    String newToken = instanceIdResult.getToken();
    Log.e("newToken", newToken);
    getActivity().getPreferences(Context.MODE_PRIVATE).edit().putString("fb", newToken).apply();
});

Log.d("newToken", getActivity().getPreferences(Context.MODE_PRIVATE).getString("fb", "empty :("));

CLEANER WAY

A better option is to create a service and keep inside a similar logic. Firstly create new Service

public class MyFirebaseMessagingService extends FirebaseMessagingService {

    @Override
    public void onNewToken(String s) {
        super.onNewToken(s);
        Log.e("newToken", s);
        getSharedPreferences("_", MODE_PRIVATE).edit().putString("fb", s).apply();
    }

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);
    }

    public static String getToken(Context context) {
        return context.getSharedPreferences("_", MODE_PRIVATE).getString("fb", "empty");
    }
}

And then add it to AndroidManifest file

<service
        android:name=".MyFirebaseMessagingService"
        android:stopWithTask="false">
        <intent-filter>
            <action android:name="com.google.firebase.MESSAGING_EVENT" />
        </intent-filter>
</service>

Finally, you are able to use a static method from your Service MyFirebaseMessagingService.getToken(Context);

THE FASTEST BUT DEPRECATED

Log.d("Firebase", "token "+ FirebaseInstanceId.getInstance().getToken());

It's still working when you are using older firebase library than version 17.x.x

Complete Solution:

The team behind Firebase Android SDK change API a little bit. I've implemented "Token to Server" logic like this:

In my instance of FirebaseMessagingService:

public class FirebaseCloudMessagingService extends FirebaseMessagingService {

    ...

    @Override
    public void onNewToken(String token) {
        // sending token to server here
    }

    ...

}

Keep in mind that token is per device, and it can be updated by Firebase regardless of your login logic. So, if you have Login and Logout functionality, you have to consider extra cases:

1. When a new user logs in, you need to bind token to the new user (send it to the server). Because token might be updated during the session of old user and server doesn't know token of the new user.
2. When the user logs out, you need to unbind token. Because user should not receive notifications/messages anymore.

Using new API, you can get token like this:

FirebaseInstanceId.getInstance().getInstanceId().addOnSuccessListener(new OnSuccessListener<InstanceIdResult>() {
        @Override
        public void onSuccess(InstanceIdResult instanceIdResult) {
            String token = instanceIdResult.getToken();
            // send it to server
        }
    });

---

Good luck!

FirebaseInstanceId class and it's method getInstanceId are also deprecated. So you have to use FirebaseMessaging class and it's getToken method instead.

FirebaseMessaging.getInstance().getToken().addOnSuccessListener(token -> {
        if (!TextUtils.isEmpty(token)) {
            Log.d(TAG, "retrieve token successful : " + token);
        } else{
            Log.w(TAG, "token should not be null...");
        }
    }).addOnFailureListener(e -> {
        //handle e
    }).addOnCanceledListener(() -> {
        //handle cancel
    }).addOnCompleteListener(task -> Log.v(TAG, "This is the token : " + task.getResult()));

---

The method getToken() is deprecated. You can use getInstanceId() instead.

If you want to handle results when requesting instanceId(token), check this code.

FirebaseInstanceId.getInstance().getInstanceId().addOnSuccessListener(instanceIdResult -> {
        if (instanceIdResult != null) {
            String token = instanceIdResult.getToken();
            if (!TextUtils.isEmpty(token)) {
                Log.d(TAG, "retrieve token successful : " + token);
            }
        } else{
            Log.w(TAG, "instanceIdResult should not be null..");
        }
    }).addOnFailureListener(e -> {
        //do something with e
    }).addOnCanceledListener(() -> {
        //request has canceled
    }).addOnCompleteListener(task -> Log.v(TAG, "task result : " + task.getResult().getToken()));

Important information.

if google play service hung or not running, then fcm return token = null

If play service working properly then FirebaseInstanceId.getInstance().getToken() method returns token

Log.d("FCMToken", "token "+ FirebaseInstanceId.getInstance().getToken());